关于Android TouchDelegate源码解析
来源：互联网 发布：知我者芈月也 编辑：程序博客网 时间：2024/06/07 10:15
android.view.TouchDelegate是用来扩大View的触摸点击区域的。
用法很简单，套路是：
比如
mButton = new CheckBox(getContext());
Rect bounds = new Rect(0, 0, viewBound.getMeasuredWidth(), viewBound.getMeasuredHeight());
TouchDelegate delegate = new TouchDelegate(bounds, mButton);
viewBound.setTouchDelegate(delegate);
这样就可以扩大mButton的触摸点击区域了，将它的触摸区域设成viewBound的区域，也就是说点viewBound的任何地方都等同于点mButton。
既然是这样那我也可以设置另外一块和mButton毫无交集区域作为viewBound的点击范围。
<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">TouchDelegateLayout</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">extends</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">FrameLayout</span> {</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-title" style="box-sizing: border-box;">TouchDelegateLayout</span>(Context context) { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span>(context); init(); } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-title" style="box-sizing: border-box;">TouchDelegateLayout</span>(Context context, AttributeSet attrs) { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span>(context, attrs); init(); } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-title" style="box-sizing: border-box;">TouchDelegateLayout</span>(Context context, AttributeSet attrs, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> defStyle) { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span>(context, attrs, defStyle); init(); } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> CheckBox mButton; <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">init</span>() { mButton = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> CheckBox(getContext()); mButton.setText(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Click Anywhere On Screen"</span>); addView(mButton, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> FrameLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT, Gravity.CENTER)); } <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">/* * TouchDelegate is applied to this view (parent) to delegate all touches * within the specified rectangle to the CheckBox (child). Here, the rectangle * is the entire size of this parent view. * * This must be done after the view has measured itself so we know how big to make the rect, * thus we've chosen to add the delegate in onMeasure() */</span> <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">protected</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onMeasure</span>(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> widthMeasureSpec, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> heightMeasureSpec) { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span>.onMeasure(widthMeasureSpec, heightMeasureSpec); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//Apply the whole area of this view as the delegate area</span> Rect bounds = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Rect(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>, <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>, getMeasuredWidth()/<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">3</span>, getMeasuredHeight()/<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">3</span>); TouchDelegate delegate = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> TouchDelegate(bounds, mButton); setTouchDelegate(delegate); }}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li><li style="box-sizing: border-box; padding: 0px 5px;">40</li><li style="box-sizing: border-box; padding: 0px 5px;">41</li><li style="box-sizing: border-box; padding: 0px 5px;">42</li></ul>如上，点击FrameLayout的左上角是可以让mButton选中的。为什么可以实现，TouchDelegate为我们做了什么？
<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">TouchDelegate</span> {</span> <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/** * View that should receive forwarded touch events */</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> View mDelegateView; <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/** * Bounds in local coordinates of the containing view that should be mapped to the delegate * view. This rect is used for initial hit testing. */</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> Rect mBounds; <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/** * mBounds inflated to include some slop. This rect is to track whether the motion events * should be considered to be be within the delegate view. */</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> Rect mSlopBounds; <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/** * True if the delegate had been targeted on a down event (intersected mBounds). */</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> mDelegateTargeted; <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/** * The touchable region of the View extends above its actual extent. */</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> ABOVE = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>; <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/** * The touchable region of the View extends below its actual extent. */</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> BELOW = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>; <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/** * The touchable region of the View extends to the left of its * actual extent. */</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> TO_LEFT = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">4</span>; <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/** * The touchable region of the View extends to the right of its * actual extent. */</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> TO_RIGHT = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">8</span>; <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> mSlop; <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/** * Constructor * *<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @param</span> bounds Bounds in local coordinates of the containing view that should be mapped to * the delegate view *<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @param</span> delegateView The view that should receive motion events */</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-title" style="box-sizing: border-box;">TouchDelegate</span>(Rect bounds, View delegateView) { mBounds = bounds; mSlop = ViewConfiguration.get(delegateView.getContext()).getScaledTouchSlop(); mSlopBounds = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Rect(bounds); mSlopBounds.inset(-mSlop, -mSlop); mDelegateView = delegateView; } <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/** * Will forward touch events to the delegate view if the event is within the bounds * specified in the constructor. * *<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @param</span> event The touch event to forward *<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @return</span> True if the event was forwarded to the delegate, false otherwise. */</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> <span class="hljs-title" style="box-sizing: border-box;">onTouchEvent</span>(MotionEvent event) { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> x = (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span>)event.getX(); <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> y = (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span>)event.getY(); <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> sendToDelegate = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>; <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> hit = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>; <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> handled = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>; <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">switch</span> (event.getAction()) { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">case</span> MotionEvent.ACTION_DOWN: Rect bounds = mBounds; <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (bounds.contains(x, y)) { mDelegateTargeted = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>; sendToDelegate = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>; } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">break</span>; <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">case</span> MotionEvent.ACTION_UP: <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">case</span> MotionEvent.ACTION_MOVE: sendToDelegate = mDelegateTargeted; <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (sendToDelegate) { Rect slopBounds = mSlopBounds; <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (!slopBounds.contains(x, y)) { hit = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>; } } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">break</span>; <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">case</span> MotionEvent.ACTION_CANCEL: sendToDelegate = mDelegateTargeted; mDelegateTargeted = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>; <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">break</span>; } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (sendToDelegate) { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> View delegateView = mDelegateView; <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (hit) { <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// Offset event coordinates to be inside the target view</span> event.setLocation(delegateView.getWidth() / <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>, delegateView.getHeight() / <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>); } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> { <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// Offset event coordinates to be outside the target view (in case it does</span> <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// something like tracking pressed state)</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> slop = mSlop; event.setLocation(-(slop * <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>), -(slop * <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>)); } handled = delegateView.dispatchTouchEvent(event); } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> handled; }}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; 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padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li><li style="box-sizing: border-box; padding: 0px 5px;">40</li><li style="box-sizing: border-box; padding: 0px 5px;">41</li><li style="box-sizing: border-box; padding: 0px 5px;">42</li><li style="box-sizing: border-box; padding: 0px 5px;">43</li><li style="box-sizing: border-box; padding: 0px 5px;">44</li><li style="box-sizing: border-box; padding: 0px 5px;">45</li><li style="box-sizing: border-box; padding: 0px 5px;">46</li><li style="box-sizing: border-box; padding: 0px 5px;">47</li><li style="box-sizing: border-box; padding: 0px 5px;">48</li><li style="box-sizing: border-box; padding: 0px 5px;">49</li><li style="box-sizing: border-box; padding: 0px 5px;">50</li><li style="box-sizing: border-box; padding: 0px 5px;">51</li><li style="box-sizing: border-box; padding: 0px 5px;">52</li><li style="box-sizing: border-box; padding: 0px 5px;">53</li><li style="box-sizing: border-box; padding: 0px 5px;">54</li><li style="box-sizing: border-box; padding: 0px 5px;">55</li><li style="box-sizing: border-box; padding: 0px 5px;">56</li><li style="box-sizing: border-box; padding: 0px 5px;">57</li><li style="box-sizing: border-box; padding: 0px 5px;">58</li><li style="box-sizing: border-box; padding: 0px 5px;">59</li><li style="box-sizing: border-box; padding: 0px 5px;">60</li><li style="box-sizing: border-box; padding: 0px 5px;">61</li><li style="box-sizing: border-box; padding: 0px 5px;">62</li><li style="box-sizing: border-box; padding: 0px 5px;">63</li><li style="box-sizing: border-box; padding: 0px 5px;">64</li><li style="box-sizing: border-box; padding: 0px 5px;">65</li><li style="box-sizing: border-box; padding: 0px 5px;">66</li><li style="box-sizing: border-box; padding: 0px 5px;">67</li><li style="box-sizing: border-box; padding: 0px 5px;">68</li><li style="box-sizing: border-box; padding: 0px 5px;">69</li><li style="box-sizing: border-box; padding: 0px 5px;">70</li><li style="box-sizing: border-box; padding: 0px 5px;">71</li><li style="box-sizing: border-box; padding: 0px 5px;">72</li><li style="box-sizing: border-box; padding: 0px 5px;">73</li><li style="box-sizing: border-box; padding: 0px 5px;">74</li><li style="box-sizing: border-box; padding: 0px 5px;">75</li><li style="box-sizing: border-box; padding: 0px 5px;">76</li><li style="box-sizing: border-box; padding: 0px 5px;">77</li><li style="box-sizing: border-box; padding: 0px 5px;">78</li><li style="box-sizing: border-box; padding: 0px 5px;">79</li><li style="box-sizing: border-box; padding: 0px 5px;">80</li><li style="box-sizing: border-box; padding: 0px 5px;">81</li><li style="box-sizing: border-box; padding: 0px 5px;">82</li><li style="box-sizing: border-box; padding: 0px 5px;">83</li><li style="box-sizing: border-box; padding: 0px 5px;">84</li><li style="box-sizing: border-box; padding: 0px 5px;">85</li><li style="box-sizing: border-box; padding: 0px 5px;">86</li><li style="box-sizing: border-box; padding: 0px 5px;">87</li><li style="box-sizing: border-box; padding: 0px 5px;">88</li><li style="box-sizing: border-box; padding: 0px 5px;">89</li><li style="box-sizing: border-box; padding: 0px 5px;">90</li><li style="box-sizing: border-box; padding: 0px 5px;">91</li><li style="box-sizing: border-box; padding: 0px 5px;">92</li><li style="box-sizing: border-box; padding: 0px 5px;">93</li><li style="box-sizing: border-box; padding: 0px 5px;">94</li><li style="box-sizing: border-box; padding: 0px 5px;">95</li><li style="box-sizing: border-box; padding: 0px 5px;">96</li><li style="box-sizing: border-box; padding: 0px 5px;">97</li><li style="box-sizing: border-box; padding: 0px 5px;">98</li><li style="box-sizing: border-box; padding: 0px 5px;">99</li><li style="box-sizing: border-box; padding: 0px 5px;">100</li><li style="box-sizing: border-box; padding: 0px 5px;">101</li><li style="box-sizing: border-box; padding: 0px 5px;">102</li><li style="box-sizing: border-box; padding: 0px 5px;">103</li><li style="box-sizing: border-box; padding: 0px 5px;">104</li><li style="box-sizing: border-box; padding: 0px 5px;">105</li><li style="box-sizing: border-box; padding: 0px 5px;">106</li><li style="box-sizing: border-box; padding: 0px 5px;">107</li><li style="box-sizing: border-box; padding: 0px 5px;">108</li><li style="box-sizing: border-box; padding: 0px 5px;">109</li><li style="box-sizing: border-box; padding: 0px 5px;">110</li><li style="box-sizing: border-box; padding: 0px 5px;">111</li><li style="box-sizing: border-box; padding: 0px 5px;">112</li><li style="box-sizing: border-box; padding: 0px 5px;">113</li><li style="box-sizing: border-box; padding: 0px 5px;">114</li><li style="box-sizing: border-box; padding: 0px 5px;">115</li><li style="box-sizing: border-box; padding: 0px 5px;">116</li><li style="box-sizing: border-box; padding: 0px 5px;">117</li><li style="box-sizing: border-box; padding: 0px 5px;">118</li><li style="box-sizing: border-box; padding: 0px 5px;">119</li></ul>可以看出TouchDelegate仅仅是一个普通的不能再普通的java类而已。代码不多，就一个构造方法和一个onTouchEvent方法，而且这个onTouchEvent方法不是重写的，仅仅是自己定义的方法取这么个名字。那这个方法在哪调用的呢？
是在View.java里的
<code class="hljs cs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> boolean <span class="hljs-title" style="box-sizing: border-box;">onTouchEvent</span>(MotionEvent <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">event</span>) { final <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">float</span> x = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">event</span>.getX(); final <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">float</span> y = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">event</span>.getY(); final <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> viewFlags = mViewFlags; <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> ((viewFlags & ENABLED_MASK) == DISABLED) { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">event</span>.getAction() == MotionEvent.ACTION_UP && (mPrivateFlags & PFLAG_PRESSED) != <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>) { setPressed(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>); } <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// A disabled view that is clickable still consumes the touch</span> <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// events, it just doesn't respond to them.</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> (((viewFlags & CLICKABLE) == CLICKABLE || (viewFlags & LONG_CLICKABLE) == LONG_CLICKABLE)); } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (mTouchDelegate != <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>) { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (mTouchDelegate.onTouchEvent(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">event</span>)) { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>; } }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li></ul>里面调用的，看到这里大家明白了，原来点击FrameLayout势必会调用到View.java里的onTouchEvent里来，然后又设了代理TouchDelegate，所有势必会调用TouchDelegate里的onTouchEvent方法。
现在我们来看此方法怎么做到的。
这是它的构造方法
<code class="hljs cs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-title" style="box-sizing: border-box;">TouchDelegate</span>(Rect bounds, View delegateView) {<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//把Rect点击区域赋值</span> mBounds = bounds;<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//拿到android定义的touch边界值</span> mSlop = ViewConfiguration.<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">get</span>(delegateView.getContext()).getScaledTouchSlop(); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//初始化touch边界值的Rect区域，初始化时直接用传过来的rect</span> mSlopBounds = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Rect(bounds); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//跟进代码里，则个方法意思是让这个Rect区域变宽点，可以看源码注释</span> mSlopBounds.inset(-mSlop, -mSlop); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//需要代理的view，上面里例子就是FrameLayout里的mButton</span> mDelegateView = delegateView; }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li></ul>OK，现在来看onTouchEvent
<code class="hljs cs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//注意这里变量的命名，很规范，让人一看就明白什么意思</span><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> boolean <span class="hljs-title" style="box-sizing: border-box;">onTouchEvent</span>(MotionEvent <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">event</span>) { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> x = (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span>)<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">event</span>.getX(); <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> y = (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span>)<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">event</span>.getY(); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//是否发生event事件给需要代理的view</span> boolean sendToDelegate = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>; <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//是否点击在需代理的view上，这里不好翻译，大致意思看后面</span> boolean hit = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>; <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//是否已处理</span> boolean handled = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>; <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">switch</span> (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">event</span>.getAction()) { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">case</span> MotionEvent.ACTION_DOWN: Rect bounds = mBounds;<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//down事件包含在rect区域里，要发event事件给需代理的view</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (bounds.contains(x, y)) { mDelegateTargeted = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>; sendToDelegate = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>; } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">break</span>; <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">case</span> MotionEvent.ACTION_UP: <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">case</span> MotionEvent.ACTION_MOVE: sendToDelegate = mDelegateTargeted; <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (sendToDelegate) { Rect slopBounds = mSlopBounds; <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//用ScaleTouchSlop扩大的区域是否包含了event的x y坐标，hit默认为true，默认包含</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (!slopBounds.contains(x, y)) { hit = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>; } } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">break</span>; <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">case</span> MotionEvent.ACTION_CANCEL: sendToDelegate = mDelegateTargeted; mDelegateTargeted = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>; <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">break</span>; } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (sendToDelegate) { final View delegateView = mDelegateView; <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (hit) { <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// Offset event coordinates to be inside the target view</span> <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//这里重设了event的坐标，刚开始不明白setLocation用法，特别是跟到源码里看就更不明白了，发现源码里有个offsetLocation(x - oldX, y - oldY)方法，这个方法实现了ViewGroup中的childView上的touchEvent事件的x y坐标是相对于自身的左上角为00的边界。</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">event</span>.setLocation(delegateView.getWidth() / <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>, delegateView.getHeight() / <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>); } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> { <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// Offset event coordinates to be outside the target view (in case it does</span> <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// something like tracking pressed state)</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> slop = mSlop; <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//上面英文解释也很清楚，是为了追踪preesed状态的，就是当move事件一直移动还没up前移出了设定的rect点击区域的时候需要重写设置event的坐标</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">event</span>.setLocation(-(slop * <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>), -(slop * <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>)); } handled = delegateView.dispatchTouchEvent(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">event</span>); } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> handled; }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li><li style="box-sizing: border-box; padding: 0px 5px;">40</li><li style="box-sizing: border-box; padding: 0px 5px;">41</li><li style="box-sizing: border-box; padding: 0px 5px;">42</li><li style="box-sizing: border-box; padding: 0px 5px;">43</li><li style="box-sizing: border-box; padding: 0px 5px;">44</li><li style="box-sizing: border-box; padding: 0px 5px;">45</li><li style="box-sizing: border-box; padding: 0px 5px;">46</li><li style="box-sizing: border-box; padding: 0px 5px;">47</li><li style="box-sizing: border-box; padding: 0px 5px;">48</li><li style="box-sizing: border-box; padding: 0px 5px;">49</li><li style="box-sizing: border-box; padding: 0px 5px;">50</li><li style="box-sizing: border-box; padding: 0px 5px;">51</li><li style="box-sizing: border-box; padding: 0px 5px;">52</li><li style="box-sizing: border-box; padding: 0px 5px;">53</li><li style="box-sizing: border-box; padding: 0px 5px;">54</li></ul>Ok，这里就分析差不多了，至少我弄明白了。
然后说说MotionEvent里的offsetLocation方法，在ViewGroup中用来将childView的touchEvent的坐标偏移成相对自身左上角为0点的起始坐标的。
引用篇博客http://blog.csdn.net/bigconvience/article/details/26391743
<code class="hljs cs has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> boolean <span class="hljs-title" style="box-sizing: border-box;">dispatchTransformedTouchEvent</span>(MotionEvent <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">event</span>, boolean cancel, View child, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> desiredPointerIdBits) { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (child == <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span> || child.hasIdentityMatrix()) { <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (child == <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>) { handled = super.dispatchTouchEvent(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">event</span>); } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> { final <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">float</span> offsetX = mScrollX - child.mLeft; final <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">float</span> offsetY = mScrollY - child.mTop; <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">/*直接对MotionEvent进行坐标变换，将MotionEvent传递下去*/</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">event</span>.offsetLocation(offsetX, offsetY); handled = child.dispatchTouchEvent(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">event</span>); <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">/*回复MotionEvent*/</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">event</span>.offsetLocation(-offsetX, -offsetY); } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> handled; } </code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li></ul>主要是上面先偏移event.offsetLocation(offsetX, offsetY);
然后再偏移回来event.offsetLocation(-offsetX, -offsetY);
中间让childView自己去分发TouchEvent
handled = child.dispatchTouchEvent(event);
所以到这里整个TouchDelegate类里的所有疑问都理清楚了，完全可以自己实现一个类似的类了，不错！
主要是觉得这个类简单但是可以学习的东西很多，遂连夜记录下来！共勉
版权声明：本文为博主原创文章，未经博主允许不得转载。
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