使用ViewPage实现类launcher屏幕滑动

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http://blog.csdn.net/aomandeshangxiao/article/details/7395526

在去年11月份的时候,自己写过一篇launcher左右滑动的源码分析的文章,launcher修改--左右滑动屏幕切换源码追踪,今年1月份的时候,看到一份有意思的代码,又简单的解析了下代码,写成页面滑动切换(类Launcher滑动屏幕实现),今天又看到一篇使用ViewPage来实现页面滑动,感觉不错,有需要这方面资料的大家可以看下:使用ViewPager实现高仿launcher拖动效果。只不过只提供了代码,没有多少分析,关于ViewPage的资料,大家可以百度下,

下面几个资料,个人都感觉不错:

ViewPager example -实现左右两个屏幕的切换Android的 ViewPager 学习笔记,

viewpager循环拖动,

(android控件)ViewPager介绍和使用说明

,感兴趣的童鞋都可以看下,另外,有两篇word的文档,大家也可以下下来看下:

http://download.csdn.net/detail/aomandeshangxiao/4173947

祝大家快乐!他山之石可以攻玉,好好学习天天向上大笑

网友下面留言给出一个官方更好的demo,大家可以去好好学习下:http://developer.android.com/reference/android/support/v4/view/ViewPager.html


页面滑动切换(类Launcher滑动屏幕实现)

http://blog.csdn.net/aomandeshangxiao/article/details/7196921

下面的这个例子也是从网上找来的,不是自己写的,一直想学习下,但是一直没有写,以前也研究研究的是launcher的页面跳转,launcher修改--左右滑动屏幕切换源码追踪说实话,那个代码有点复杂,所以理解的也不是很透彻。看到这个例子,比较简单些,再这里学习下:

首先,看下效果图吧:虽然很花哨,都是背景图片。


看下他的布局文件:

[html] view plaincopy
  1. <?xmlversion="1.0"encoding="utf-8"?>
  2. <RelativeLayout
  3. android:layout_width="fill_parent"
  4. android:layout_height="fill_parent"
  5. xmlns:android="http://schemas.android.com/apk/res/android">
  6. <com.genius.scroll.MyScrollLayout
  7. xmlns:android="http://schemas.android.com/apk/res/android"
  8. android:id="@+id/ScrollLayout"
  9. android:layout_width="fill_parent"
  10. android:layout_height="fill_parent">
  11. <FrameLayout
  12. android:background="@drawable/guide01"
  13. android:layout_width="fill_parent"
  14. android:layout_height="fill_parent">
  15. </FrameLayout>
  16. <FrameLayout
  17. android:background="@drawable/guide02"
  18. android:layout_width="fill_parent"
  19. android:layout_height="fill_parent">
  20. </FrameLayout>
  21. <FrameLayout
  22. android:background="@drawable/guide03"
  23. android:layout_width="fill_parent"
  24. android:layout_height="fill_parent">
  25. </FrameLayout>
  26. <FrameLayout
  27. android:background="@drawable/guide04"
  28. android:layout_width="fill_parent"
  29. android:layout_height="fill_parent">
  30. </FrameLayout>
  31. <FrameLayout
  32. android:background="@drawable/guide05"
  33. android:layout_width="fill_parent"
  34. android:layout_height="fill_parent">
  35. </FrameLayout>
  36. </com.genius.scroll.MyScrollLayout>
  37. <LinearLayout
  38. android:orientation="horizontal"
  39. android:id="@+id/llayout"
  40. android:layout_width="wrap_content"
  41. android:layout_height="wrap_content"
  42. android:layout_marginBottom="24.0dip"
  43. android:layout_alignParentBottom="true"
  44. android:layout_centerHorizontal="true">
  45. <ImageViewandroid:clickable="true"
  46. android:padding="15.0dip"
  47. android:layout_gravity="center_vertical"
  48. android:layout_width="wrap_content"
  49. android:layout_height="wrap_content"
  50. android:src="@drawable/guide_round"/>
  51. <ImageViewandroid:clickable="true"
  52. android:padding="15.0dip"
  53. android:layout_gravity="center_vertical"
  54. android:layout_width="wrap_content"
  55. android:layout_height="wrap_content"
  56. android:src="@drawable/guide_round"/>
  57. <ImageViewandroid:clickable="true"
  58. android:padding="15.0dip"
  59. android:layout_gravity="center_vertical"
  60. android:layout_width="wrap_content"
  61. android:layout_height="wrap_content"
  62. android:src="@drawable/guide_round"/>
  63. <ImageViewandroid:clickable="true"
  64. android:padding="15.0dip"
  65. android:layout_gravity="center_vertical"
  66. android:layout_width="wrap_content"
  67. android:layout_height="wrap_content"
  68. android:src="@drawable/guide_round"/>
  69. <ImageViewandroid:clickable="true"
  70. android:padding="15.0dip"
  71. android:layout_gravity="center_vertical"
  72. android:layout_width="wrap_content"
  73. android:layout_height="wrap_content"
  74. android:src="@drawable/guide_round"/>
  75. </LinearLayout>
  76. </RelativeLayout>

底部的LinearLayout是放了5个按钮,上面使用到了一个自定义的控件:MyScrollLayout下面再看下这个自定义控件:里面使用frameLayout放了5张图片。

[java] view plaincopy
  1. publicclass MyScrollLayout extends ViewGroup{
  2. privatestaticfinal String TAG = "ScrollLayout";
  3. private VelocityTracker mVelocityTracker; // 用于判断甩动手势
  4. privatestaticfinalint SNAP_VELOCITY = 600;
  5. private Scroller mScroller; // 滑动控制器
  6. privateint mCurScreen;
  7. privateint mDefaultScreen = 0;
  8. privatefloat mLastMotionX;
  9. private OnViewChangeListener mOnViewChangeListener;
  10. public MyScrollLayout(Context context) {
  11. super(context);
  12. init(context);
  13. }
  14. public MyScrollLayout(Context context, AttributeSet attrs) {
  15. super(context, attrs);
  16. init(context);
  17. }
  18. public MyScrollLayout(Context context, AttributeSet attrs, int defStyle) {
  19. super(context, attrs, defStyle);
  20. init(context);
  21. }
  22. privatevoid init(Context context)
  23. {
  24. mCurScreen = mDefaultScreen;
  25. mScroller =new Scroller(context);
  26. }
  27. @Override
  28. protectedvoid onLayout(boolean changed, int l, int t, int r, int b) {
  29. // TODO Auto-generated method stub
  30. if (changed) {
  31. int childLeft = 0;
  32. finalint childCount = getChildCount();
  33. for (int i=0; i<childCount; i++) {
  34. final View childView = getChildAt(i);
  35. if (childView.getVisibility() != View.GONE) {
  36. finalint childWidth = childView.getMeasuredWidth();
  37. childView.layout(childLeft,0,
  38. childLeft+childWidth, childView.getMeasuredHeight());
  39. childLeft += childWidth;
  40. }
  41. }
  42. }
  43. }
  44. @Override
  45. protectedvoid onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
  46. // TODO Auto-generated method stub
  47. super.onMeasure(widthMeasureSpec, heightMeasureSpec);
  48. finalint width = MeasureSpec.getSize(widthMeasureSpec);
  49. finalint widthMode = MeasureSpec.getMode(widthMeasureSpec);
  50. finalint count = getChildCount();
  51. for (int i = 0; i < count; i++) {
  52. getChildAt(i).measure(widthMeasureSpec, heightMeasureSpec);
  53. }
  54. scrollTo(mCurScreen * width,0);
  55. }
  56. publicvoid snapToDestination() {
  57. finalint screenWidth = getWidth();
  58. finalint destScreen = (getScrollX()+ screenWidth/2)/screenWidth;
  59. snapToScreen(destScreen);
  60. }
  61. publicvoid snapToScreen(int whichScreen) {
  62. // get the valid layout page
  63. whichScreen = Math.max(0, Math.min(whichScreen, getChildCount()-1));
  64. if (getScrollX() != (whichScreen*getWidth())) {
  65. finalint delta = whichScreen*getWidth()-getScrollX();
  66. mScroller.startScroll(getScrollX(),0,
  67. delta,0, Math.abs(delta)*2);
  68. mCurScreen = whichScreen;
  69. invalidate();// Redraw the layout
  70. if (mOnViewChangeListener != null)
  71. {
  72. mOnViewChangeListener.OnViewChange(mCurScreen);
  73. }
  74. }
  75. }
  76. @Override
  77. publicvoid computeScroll() {
  78. // TODO Auto-generated method stub
  79. if (mScroller.computeScrollOffset()) {
  80. scrollTo(mScroller.getCurrX(), mScroller.getCurrY());
  81. postInvalidate();
  82. }
  83. }
  84. @Override
  85. publicboolean onTouchEvent(MotionEvent event) {
  86. // TODO Auto-generated method stub
  87. finalint action = event.getAction();
  88. finalfloat x = event.getX();
  89. finalfloat y = event.getY();
  90. switch (action) {
  91. case MotionEvent.ACTION_DOWN:
  92. Log.i("","onTouchEvent ACTION_DOWN");
  93. if (mVelocityTracker == null) {
  94. mVelocityTracker = VelocityTracker.obtain();
  95. mVelocityTracker.addMovement(event);
  96. }
  97. if (!mScroller.isFinished()){
  98. mScroller.abortAnimation();
  99. }
  100. mLastMotionX = x;
  101. break;
  102. case MotionEvent.ACTION_MOVE:
  103. int deltaX = (int)(mLastMotionX - x);
  104. if (IsCanMove(deltaX)){
  105. if (mVelocityTracker != null){
  106. mVelocityTracker.addMovement(event);
  107. }
  108. mLastMotionX = x;
  109. scrollBy(deltaX,0);
  110. }
  111. break;
  112. case MotionEvent.ACTION_UP:
  113. int velocityX = 0;
  114. if (mVelocityTracker != null){
  115. mVelocityTracker.addMovement(event);
  116. mVelocityTracker.computeCurrentVelocity(1000);
  117. velocityX = (int) mVelocityTracker.getXVelocity();
  118. }
  119. if (velocityX > SNAP_VELOCITY && mCurScreen > 0) {
  120. Log.e(TAG,"snap left");
  121. snapToScreen(mCurScreen -1);
  122. }elseif (velocityX < -SNAP_VELOCITY
  123. && mCurScreen < getChildCount() -1) {
  124. Log.e(TAG,"snap right");
  125. snapToScreen(mCurScreen +1);
  126. }else {
  127. snapToDestination();
  128. }
  129. if (mVelocityTracker != null) {
  130. mVelocityTracker.recycle();
  131. mVelocityTracker =null;
  132. }
  133. break;
  134. }
  135. returntrue;
  136. }
  137. privateboolean IsCanMove(int deltaX)
  138. {
  139. if (getScrollX() <= 0 && deltaX < 0 ){
  140. returnfalse;
  141. }
  142. if (getScrollX() >= (getChildCount() - 1) * getWidth() && deltaX > 0){
  143. returnfalse;
  144. }
  145. returntrue;
  146. }
  147. publicvoid SetOnViewChangeListener(OnViewChangeListener listener)
  148. {
  149. mOnViewChangeListener = listener;
  150. }
  151. }

首先注意,他继承了ViewGroup类,在这里面主要重写了onMeasure()、onTouchEvent()等方法,在这里使用了一个自定义的接口private OnViewChangeListener mOnViewChangeListener。看下它的定义:

[java] view plaincopy
  1. publicinterface OnViewChangeListener {
  2. publicvoid OnViewChange(int view);
  3. }

这个接口里之定义了一个回调方法:OnViewChange()这个方法的具体实现,是在主Activity中:

[java] view plaincopy
  1. publicclass SwitchViewDemoActivity extends Activity implements OnViewChangeListener, OnClickListener{
  2. /** Called when the activity is first created. */
  3. private MyScrollLayout mScrollLayout;
  4. private ImageView[] mImageViews;
  5. privateint mViewCount;
  6. privateint mCurSel;
  7. @Override
  8. publicvoid onCreate(Bundle savedInstanceState) {
  9. super.onCreate(savedInstanceState);
  10. setContentView(R.layout.main);
  11. init();
  12. }
  13. privatevoid init()
  14. {
  15. mScrollLayout = (MyScrollLayout) findViewById(R.id.ScrollLayout);
  16. LinearLayout linearLayout = (LinearLayout) findViewById(R.id.llayout);
  17. mViewCount = mScrollLayout.getChildCount();
  18. mImageViews =new ImageView[mViewCount];
  19. for(int i = 0; i < mViewCount; i++) {
  20. mImageViews[i] = (ImageView) linearLayout.getChildAt(i);
  21. mImageViews[i].setEnabled(true);
  22. mImageViews[i].setOnClickListener(this);
  23. mImageViews[i].setTag(i);
  24. }
  25. mCurSel =0;
  26. mImageViews[mCurSel].setEnabled(false);
  27. mScrollLayout.SetOnViewChangeListener(this);
  28. }
  29. privatevoid setCurPoint(int index)
  30. {
  31. if (index < 0 || index > mViewCount - 1 || mCurSel == index) {
  32. return ;
  33. }
  34. mImageViews[mCurSel].setEnabled(true);
  35. mImageViews[index].setEnabled(false);
  36. mCurSel = index;
  37. }
  38. @Override
  39. publicvoid OnViewChange(int view) {
  40. // TODO Auto-generated method stub
  41. setCurPoint(view);
  42. }
  43. @Override
  44. publicvoid onClick(View v) {
  45. // TODO Auto-generated method stub
  46. int pos = (Integer)(v.getTag());
  47. setCurPoint(pos);
  48. mScrollLayout.snapToScreen(pos);
  49. }
  50. }

这个OnViewChange()方法,主要调用了setCurPoint()方法,就是完成界面的跳转。在MyScrollLayout中的snapToScreen()方法中就是典型的回调方法:

[java] view plaincopy
  1. publicvoid snapToScreen(int whichScreen) {
  2. // get the valid layout page
  3. whichScreen = Math.max(0, Math.min(whichScreen, getChildCount()-1));
  4. if (getScrollX() != (whichScreen*getWidth())) {
  5. finalint delta = whichScreen*getWidth()-getScrollX();
  6. mScroller.startScroll(getScrollX(),0,
  7. delta,0, Math.abs(delta)*2);
  8. mCurScreen = whichScreen;
  9. invalidate();// Redraw the layout
  10. if (mOnViewChangeListener != null)
  11. {
  12. mOnViewChangeListener.OnViewChange(mCurScreen);
  13. }
  14. }
  15. }

[java] view plaincopy
  1. mOnViewChangeListener.OnViewChange(mCurScreen);

这句代码就是典型的回调。

在MyScrollLayout的onTouchEvent()的方法里面是对触屏事件做出的响应:

[java] view plaincopy
  1. finalint action = event.getAction();
  2. finalfloat x = event.getX();
  3. finalfloat y = event.getY();
  4. switch (action) {
  5. case MotionEvent.ACTION_DOWN:
  6. Log.i("","onTouchEvent ACTION_DOWN");
  7. if (mVelocityTracker == null) {
  8. mVelocityTracker = VelocityTracker.obtain();
  9. mVelocityTracker.addMovement(event);
  10. }
  11. if (!mScroller.isFinished()){
  12. mScroller.abortAnimation();
  13. }
  14. mLastMotionX = x;
  15. break;
  16. case MotionEvent.ACTION_MOVE:
  17. int deltaX = (int)(mLastMotionX - x);
  18. if (IsCanMove(deltaX)){
  19. if (mVelocityTracker != null){
  20. mVelocityTracker.addMovement(event);
  21. }
  22. mLastMotionX = x;
  23. scrollBy(deltaX,0);
  24. }
  25. break;
  26. case MotionEvent.ACTION_UP:
  27. int velocityX = 0;
  28. if (mVelocityTracker != null){
  29. mVelocityTracker.addMovement(event);
  30. mVelocityTracker.computeCurrentVelocity(1000);
  31. velocityX = (int) mVelocityTracker.getXVelocity();
  32. }
  33. if (velocityX > SNAP_VELOCITY && mCurScreen > 0) {
  34. Log.e(TAG,"snap left");
  35. snapToScreen(mCurScreen -1);
  36. }elseif (velocityX < -SNAP_VELOCITY
  37. && mCurScreen < getChildCount() -1) {
  38. Log.e(TAG,"snap right");
  39. snapToScreen(mCurScreen +1);
  40. }else {
  41. snapToDestination();
  42. }
  43. if (mVelocityTracker != null) {
  44. mVelocityTracker.recycle();
  45. mVelocityTracker =null;
  46. }
  47. break;
  48. }

通过判断移动距离和移动方向做出不同的响应。


其他的代码都比较好懂了,有什么问题欢迎大家讨论,下面是代码的下载地址:

http://download.csdn.net/detail/aomandeshangxiao/4017928

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