android activity右滑退出

       主流APP都会要求有这样的一个功能，不想点顶部返回按钮退出界面，而习惯右滑退出界面，那就此功能实现步骤分享如下：

1.  在Activity onCreate生命周期中写如代码：要在setContentVIew之前

   

@Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        layout = (SwipeBackLayout) LayoutInflater.from(this).inflate(                R.layout.base, null);        layout.attachToActivity(this);        setContentView(R.layout.act_detail_info);          }

如下为base.xml文件内容：

</pre><pre name="code" class="html"><packagename.widget.layout.SwipeBackLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"></packagename.widget.layout.SwipeBackLayout>

如下为SwipeBackLayout.java 内容：

public class SwipeBackLayout extends FrameLayout {    private static final String TAG = SwipeBackLayout.class.getSimpleName();    private View mContentView;    private int mTouchSlop;    private int downX;    private int downY;    private int tempX;    private Scroller mScroller;    private int viewWidth;    private boolean isSilding;    private boolean isFinish;    private Drawable mShadowDrawable;    private Activity mActivity;    private List<ViewPager> mViewPagers = new LinkedList<ViewPager>();    public SwipeBackLayout(Context context, AttributeSet attrs) {        this(context, attrs, 0);    }    public SwipeBackLayout(Context context, AttributeSet attrs, int defStyle) {        super(context, attrs, defStyle);        //触发移动事件的最短距离，如果小于这个距离就不触发移动控件        mTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();        mScroller = new Scroller(context);        mShadowDrawable = getResources().getDrawable(R.drawable.shadow_left);    }    public void attachToActivity(Activity activity) {        mActivity = activity;        TypedArray a = activity.getTheme().obtainStyledAttributes(                new int[]{android.R.attr.windowBackground});        int background = a.getResourceId(0, 0);        a.recycle();        ViewGroup decor = (ViewGroup) activity.getWindow().getDecorView();        ViewGroup decorChild = (ViewGroup) decor.getChildAt(0);        decorChild.setBackgroundResource(background);        decor.removeView(decorChild);        addView(decorChild);        setContentView(decorChild);        decor.addView(this);    }    private void setContentView(View decorChild) {        mContentView = (View) decorChild.getParent();    }    /**     * 事件拦截操作     */    @Override    public boolean onInterceptTouchEvent(MotionEvent ev) {        //处理ViewPager冲突问题        ViewPager mViewPager = getTouchViewPager(mViewPagers, ev);        Log.i(TAG, "mViewPager = " + mViewPager);        if (mViewPager != null && mViewPager.getCurrentItem() != 0) {            return super.onInterceptTouchEvent(ev);        }        switch (ev.getAction()) {            case MotionEvent.ACTION_DOWN:                downX = tempX = (int) ev.getRawX();                downY = (int) ev.getRawY();                break;            case MotionEvent.ACTION_MOVE:                int moveX = (int) ev.getRawX();                // 满足此条件屏蔽SildingFinishLayout里面子类的touch事件                if (moveX - downX > mTouchSlop                        && Math.abs((int) ev.getRawY() - downY) < mTouchSlop) {                    return true;                }                break;        }        return super.onInterceptTouchEvent(ev);    }    @Override    public boolean onTouchEvent(MotionEvent event) {        switch (event.getAction()) {            case MotionEvent.ACTION_MOVE:                int moveX = (int) event.getRawX();                int deltaX = tempX - moveX;                tempX = moveX;                if (moveX - downX > mTouchSlop                        && Math.abs((int) event.getRawY() - downY) < mTouchSlop) {                    isSilding = true;                }                if (moveX - downX >= 0 && isSilding) {                    mContentView.scrollBy(deltaX, 0);                }                break;            case MotionEvent.ACTION_UP:                isSilding = false;                if (mContentView.getScrollX() <= -viewWidth / 2) {                    isFinish = true;                    scrollRight();                } else {                    scrollOrigin();                    isFinish = false;                }                break;        }        return true;    }    /**     * 获取SwipeBackLayout里面的ViewPager的集合     *     * @param mViewPagers     * @param parent     */    private void getAlLViewPager(List<ViewPager> mViewPagers, ViewGroup parent) {        int childCount = parent.getChildCount();        for (int i = 0; i < childCount; i++) {            View child = parent.getChildAt(i);            if (child instanceof ViewPager) {                mViewPagers.add((ViewPager) child);            } else if (child instanceof ViewGroup) {                getAlLViewPager(mViewPagers, (ViewGroup) child);            }        }    }    /**     * 返回我们touch的ViewPager     *     * @param mViewPagers     * @param ev     * @return     */    private ViewPager getTouchViewPager(List<ViewPager> mViewPagers, MotionEvent ev) {        if (mViewPagers == null || mViewPagers.size() == 0) {            return null;        }        Rect mRect = new Rect();        for (ViewPager v : mViewPagers) {            v.getHitRect(mRect);            if (mRect.contains((int) ev.getX(), (int) ev.getY())) {                return v;            }        }        return null;    }    @Override    protected void onLayout(boolean changed, int l, int t, int r, int b) {        super.onLayout(changed, l, t, r, b);        if (changed) {            viewWidth = this.getWidth();            getAlLViewPager(mViewPagers, this);            Log.i(TAG, "ViewPager size = " + mViewPagers.size());        }    }    @Override    protected void dispatchDraw(Canvas canvas) {        super.dispatchDraw(canvas);        if (mShadowDrawable != null && mContentView != null) {            int left = mContentView.getLeft()                    - mShadowDrawable.getIntrinsicWidth();            int right = left + mShadowDrawable.getIntrinsicWidth();            int top = mContentView.getTop();            int bottom = mContentView.getBottom();            mShadowDrawable.setBounds(left, top, right, bottom);            mShadowDrawable.draw(canvas);        }    }    /**     * 滚动出界面     */    private void scrollRight() {        final int delta = (viewWidth + mContentView.getScrollX());        // 调用startScroll方法来设置一些滚动的参数，我们在computeScroll()方法中调用scrollTo来滚动item        mScroller.startScroll(mContentView.getScrollX(), 0, -delta + 1, 0,                Math.abs(delta));        postInvalidate();    }    /**     * 滚动到起始位置     */    private void scrollOrigin() {        int delta = mContentView.getScrollX();        mScroller.startScroll(mContentView.getScrollX(), 0, -delta, 0,                Math.abs(delta));        postInvalidate();    }    @Override    public void computeScroll() {        // 调用startScroll的时候scroller.computeScrollOffset()返回true，        if (mScroller.computeScrollOffset()) {            mContentView.scrollTo(mScroller.getCurrX(), mScroller.getCurrY());            postInvalidate();            if (mScroller.isFinished() && isFinish) {                mActivity.finish();            }        }    }}

图片资源：

shadow_left.png

2.  为了体验效果更爽， activity进入的时候应该是从左边进入过渡。

  重写activity    startActivity(Intent intent) 方法：

@Override    public void startActivity(Intent intent) {        super.startActivity(intent);        overridePendingTransition(R.anim.base_slide_right_in, R.anim.base_slide_remain);    }

如下： base_slide_right_in.xml 内容：

<?xml version="1.0" encoding="utf-8"?><set xmlns:android="http://schemas.android.com/apk/res/android" >    <translate        android:duration="300"        android:fromXDelta="100.0%"        android:interpolator="@android:anim/decelerate_interpolator"        android:toXDelta="0.0%" /></set>

如下： base_slide_remain.xml内容：

<?xml version="1.0" encoding="utf-8"?><set xmlns:android="http://schemas.android.com/apk/res/android" >    <translate        android:duration="300"        android:fromXDelta="0"        android:interpolator="@android:anim/decelerate_interpolator"        android:toXDelta="0" /></set>