Android实现左滑退出Activity的完美封装

public class SildingFinishLayout extends RelativeLayout implements View.OnTouchListener {
  /**
   * SildingFinishLayout布局的父布局
   */
  private ViewGroup mParentView;
  /**
   * 处理滑动逻辑的View
   */
  private View touchView;
  /**
   * 滑动的最小距离
   */
  private int mTouchSlop;
  /**
   * 按下点的X坐标
   */
  private int downX;
  /**
   * 按下点的Y坐标
   */
  private int downY;
  /**
   * 临时存储X坐标
   */
  private int tempX;
  /**
   * 滑动类
   */
  private Scroller mScroller;
  /**
   * SildingFinishLayout的宽度
   */
  private int viewWidth;
  /**
   * 记录是否正在滑动
   */
  private boolean isSilding;


  private OnSildingFinishListener onSildingFinishListener;
  private boolean isFinish;


  public SildingFinishLayout(Context context, AttributeSet attrs) {
    this(context, attrs, 0);
  }


  public SildingFinishLayout(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);


    mTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();
    mScroller = new Scroller(context);
  }


  @Override
  protected void onLayout(boolean changed, int l, int t, int r, int b) {
    super.onLayout(changed, l, t, r, b);
    if (changed) {
// 获取SildingFinishLayout所在布局的父布局
      mParentView = (ViewGroup) this.getParent();
      viewWidth = this.getWidth();
    }
  }


  /**
   * 设置OnSildingFinishListener, 在onSildingFinish()方法中finish Activity
   *
   * @param onSildingFinishListener
   */
  public void setOnSildingFinishListener(
      OnSildingFinishListener onSildingFinishListener) {
    this.OnSildingFinishListener= onSildingFinishListener;
  }


  /**
   * 设置Touch的View
   *
   * @param touchView
   */
  public void setTouchView(View touchView) {
    this.touchView = touchView;
    touchView.setOnTouchListener(this);
  }


  public View getTouchView() {
    return touchView;
  }


  /**
   * 滚动出界面
   */
  private void scrollRight() {
    final int delta = (viewWidth + mParentView.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(mParentView.getScrollX(), 0, -delta + 1, 0,
        Math.abs(delta));
    postInvalidate();
  }


  /**
   * 滚动到起始位置
   */
  private void scrollOrigin() {
    int delta = mParentView.getScrollX();
    mScroller.startScroll(mParentView.getScrollX(), 0, -delta, 0,
        Math.abs(delta));
    postInvalidate();
  }


  /**
   * touch的View是否是AbsListView， 例如ListView, GridView等其子类
   *
   * @return
   */
  private boolean isTouchOnAbsListView() {
    return touchView instanceof AbsListView &＃63; true : false;
  }


  /**
   * touch的view是否是ScrollView或者其子类
   *
   * @return
   */
  private boolean isTouchOnScrollView() {
    return touchView instanceof ScrollView &＃63; true : false;
  }


  @Override
  public boolean onTouch(View v, MotionEvent event) {
    switch (event.getAction()) {
      case MotionEvent.ACTION_DOWN:
        downX = tempX = (int) event.getRawX();
        downY = (int) event.getRawY();
        break;
      case MotionEvent.ACTION_MOVE:
        int moveX = (int) event.getRawX();
        int deltaX = tempX - moveX;
        tempX = moveX;
        if (Math.abs(moveX - downX) > mTouchSlop
            && Math.abs((int) event.getRawY() - downY) = 0 && isSilding) {
          mParentView.scrollBy(deltaX, 0);


// 屏蔽在滑动过程中ListView ScrollView等自己的滑动事件
          if (isTouchOnScrollView() || isTouchOnAbsListView()) {
            return true;
          }
        }
        break;
      case MotionEvent.ACTION_UP:
        isSilding = false;
        if (mParentView.getScrollX() <= -viewWidth / 2) {
          isFinish = true;
          scrollRight();
        } else {
          scrollOrigin();
          isFinish = false;
        }
        break;
    }


// 假如touch的view是AbsListView或者ScrollView 我们处理完上面自己的逻辑之后
// 再交给AbsListView, ScrollView自己处理其自己的逻辑
    if (isTouchOnScrollView() || isTouchOnAbsListView()) {
      return v.onTouchEvent(event);
    }


// 其他的情况直接返回true
    return true;
  }


  @Override
  public void computeScroll() {
// 调用startScroll的时候scroller.computeScrollOffset()返回true，
    if (mScroller.computeScrollOffset()) {
      mParentView.scrollTo(mScroller.getCurrX(), mScroller.getCurrY());
      postInvalidate();


      if (mScroller.isFinished()) {


        if (onSildingFinishListener != null && isFinish) {
          onSildingFinishListener.onSildingFinish();
        }
      }
    }
  }

  public interface OnSildingFinishListener {
    public void onSildingFinish();
  }
}

 @Override
  public void onCreate(@Nullable Bundle savedInstanceState, @Nullable PersistableBundle persistentState) {
    super.onCreate(savedInstanceState, persistentState);
    SildingFinishLayout mSildingFinishLayout = (SildingFinishLayout) findViewById(R.id.timed_task_SildingFinishLayout);
mSildingFinishLayout
    mSildingFinishLayout .setOnSildingFinishListener(new SildingFinishLayout.OnSildingFinishListener() {
      @Override
      public void onSildingFinish() {
        finish();
      }
    });
    mSildingFinishLayout .setTouchView(mSildingFinishLayout);//绑定底层的布局就可以了 :不起作用的话换个你activity 布局里面view就可以啦 
  }

android:theme="@style/AppTheme" 

@null ：Dialog的windowFrame框为无
true：是否浮现在activity之上
false:是否半透明
true:是否显示title
@drawable/dia_bg:设置dialog的背景
false: 背景是否透明显示