SwipeLayout一个展示条目底层菜单的侧滑控件

   <p>由于项目上的需要侧滑条目展示收藏按钮,记得之前代码家有写过一个厉害的开源控件 AndroidSwipeLayout 本来准备直接拿来使用,但是看过 issue 发现现在有不少使用者反应有不少的 bug ,而且代码家现在貌似也不进行维护了.故自己实现了一个所要效果的一个控件.因为只是实现我需要的效果,所以大家也能看到,代码里有不少地方我是写死的.希望对大家有些帮助.而且暂时也不需要 AndroidSwipeLayout 大而全的功能,算是变相给自己做的项目精简代码了.</p>    <p>主要源码:</p>    <pre>  <code class="language-java">public class SwipeLayout extends FrameLayout {        public static final int CLOSE = 0;      public static final int OPEN = 1;      private int mState = CLOSE;      private int mWidth;      private int mHeight;      private float mDownX;      private float mDownY;        private SwipeListener mSwipeListener;      private View mTopView;      private View mBottomView;      private ViewDragHelper mViewDragHelper;          public SwipeLayout(Context context) {          this(context, null);      }        public SwipeLayout(Context context, AttributeSet attrs) {          this(context, attrs, 0);      }        public SwipeLayout(Context context, AttributeSet attrs, int defStyleAttr) {          super(context, attrs, defStyleAttr);          mViewDragHelper = ViewDragHelper.create(this, new ViewDragHelper.Callback() {              @Override              public boolean tryCaptureView(View child, int pointerId) {//只对mTopView进行处理                  return child == mTopView;              }                @Override              public int clampViewPositionHorizontal(View child, int left, int dx) {//设置横向滑动的边界(left的值是mTopView左上角点的x坐标值)                  int newLeft;                  if (left <= -mBottomView.getMeasuredWidth()) {                      newLeft = -mBottomView.getMeasuredWidth();                  } else if (left >= 0) {                      newLeft = 0;                  } else {                      newLeft = left;                  }                  return newLeft;              }                @Override              public int clampViewPositionVertical(View child, int top, int dy) {//因为不需要上下的滑动直接设置为0(top的值是mTopView左上角点的y坐标值)                  return 0;              }                @Override              public void onViewReleased(View releasedChild, float xvel, float yvel) {//手指松开时会回调该函数                  int right = mWidth - releasedChild.getRight();//mTopView右边界距离屏幕右边的距离                  int bottomWidth = mBottomView.getMeasuredWidth();                  if (right > bottomWidth * 9 / 10) {                      scrollToLeftEdge();                      return;                  }                  if (right <= bottomWidth / 10 && right > 0) {                      scrollToRightEdge();                      return;                  }                  if (xvel == 0) {//速度为0时单独处理                      if (right >= bottomWidth / 2) {                          scrollToLeftEdge();                      } else if (right < bottomWidth / 2) {                          scrollToRightEdge();                      }                      return;                  }                  if (xvel > 0) {//向右滑动后松手                      scrollToRightEdge();                  } else {//向左滑动后松手                      scrollToLeftEdge();                  }              }          });      }        @Override      public void computeScroll() {          if (mViewDragHelper.continueSettling(true)) {              invalidate();          }      }        @Override      public boolean onInterceptTouchEvent(MotionEvent ev) {          switch (ev.getAction()) {              case MotionEvent.ACTION_DOWN:                  mDownX = ev.getRawX();                  mDownY = ev.getRawY();                  if (mState == CLOSE) {                      return true;                  }                  break;              case MotionEvent.ACTION_MOVE:                  float distanceX = ev.getRawX() - mDownX;                  float distanceY = ev.getRawY() - mDownY;                  float angle;                  if (distanceX == 0) {                      angle = 90;                  } else {                      angle = (float) Math.toDegrees(Math.atan(Math.abs(distanceY / distanceX)));                  }                  if (angle < 45) {                      return true;//拦截事件交给自己处理滑动                  }                  break;          }          return mViewDragHelper.shouldInterceptTouchEvent(ev);      }        @Override      public boolean onTouchEvent(MotionEvent ev) {          ViewParent viewParent = getParent();          switch (ev.getAction()) {              case MotionEvent.ACTION_DOWN:                  mDownX = ev.getRawX();                  mDownY = ev.getRawY();                  break;              case MotionEvent.ACTION_MOVE:                  float distanceX = ev.getRawX() - mDownX;                  float distanceY = ev.getRawY() - mDownY;                  float angle;                  if (distanceX == 0) {                      angle = 90;                  } else {                      angle = (float) Math.toDegrees(Math.atan(Math.abs(distanceY / distanceX)));                  }                  if (angle < 45 && viewParent != null) {                      viewParent.requestDisallowInterceptTouchEvent(true);//让父控件不要处理事件,交给子控件                  }                  break;              case MotionEvent.ACTION_CANCEL:              case MotionEvent.ACTION_UP:                  if (viewParent != null) {                      viewParent.requestDisallowInterceptTouchEvent(false);                  }                  break;          }          mViewDragHelper.processTouchEvent(ev);          return true;      }        @Override      protected void onLayout(boolean changed, int l, int t, int r, int b) {          super.onLayout(changed, l, t, r, b);          int measureHeight = mBottomView.getMeasuredHeight();          int measureWidth = mBottomView.getMeasuredWidth();          mBottomView.layout(mWidth - measureWidth, (mHeight - measureHeight) / 2, mWidth, mHeight + measureHeight / 2);//靠右边界垂直居中          if (mState == OPEN) {              mTopView.layout(-measureWidth, 0, mTopView.getMeasuredWidth() - measureWidth, mTopView.getMeasuredHeight());          }      }        @Override      protected void onSizeChanged(int w, int h, int oldw, int oldh) {          super.onSizeChanged(w, h, oldw, oldh);          mWidth = w;          mHeight = h;      }        @Override      protected void onFinishInflate() {          super.onFinishInflate();          if (getChildCount() != 2) {              throw new IllegalStateException("only and should contain two child view");          }          View bottomView = getChildAt(0);          if (!(bottomView instanceof ViewGroup)) {              throw new IllegalStateException("sideslip menu should be contained by a viewgroup");          }          mBottomView = bottomView;          mTopView = getChildAt(1);      }          //回滚到左边(只能在onViewReleased里使用该方法)      private void scrollToLeftEdge() {          mViewDragHelper.settleCapturedViewAt(-mBottomView.getMeasuredWidth(), 0);          invalidate();          mState = OPEN;          if (mSwipeListener != null) {              mSwipeListener.onOpenListener(this);          }      }        //回滚到右边(只能在onViewReleased里使用该方法)      private void scrollToRightEdge() {          mViewDragHelper.settleCapturedViewAt(0, 0);          invalidate();          mState = CLOSE;      }        public void smoothClose() {          mViewDragHelper.smoothSlideViewTo(mTopView, 0, 0);          invalidate();          mState = CLOSE;      }        public int getState() {          return mState;      }        public void setState(int state) {          mState = state;          invalidate();      }        public interface SwipeListener {          void onOpenListener(SwipeLayout swipeLayout);      }        public void setSwipeListener(SwipeListener mSwipeListener) {          this.mSwipeListener = mSwipeListener;      }      }</code></pre>    <p>效果图</p>    <p style="text-align:center"><img src="https://simg.open-open.com/show/fad2433bea3d3001d6425edd38cb6a14.gif"></p>    <p style="text-align:center">SwipeLayout.gif</p>    <p> </p>    <p> </p>