Android实现滑动选择控件实例代码

//这里使用dispatchTouchEvent，因为onTouchEvent容易被OnTouchListener截取  @Override  public boolean dispatchTouchEvent(MotionEvent ev) {    LayoutManager manager = getLayoutManager();    //获取第一个和最后一个显示的Item对应的相对Position    if (manager instanceof LinearLayoutManager) {      mFirstVisiblePosition = ((LinearLayoutManager) manager).findFirstVisibleItemPosition();      mLastVisiblePosition = ((LinearLayoutManager) manager).findLastVisibleItemPosition();    }    switch (ev.getAction()) {      case MotionEvent.ACTION_DOWN:        //获取按下时的位置,x,y        int startX = (int) ev.getX();        int startY = (int) ev.getY();        int preX = startX;        mPreY = startY;        mPreFirstVisiblePosition = mFirstVisiblePosition;        mPrePosition = mStartPosition = pointToPosition(startX, startY);        if (mStartPosition > -1) {          //获取当前Item的View          View child = getChildAt(mStartPosition);          if (null != child) {            //获取响应域，一般响应域里面就是一个CheckBox            View tmpCheckBoxContainer = child.findViewWithTag("checkbox_layout");            if (null != tmpCheckBoxContainer && tmpCheckBoxContainer.getVisibility() == VISIBLE) {              mCheckBoxWidth = tmpCheckBoxContainer.getWidth();              //获取响应域的范围，一定要用这种获取绝对位置的方式，不然会受到padding或者是margin的影响              int[] location = new int[2];              tmpCheckBoxContainer.getLocationOnScreen(location);              mCheckBoxX = location[0];              //判断按下的位置是否是在响应域内              if (startX >= mCheckBoxX && startX <= (mCheckBoxX + mCheckBoxWidth)) {                Log.d(LOG_TAG, "dispatchTouchEvent() DOWN mStartPosition: " + mStartPosition);                //设置截取事件的标志位                mIsNeedScrollCheck = true;                //设置为第一次滑动，这是用作判断折返的                mIsFirstMove = true;                setStartCheckBoxState();                //截获Checkbox的点击事件，防止两次选中                return true;              } else {                mIsNeedScrollCheck = false;              }            } else {              mIsNeedScrollCheck = false;              Log.e(LOG_TAG, "dispatchTouchEvent() ", new Throwable("Cannot get CheckBoxContainer!"));            }          } else {            Log.e(LOG_TAG, "dispatchTouchEvent() ", new Throwable("Cannot get item view!"));          }        }        break;      case MotionEvent.ACTION_MOVE:        //获取当前位置        int currentX = (int) ev.getX();        int currentY = (int) ev.getY();        //获取当前的item        int currentPosition = pointToPosition(currentX, currentY);        //判断是否允许滑动选中        if (mIsNeedScrollCheck && -1 != mFirstVisiblePosition && -1 != mLastVisiblePosition && -1 != currentPosition) {          //判断是否在下一个Item的像英语          if ((currentPosition + mFirstVisiblePosition) != (mPrePosition + mPreFirstVisiblePosition) &&              currentX >= mCheckBoxX && currentX <= (mCheckBoxX + mCheckBoxWidth)) {            Log.i(LOG_TAG, "********************************** dispatchTouchEvent() ********************************");            Log.d(LOG_TAG, "dispatchTouchEvent() MOVE mCurrentPosition: " + currentPosition);            Log.d(LOG_TAG, "dispatchTouchEvent() MOVE mFirstVisiblePosition: " + mFirstVisiblePosition);            Log.d(LOG_TAG, "dispatchTouchEvent() MOVE mPrePosition: " + mPrePosition);            Log.d(LOG_TAG, "dispatchTouchEvent() MOVE mPreFirstVisiblePosition: " + mPreFirstVisiblePosition);            Log.i(LOG_TAG, "********************************** dispatchTouchEvent() ********************************");            //折返回来时要改变前一个的Checkbox的状态            if (mIsFirstMove) {              mIsFirstMove = false;              if (currentY >= mPreY) {                mUpOrDown = false;              } else {                mUpOrDown = true;              }            } else {              if ((currentPosition + mFirstVisiblePosition) > (mPrePosition + mPreFirstVisiblePosition) && mUpOrDown) {                changeCheckBoxState(mPrePosition);                mUpOrDown = false;              } else if ((currentPosition + mFirstVisiblePosition) < (mPrePosition + mPreFirstVisiblePosition) && !mUpOrDown) {                changeCheckBoxState(mPrePosition);                mUpOrDown = true;              }            }            changeCheckBoxState(currentPosition);          }          //判断是否是在最后一个item上滑动，如果是则进行自动向下滑动，如果是在第一个上下滑动，则自动向上滑动          //Log.d(LOG_TAG, "dispatchTouchEvent() MOVE: " + (mLastVisiblePosition - mCurrentPosition - mFirstVisiblePosition));          if ((mLastVisiblePosition - mFirstVisiblePosition - currentPosition) < 1 && currentY > mPreY) {            //自动向下滑            Log.d(LOG_TAG, "dispatchTouchEvent() MOVE mCount: " + mCount);            View child = getChildAt(currentPosition);            if (null != child && 0 == mCount % 5) {              scrollToPosition(mLastVisiblePosition + 1);            }            mCount++;          } else if (currentPosition < 2 && currentY < mPreY) {            //自动向上滑            View child = getChildAt(currentPosition);            Log.d(LOG_TAG, "dispatchTouchEvent() MOVE mCount: " + mCount);            //mCount用于降低滑动的频率，频率太快容易滑动的看不清楚            if (null != child && 0 == mCount % 5) {              scrollToPosition(mFirstVisiblePosition - 1);            }            mCount++;          }          mPreY = currentY;          mPrePosition = currentPosition;          mPreFirstVisiblePosition = mFirstVisiblePosition;          return true;        }        break;      case MotionEvent.ACTION_UP:        if (mIsNeedScrollCheck) {          mCount = 0;          return false;        }        break;    }    return super.dispatchTouchEvent(ev);  }

//改变开始的CheckBox状态  private void setStartCheckBoxState() {    View child = getChildAt(mStartPosition);    if (null != child) {      ViewGroup checkBoxContainer = (ViewGroup) child.findViewWithTag("checkbox_layout");      if (null != checkBoxContainer) {        CheckBox checkBox = (CheckBox) checkBoxContainer.getChildAt(0);        if (null != checkBox && checkBox.getVisibility() == VISIBLE) {          checkBox.toggle();        }      }    }  }

//判断当前Item的Position，相对位置  private int pointToPosition(int x, int y) {    Rect frame = mTouchFrame;    if (frame == null) {      mTouchFrame = new Rect();      frame = mTouchFrame;    }    final int count = getChildCount();    for (int i = count - 1; i >= 0; i--) {      final View child = getChildAt(i);      if (child.getVisibility() == View.VISIBLE) {        child.getHitRect(frame);        if (frame.contains(x, y)) {          return i;        }      }    }    return -1;  }

//改变Position的选中状态  public void changeCheckBoxState(int position) {    if (position < 0 || position >= getChildCount()) {      return;    }    View child = getChildAt(position);    if (null != child) {      ViewGroup checkBoxLayout = (ViewGroup) child.findViewWithTag("checkbox_layout");      if (null != checkBoxLayout && checkBoxLayout.getVisibility() == VISIBLE) {        CheckBox checkBox = (CheckBox) checkBoxLayout.getChildAt(0);        if (null != checkBox) {          Log.d(LOG_TAG, "changeCheckBoxState() selectCheckBox: " + position);          //checkBox.performClick();          checkBox.toggle();          //checkBox.setClickable(false);          //checkBox.callOnClick();        }      }    }  }