Android提高第十九篇之"多方向"抽屉

 

本文来自http://blog.csdn.net/hellogv/ ，引用必须注明出处！

       在android上要实现类似Launch的抽屉效果，大家一定首先会想起SlidingDrawer。SlidingDrawer是android官方控件之一，本文的主角不是它，而是民间的控件工具集合~~~android-misc-widgets。android-misc-widgets里面包含几个widget：Panel、SmoothButton、Switcher、VirtualKeyboard,还有一些动画特效，本文主要介绍抽屉容器Panel的用法。android-misc-widgets的google工程地址：-widgets/http://code.google.com/p/android-misc，工程代码中Panel的演示效果如下：

       这个Panel控件可以轻易实现不同方向的抽屉效果，比SlidingDrawer有更强的扩展性！

       在多次使用Panel的过程中，发现Panel有个bug，会间断性出现“闪烁”，也就是在onTouchListener里面的触发ACTION_DOWN后，抽屉瞬间弹出然后瞬间回收(版本日期为Feb 3, 2009)。把原Panel的OnTouchListener，即以下代码：

OnTouchListener touchListener = new OnTouchListener() {  
    int initX;  
    int initY;  
    boolean setInitialPosition;  
    public boolean onTouch(View v, MotionEvent event) {  
        if (mState == State.ANIMATING) {  
            // we are animating   
            return false;  
        }  
/           Log.d(TAG, "state: " + mState + " x: " + event.getX() + " y: " + event.getY());  
        int action = event.getAction();  
        if (action == MotionEvent.ACTION_DOWN) {  
            if (mBringToFront) {  
                bringToFront();  
            }  
            initX = 0;  
            initY = 0;  
            if (mContent.getVisibility() == GONE) {  
                // since we may not know content dimensions we use factors here   
                if (mOrientation == VERTICAL) {  
                    initY = mPosition == TOP? -1 : 1;  
                } else {  
                    initX = mPosition == LEFT? -1 : 1;  
                }  
            }  
            setInitialPosition = true;  
        } else {  
            if (setInitialPosition) {  
                // now we know content dimensions, so we multiply factors...   
                initX *= mContentWidth;  
                initY *= mContentHeight;  
                // ... and set initial panel's position   
                mGestureListener.setScroll(initX, initY);  
                setInitialPosition = false;  
                // for offsetLocation we have to invert values   
                initX = -initX;  
                initY = -initY;  
            }  
            // offset every ACTION_MOVE & ACTION_UP event    
            event.offsetLocation(initX, initY);  
        }  
        if (!mGestureDetector.onTouchEvent(event)) {  
            if (action == MotionEvent.ACTION_UP) {  
                // tup up after scrolling   
                post(startAnimation);  
            }  
        }  
        return false;  
    }  
};  

替换为：

OnTouchListener touchListener = new OnTouchListener() {  
    float touchX, touchY;  
  
    public boolean onTouch(View v, MotionEvent event) {  
        if (mState == State.ANIMATING) {  
            // we are animating   
            return false;  
        }  
  
        int action = event.getAction();  
        if (action == MotionEvent.ACTION_DOWN) {  
            if (mBringToFront) {  
                bringToFront();  
            }  
            touchX = event.getX();  
            touchY = event.getY();  
        }  
  
        if (!mGestureDetector.onTouchEvent(event)) {  
            if (action == MotionEvent.ACTION_UP) {  
                // tup up after scrolling   
                int size = (int) (Math.abs(touchX - event.getX()) + Math  
                        .abs(touchY - event.getY()));  
  
                if (size == mContentWidth || size == mContentHeight) {  
                    mState = State.ABOUT_TO_ANIMATE;  
                    //Log.e("size", String.valueOf(size));   
                    //Log.e(String.valueOf(mContentWidth),String.valueOf(mContentHeight));   
                }  
  
                post(startAnimation);  
            }  
        }  
        return false;  
    }  
};  

即可修复这个bug，并且也同样实现了OnClickListener的功能，可以把原Panel的OnClickListener给删掉了！