Android提高第十九篇之"多方向"抽屉

本文来自http://blog.youkuaiyun.com/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！