说起在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，但是本文的主角并不是它，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的演示效果如下所示：
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加以替换，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！
希望本文所述实例对于大家进行Android项目开发能有所帮助。