Android提高第十九篇之"多方向"抽屉--转

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：

[java] view plaincopyprint?

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：

[java] view plaincopyprint?

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！