Android提高第十九篇之"多方向"抽屜

本文來自http://blog.csdn.net/hellogv/ ，引用必須注明出處！

       在android上要實作類似Launch的抽屜效果，大家一定首先會想起SlidingDrawer。SlidingDrawer是android官方控件之一，本文的主角不是它，而是民間的控件工具集合~~~android-misc-widgets。android-misc-widgets裡面包含幾個widget：Panel、SmoothButton、Switcher、VirtualKeyboard,還有一些動畫特效，本文主要介紹抽屜容器Panel的用法。android-misc-widgets的google工程位址：-widgets/http://code.google.com/p/android-misc，工程代碼中Panel的示範效果如下：

       這個Panel控件可以輕易實作不同方向的抽屜效果，比SlidingDrawer有更強的擴充性！

       在多次使用Panel的過程中，發現Panel有個bug，會間斷性出現“閃爍”，也就是在onTouchListener裡面的觸發ACTION_DOWN後，抽屜瞬間彈出然後瞬間回收(版本日期為Feb 3, 2009)。把原Panel的OnTouchListener，即以下代碼：

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;

}

};

替換為：

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;

}

};

即可修複這個bug，并且也同樣實作了OnClickListener的功能，可以把原Panel的OnClickListener給删掉了！