Android提高第十九篇之 多方向 抽屜

摘自blog.csdn.net/hellogv

       在android上要實作類別似Launch的抽屜效果，大家一定首先會想起SlidingDrawer。SlidingDrawer是android官方控制項之一，本文的主角不是它，而是民間的控制項工具集合~~~android-misc-widgets。android-misc-widgets裡麵包含幾個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工程地址：-widgets/http://code.google.com/p/android-misc，工程代碼中Panel的示範效果如下：

 

       這個Panel控制項可以輕易實現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 panels 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，並且也同樣實現了OnClickListener的功能，可以把原Panel的OnClickListener給刪掉了！