Android实现滑动侧边栏

package com.example.test;  import android.content.Context; import android.view.MotionEvent; import android.view.View; import android.view.ViewGroup; import android.widget.Scroller;  public class SlidingMenu extends ViewGroup {   private static final String TAG = SlidingMenu.class.getName();   private enum Scroll_State {   Scroll_to_Open, Scroll_to_Close;  }   private Scroll_State state;  private int mMostRecentX;  private int downX;  private boolean isOpen = false;   private View menu;  private View mainView;   private Scroller mScroller;   private OnSlidingMenuListener onSlidingMenuListener;   public SlidingMenu(Context context, View main, View menu) {   super(context);   // TODO Auto-generated constructor stub   setMainView(main);   setMenu(menu);   init(context);  }   private void init(Context context) {   mScroller = new Scroller(context);  }   @Override  protected void onLayout(boolean arg0, int l, int t, int r, int b) {   // TODO Auto-generated method stub   mainView.layout(l, t, r, b);   menu.layout(-menu.getMeasuredWidth(), t, 0, b);  }   public void setMainView(View view) {   mainView = view;   addView(mainView);  }   public void setMenu(View view) {   menu = view;   addView(menu);  }   @Override  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {   // TODO Auto-generated method stub   super.onMeasure(widthMeasureSpec, heightMeasureSpec);   mainView.measure(widthMeasureSpec, heightMeasureSpec);   menu.measure(widthMeasureSpec - 150, heightMeasureSpec);  }   @Override  public boolean onTouchEvent(MotionEvent event) {   switch (event.getAction()) {   case MotionEvent.ACTION_DOWN:    mMostRecentX = (int) event.getX();    downX = (int) event.getX();    break;   case MotionEvent.ACTION_MOVE:    int moveX = (int) event.getX();    int deltaX = mMostRecentX - moveX;    // 如果在菜单打开时向右滑动及菜单关闭时向左滑动不会触发Scroll事件    if ((!isOpen && (downX - moveX) < 0)      || (isOpen && (downX - moveX) > 0)) {     scrollBy(deltaX / 2, 0);    }    mMostRecentX = moveX;    break;   case MotionEvent.ACTION_UP:    int upX = (int) event.getX();    int dx = upX - downX;    if (!isOpen) {// 菜单关闭时     // 向右滑动超过menu一半宽度才会打开菜单     if (dx > menu.getMeasuredWidth() / 3) {      state = Scroll_State.Scroll_to_Open;     } else {      state = Scroll_State.Scroll_to_Close;     }    } else {// 菜单打开时     // 当按下时的触摸点在menu区域时，只有向左滑动超过menu的一半，才会关闭     // 当按下时的触摸点在main区域时，会立即关闭     if (downX < menu.getMeasuredWidth()) {      if (dx < -menu.getMeasuredWidth() / 3) {       state = Scroll_State.Scroll_to_Close;      } else {       state = Scroll_State.Scroll_to_Open;      }     } else {      state = Scroll_State.Scroll_to_Close;     }    }    smoothScrollto();    break;   default:    break;   }   return true;  }   private void smoothScrollto() {   int scrollx = getScrollX();   switch (state) {   case Scroll_to_Close:    mScroller.startScroll(scrollx, 0, -scrollx, 0, 500);    if (onSlidingMenuListener != null && isOpen) {     onSlidingMenuListener.close();    }    isOpen = false;    break;   case Scroll_to_Open:    mScroller.startScroll(scrollx, 0,      -scrollx - menu.getMeasuredWidth(), 0, 500);    if (onSlidingMenuListener != null && !isOpen) {     onSlidingMenuListener.close();    }    isOpen = true;    break;   default:    break;   }  }   @Override  public void computeScroll() {   if (mScroller.computeScrollOffset()) {    scrollTo(mScroller.getCurrX(), 0);   }   invalidate();  }   public void open() {   state = Scroll_State.Scroll_to_Open;   smoothScrollto();  }   public void close() {   state = Scroll_State.Scroll_to_Close;   smoothScrollto();  }   public boolean isOpen() {   return isOpen;  }   public void setOnSlidingMenuListener(    OnSlidingMenuListener onSlidingMenuListener) {   this.onSlidingMenuListener = onSlidingMenuListener;  }   public interface OnSlidingMenuListener {   public void open();    public void close();  }  } 

package com.example.test;  import android.os.Bundle; import android.support.v4.app.FragmentActivity; import android.view.LayoutInflater; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button;  public class MainActivity extends Activity {   private Button openButton;  private Button closeButton;  private SlidingMenu mSlidingMenu;   @Override  protected void onCreate(Bundle savedInstanceState) {   super.onCreate(savedInstanceState);   mSlidingMenu = new SlidingMenu(this, LayoutInflater     .from(this).inflate(R.layout.fragment1, null), LayoutInflater     .from(this).inflate(R.layout.fragment2, null));   setContentView(mSlidingMenu);//注意setContentView需要换为我们的SlidingMenu   openButton = (Button) findViewById(R.id.button1);   closeButton = (Button) findViewById(R.id.button_close);   openButton.setOnClickListener(new OnClickListener() {        @Override    public void onClick(View arg0) {     // TODO Auto-generated method stub     mSlidingMenu.open();    }   });   closeButton.setOnClickListener(new OnClickListener() {        @Override    public void onClick(View arg0) {     // TODO Auto-generated method stub     mSlidingMenu.close();    }   });  }  }