android自定义实现抽屉SlidingDrawer的功能

最近项目中需要实现上拉功能，首先想到的就是Android本身自带的抽屉SlidingDrawer，最后也实现了不过，出现的问题就是设置背景色问题，handler和content是两个不同的部分，这就造成图片要做成两部分，从而产生两个部分图片看起来不是一个整体，而且我这个上拉功能，里面要实现一个水平滚动功能，而SlidingDrawer还有其他的限制，同时官方给出api 17以后，这个功能已经废弃，所以自己自定这样一个上拉功能是必须的。

这里我是继承LinearLayout同时实现GestureDetector.OnGestureListener来实现上拉功能。下面是代码：

package com.example.test;

import android.content.Context;
import android.os.AsyncTask;
import android.util.AttributeSet;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;

public class PanelBom extends LinearLayout implements GestureDetector.OnGestureListener{

	GestureDetector mGesture = null;
	private boolean isScrolling = false;
	private int MAX_HEIGHT = 80;//拖动的最大高度,当前布局位于父布局下面-80位置，这个仅仅是调试参数，这个变量是动态设置的。
	private float mScrollX; // 滑块滑动距离
	public PanelBom(Context context) {
		super(context);
		init();
	}
	public PanelBom(Context context, AttributeSet attrs) {
		super(context, attrs);
		init();
	}
	//初始化一些参数
	public void init(){
		mGesture = new GestureDetector(this);
		mGesture.setIsLongpressEnabled(false);
		setBackgroundResource(R.drawable.button_bar);
	}
	
	@Override
	public boolean onTouchEvent(MotionEvent event) {
		if (MotionEvent.ACTION_UP == event.getAction() && isScrolling == true) {
			RelativeLayout.LayoutParams layoutParams = (RelativeLayout.LayoutParams)getLayoutParams();
			// 缩回去
			if (layoutParams.bottomMargin < -MAX_HEIGHT / 2) {
				new AsynMove().execute(-20);//负--往下
			} else {
				new AsynMove().execute(20);//正--往上
			}
		}
		return mGesture.onTouchEvent(event);
	}
	//Touch down时触发 
	@Override
	public boolean onDown(MotionEvent e) {
		mScrollX = 0;
		isScrolling = false;
		// 将之改为true，不然事件不会向下传递.
		return true;
	}
	//Touch了还没有滑动时触发 
	@Override
	public void onShowPress(MotionEvent e) {
		
	}
	@Override
	public boolean onSingleTapUp(MotionEvent e) {
		RelativeLayout.LayoutParams layoutParams = (RelativeLayout.LayoutParams) getLayoutParams();
		// 说明在上面，要往下
		if (layoutParams.bottomMargin >= 0) {
			new AsynMove().execute(-20);//负--往下
		} else {
			new AsynMove().execute(20);//正--往上
		}
		return true;
	}
	//Touch了滑动时触发
	@Override
	public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX,
			float distanceY) {
		isScrolling = true;
		mScrollX += distanceY;
		RelativeLayout.LayoutParams layoutParams = (RelativeLayout.LayoutParams)getLayoutParams();
		layoutParams.bottomMargin += mScrollX;
		if (layoutParams.bottomMargin >= 0) {
			isScrolling = false;// 拖过头了不需要再执行AsynMove了
			layoutParams.bottomMargin = 0;
		} else if (layoutParams.bottomMargin <= -MAX_HEIGHT) {
			// 拖过头了不需要再执行AsynMove了
			isScrolling = false;
			layoutParams.bottomMargin = -MAX_HEIGHT;
		}
		setLayoutParams(layoutParams);
		return false;
	}
	//Touch了不移动一直Touch down时触发 
	@Override
	public void onLongPress(MotionEvent e) {
		
	}
	//Touch了滑动一点距离后，up时触发。
	@Override
	public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
			float velocityY) {
		return false;
	}
	//异步更新布局的位置
	class AsynMove extends AsyncTask<Integer, Integer, Void> {
		@Override
		protected Void doInBackground(Integer... params) {
			int times = 0;
			int divi = Math.abs(params[0]);
			if (MAX_HEIGHT % divi == 0)// 整除
				times = MAX_HEIGHT / Math.abs(params[0]);
			else
				times = MAX_HEIGHT / divi + 1;// 有余数

			for (int i = 0; i < times; i++) {
				publishProgress(params[0]);
				try {
					Thread.sleep(divi);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
			}
			return null;
		}
		@Override
		protected void onProgressUpdate(Integer... values) {
			RelativeLayout.LayoutParams layoutParams = (RelativeLayout.LayoutParams) getLayoutParams();
			if (values[0] < 0) {
				layoutParams.bottomMargin = Math.max(layoutParams.bottomMargin + values[0], -MAX_HEIGHT);
			} else {
				layoutParams.bottomMargin = Math.min(layoutParams.bottomMargin + values[0], 0);
			}
			setLayoutParams(layoutParams);
			
			super.onProgressUpdate(values);
		}
	}
}

主界面：

package com.example.test;

import android.app.Activity;
import android.os.Bundle;
import android.widget.RelativeLayout;

public class Main5 extends Activity{

	RelativeLayout Parent;
	PanelBom panelBom;
	RelativeLayout.LayoutParams parentParams;
	RelativeLayout.LayoutParams paneBomParams;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		Parent = new RelativeLayout(getApplicationContext());
		panelBom = new PanelBom(getApplicationContext());
		parentParams = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.MATCH_PARENT);
		paneBomParams = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, 150);
		paneBomParams.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM);
		paneBomParams.bottomMargin = -80;
		Parent.addView(panelBom, paneBomParams);
		setContentView(Parent, parentParams);
	}

}

实现的效果是：

拖拉，点击实现上拉功能，效果图如下: