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);}@Overridepublic 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 @Overridepublic 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 @Overridepublic void onShowPress(MotionEvent e) {}@Overridepublic 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@Overridepublic 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 @Overridepublic void onLongPress(MotionEvent e) {}//Touch了滑动一点距离后，up时触发。@Overridepublic 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> {@Overrideprotected 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]);elsetimes = 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;}@Overrideprotected 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;@Overrideprotected 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: