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);                }            }        }  

    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);            }                }