camera源码设置条，自己写了个类，具有其主要功能，同样有switcher改进

类代码：

/*
 * Copyright (C) 2009 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.android.bar;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.animation.AnimationUtils;
import android.widget.ImageView;
/**
 * A widget which switchs between the {@code Camera} and the {@code VideoCamera}
 * activities.
 */
public class SetSeekBar extends ImageView implements View.OnTouchListener 
{
    @SuppressWarnings("unused")
    private static final String TAG = "SetSeekBar";
    
    /** A callback to be called when the user wants to switch activity. */
    public interface OnSwitchListener 
    {
        // Returns true if the listener agrees that the switch can be changed.
        public boolean onSwitchChanged(SetSeekBar source, int index);
    }
   
    private int mNumber = 0;
   
    private OnSwitchListener mListener;
    
   
    int drawableHeight = 0;
    int thumbHeight = 0;
    int positionIndex = 0;
    public SetSeekBar(Context context, AttributeSet attrs) 
    {    	
        super(context, attrs);
//        Drawable drawable = getDrawable();
//        drawableHeight = drawable.getIntrinsicHeight();
        drawableHeight = 240;
    }
   
    //the thumb position number
    public void setNumber(int number){
    	
        mNumber = number; 
        thumbHeight = drawableHeight/mNumber;
        Log.i(TAG,"thumbHeight = "+thumbHeight);
    }
    
    public int getNumber(){
    	
    	return mNumber;
    }
    // Try to change the switch position. (The client can veto it.)
    //private void tryToSetSwitch(boolean onOff) 
   
    public void setOnSwitchListener(OnSwitchListener listener) 
    {
        mListener = listener;
    }
    @Override
    public boolean onTouchEvent(MotionEvent event) 
    {
        if (!isEnabled()) 
        	return false;
        
        switch (event.getAction()) 
        {
            case MotionEvent.ACTION_DOWN: 
            	Log.i("TAG","ACTION_DOWN");
//                setPressed(true);
                setPosition(event);
                trackTouchEvent(event);
                break;
            case MotionEvent.ACTION_MOVE:
                trackTouchEvent(event);
                break;
            case MotionEvent.ACTION_UP:
                trackTouchEvent(event);
               
//                setPressed(false);
                break;
            case MotionEvent.ACTION_CANCEL:
                
                setPressed(false);
                break;
        }
        return true;
    }
    //the thumb position index
   private void setPosition(MotionEvent event){
	   int x = (int) event.getY(); 
	   positionIndex = getPosition(x);
	   mListener.onSwitchChanged(this, positionIndex);
	   Log.i("TAG","positionIndex = "+getPosition(x));
   }
    private void trackTouchEvent(MotionEvent event) 
    {       
        int x = (int) event.getY();
        if(positionIndex != getPosition(x)){
        	Log.i("TAG","positionIndex = "+getPosition(x));
        	positionIndex = getPosition(x);
        	mListener.onSwitchChanged(this, positionIndex);
        }
    }
    
    private int getPosition(int x){
    	for(int i=1;i<=mNumber;i++){
    		if(x < thumbHeight*i)
    			return i;
    	}
		return mNumber;
    }

    // Consume the touch events for the specified view.
    public void addTouchView(View v) 
    {
        v.setOnTouchListener(this);
    }
    // This implements View.OnTouchListener so we intercept the touch events
    // and pass them to ourselves.
    public boolean onTouch(View v, MotionEvent event) 
    {
        onTouchEvent(event);
        return true;
    }
}

使用：

<com.android.bar.SetSeekBar
android:id="@+id/bar"
android:layout_width="40dip"
android:layout_height="240dip"
android:background="@drawable/seek_bg"
android:layout_alignParentRight="true"
android:layout_marginRight="30dip"
/>

SetSeekBar indicatorBar = (SetSeekBar)findViewById(R.id.bar);
indicatorBar.setNumber(4);
indicatorBar.setOnSwitchListener(new OnSwitchListener(){
public boolean onSwitchChanged(SetSeekBar source, int index) {
//your code
return true;
}

});