Android 照相机打开方法

package gongzibai.co.cc;

import android.app.Activity;
import android.hardware.Camera;
import android.os.Bundle;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class Ex2Activity extends Activity implements SurfaceHolder.Callback {

   Camera mCamera;
   SurfaceView mSurfaceView;
   SurfaceHolder mSurfaceHolder;
   Button mButton1,mButton2;
   boolean isPreview=false;
 /** Called when the activity is first created. */
 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);
  mSurfaceView=(SurfaceView)findViewById(R.id.surfaceView1);
  mButton1=(Button)findViewById(R.id.button1);
  mButton2=(Button)findViewById(R.id.button2);
  mSurfaceHolder=mSurfaceView.getHolder();
  mSurfaceHolder.addCallback(this);
  mSurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
  mButton1.setOnClickListener(new OnClickListener() {
   
   @Override
   public void onClick(View v) {
    // TODO Auto-generated method stub
    
    initCamera();
    
   }
   
   
  

   private void initCamera() {
    // TODO Auto-generated method stub
    
    if (!isPreview) {
     mCamera=Camera.open();
    }
    
    if (mCamera!=null&&!isPreview) {
     try {
      mCamera.setPreviewDisplay(mSurfaceHolder);
      mCamera.startPreview();
     } catch (Exception e) {
      // TODO: handle exception
      e.printStackTrace();
     }
     isPreview=true;
    }
   }
  });
  
  
  mButton2.setOnClickListener(new OnClickListener() {
   
   @Override
   public void onClick(View v) {
    // TODO Auto-generated method stub
    if (mCamera!=null&&isPreview) {
     mCamera.stopPreview();
     mCamera.release();
     mCamera=null;
     isPreview=false;
    }
    
   }
  });
  

 }

 @Override
 public void surfaceChanged(SurfaceHolder holder, int format, int width,
   int height) {
  // TODO Auto-generated method stub
  
 }

 @Override
 public void surfaceCreated(SurfaceHolder holder) {
  // TODO Auto-generated method stub
  
 }

 @Override
 public void surfaceDestroyed(SurfaceHolder holder) {
  // TODO Auto-generated method stub
  
 }
}