android实现简单拍照功能

package com.example.testsimple;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Date;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Environment;
import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.PixelFormat;
import android.hardware.Camera;
import android.text.format.DateFormat;
import android.util.Log;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
public class MainActivity extends Activity {
 private SurfaceView surfaceView; 
  private SurfaceHolder surfaceHolder; 
  private Camera camera; 
  private File picture; 
  private Button btnSave; 
  private final static String TAG = "CameraActivity"; 
  private ImageView open_picIcon;
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    /* Intent intent=new Intent(MainActivity.this,MyCameraActivity.class);
    startActivity(intent);
    finish();*/
    setupViews();
  }
  private void setupViews(){ 
    surfaceView = (SurfaceView) findViewById(R.id.camera_preview); // Camera interface to instantiate components 
    surfaceHolder = surfaceView.getHolder(); // Camera interface to instantiate components 
    surfaceHolder.addCallback(surfaceCallback); // Add a callback for the SurfaceHolder 
    surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); 
    btnSave = (Button) findViewById(R.id.save_pic);
    open_picIcon=(ImageView) findViewById(R.id.open_picIcon);
    btnSave.setOnClickListener(new OnClickListener() { 
      @Override 
      public void onClick(View v) {
       surfaceView.setVisibility(View.VISIBLE);
       open_picIcon.setVisibility(View.GONE);
        takePic(); 
      } 
    }); 
  } 
  @Override 
  public boolean onKeyDown(int keyCode, KeyEvent event) { 
    if (keyCode == KeyEvent.KEYCODE_CAMERA 
        || keyCode == KeyEvent.KEYCODE_SEARCH) { 
      takePic(); 
      return true; 
    } 
    return super.onKeyDown(keyCode, event); 
  } 
  private void takePic() { 
    camera.stopPreview();// stop the preview 
    camera.takePicture(null, null, pictureCallback); // picture 
  } 
  // Photo call back 
  Camera.PictureCallback pictureCallback = new Camera.PictureCallback() { 
    //@Override 
    public void onPictureTaken(byte[] data, Camera camera) { 
      new SavePictureTask().execute(data); 
      camera.startPreview(); 
    } 
  }; 
  // save pic 
  class SavePictureTask extends AsyncTask<byte[], String, String> { 
    @Override 
    protected String doInBackground(byte[]... params) { 
      String fname = DateFormat.format("yyyyMMddhhmmss", new Date()).toString()+".jpg"; 
      Log.i(TAG, "fname="+fname+";dir="+Environment.getExternalStorageDirectory()); 
      //picture = new File(Environment.getExternalStorageDirectory(),fname);// create file 
      picture = new File(Environment.getExternalStorageDirectory()+"/images/"+fname); 
      File file= picture.getParentFile();
      if(!file.exists())
           file.mkdir();
      try { 
        FileOutputStream fos = new FileOutputStream(picture.getPath()); // Get file output stream 
        fos.write(params[0]); // Written to the file 
        fos.close();  
      } catch (Exception e) { 
        e.printStackTrace(); 
      } 
      return null; 
    } 
    @Override
    protected void onPostExecute(String result) {
     // TODO Auto-generated method stub
     super.onPostExecute(result);
     Bitmap bitmap=getDiskBitmap(picture.getPath());
     surfaceView.setVisibility(View.GONE);
     open_picIcon.setVisibility(View.VISIBLE);
     open_picIcon.setImageBitmap(bitmap);
    }
  } 
  private Bitmap getDiskBitmap(String pathString) 
  { 
    Bitmap bitmap = null; 
    try 
    { 
      File file = new File(pathString); 
      if(file.exists()) 
      { 
        bitmap = BitmapFactory.decodeFile(pathString); 
      } 
    } catch (Exception e) 
    { 
      // TODO: handle exception 
    } 
    return bitmap; 
  } 
  // SurfaceHodler Callback handle to open the camera, off camera and photo size changes 
  SurfaceHolder.Callback surfaceCallback = new SurfaceHolder.Callback() { 
    public void surfaceCreated(SurfaceHolder holder) { 
      Log.i(TAG, "surfaceCallback===="); 
      camera = Camera.open(); // Turn on the camera 
      try { 
        camera.setPreviewDisplay(holder); // Set Preview 
      } catch (IOException e) { 
        camera.release();// release camera 
        camera = null; 
      } 
    } 
    public void surfaceChanged(SurfaceHolder holder, int format, int width, 
        int height) { 
      Log.i(TAG,"====surfaceChanged"); 
      Camera.Parameters parameters = camera.getParameters(); // Camera parameters to obtain 
      parameters.setPictureFormat(PixelFormat.JPEG);// Setting Picture Format 
//     parameters.set("rotation", 180); // Arbitrary rotation 
      camera.setDisplayOrientation(0); 
      parameters.setPreviewSize(400, 300); // Set Photo Size 
      camera.setParameters(parameters); // Setting camera parameters 
      camera.startPreview(); // Start Preview 
    } 
    public void surfaceDestroyed(SurfaceHolder holder) { 
      Log.i(TAG,"====surfaceDestroyed"); 
      camera.stopPreview();// stop preview 
      camera.release(); // Release camera resources 
      camera = null; 
    } 
  }; 
}