Android实现拍照功能

package org.winplus.camera; 
 
import java.io.File; 
import java.io.FileOutputStream; 
import java.io.IOException; 
import java.util.Date; 
 
import android.app.Activity; 
import android.content.pm.ActivityInfo; 
import android.graphics.PixelFormat; 
import android.hardware.Camera; 
import android.os.AsyncTask; 
import android.os.Bundle; 
import android.os.Environment; 
import android.text.format.DateFormat; 
import android.util.Log; 
import android.view.KeyEvent; 
import android.view.SurfaceHolder; 
import android.view.SurfaceView; 
import android.view.View; 
import android.view.Window; 
import android.view.View.OnClickListener; 
import android.widget.Button; 
 
public class CameraDemoActivity extends Activity{ 
 
 private final static String TAG = "CameraActivity"; 
 private SurfaceView surfaceView; 
 private SurfaceHolder surfaceHolder; 
 private Camera camera; 
 private File picture; 
 private Button btnSave; 
  
 @Override 
 public void onCreate(Bundle savedInstanceState) { 
  super.onCreate(savedInstanceState); 
  setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT); 
  this.requestWindowFeature(Window.FEATURE_NO_TITLE); 
  setContentView(R.layout.main); 
  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); 
   
  btnSave.setOnClickListener(new OnClickListener() { 
    
   @Override 
   public void onClick(View v) { 
    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()+"/"+fname); 
    
   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; 
  } 
 } 
 
 // 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; 
  } 
 }; 
} 

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
 android:layout_width="fill_parent" 
 android:layout_height="fill_parent" 
 android:orientation="vertical" > 
 
 <android.view.SurfaceView 
  android:id="@+id/camera_preview" 
  android:layout_width="800dip" 
  android:layout_height="600dip" 
  android:layout_alignParentTop="true" 
  android:layout_centerInParent="true" 
  android:layout_gravity="center_vertical|center_horizontal" /> 
 
 <Button 
  android:id="@+id/save_pic" 
  android:layout_width="fill_parent" 
  android:layout_height="wrap_content" 
  android:text="@string/txt_save" /> 
 
</LinearLayout> 

<uses-permission android:name="android.permission.CAMERA" /> 
<uses-feature android:name="android.hardware.camera" /> 
<uses-feature android:name="android.hardware.camera.autofocus" android:required="false" />