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" /