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; 
} 
}; 
}