Android自动聚焦、摄像头拍照、缩放至标准大小的完整实现

为什么把自动聚焦放在前面呢？因为前文http://blog.csdn.net/yanzi1225627/article/details/7738736已经实现了拍照功能，且网上拍照的源码例子很多，自动聚焦很多人写的很简单，但结果发现不中。我这里就总结下，我的自动聚焦的实现。

手机华为U9200，

android4.0.3,

预览的参数：myParameters.setPreviewSize(1280, 720）

图片参数：myParameters.setPictureSize(2048, 1152); //1280, 720

图片最终尺寸:宽600 * 高800

（关于setPreviewSize和setPictureSize的问题可以参照我以前的文章http://blog.csdn.net/yanzi1225627/article/details/7738736）

参照http://www.cnblogs.com/liuan/archive/2012/01/10/2318300.html，上面的思路是弄了一个定时器来进行自动聚焦，但发现根本不中，一按拍照程序就挂掉。而且由于定时器一直在重复循环，相机就在那聚焦来聚焦去，也就是一下清晰一下又模糊了。后来我把程序改成，当拍照后把定时器关闭掉发现还是不中。经反复实验，终于成功。南无阿弥陀佛，本着我为人人，人人为我。将源码贴在此处：

第一，布局文件。里面有一个surfaceview和三个按钮，分别是预览、拍照、保存。

<?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" >

<SurfaceView
    android:id="@+id/mySurfaceView"  
    android:layout_width="fill_parent"
    android:background="#D1EEEE"
    android:layout_height="800px"
    android:gravity="center" />

<LinearLayout
    android:id="@+id/LinearLayout01"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal"
    android:paddingTop="20dip"    
    android:orientation="horizontal" >

    <Button
        android:id="@+id/btnPreview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        
        android:text="预览" />

    <Button
        android:id="@+id/btnPhoto"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="拍照" />

    <Button
        android:id="@+id/btnSave"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="保存" />

</LinearLayout>

</LinearLayout>

第2，源程序：

package yan.guoqi.testphoto;

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Timer;
import java.util.TimerTask;

import android.app.Activity;
import android.app.AlertDialog;
import android.app.AlertDialog.Builder;
import android.content.DialogInterface;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.PixelFormat;
import android.hardware.Camera;
import android.hardware.Camera.PictureCallback;
import android.hardware.Camera.ShutterCallback;
import android.os.Bundle;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.Window;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.Toast;

public class TestPhotoActivity extends Activity implements SurfaceHolder.Callback{
    /** Called when the activity is first created. */
	private static final  String TAG = "yan:";
	SurfaceView mySurfaceView = null;
	SurfaceHolder mySurfaceHolder = null;
	Button btnPreview = null;
	Button btnPhoto = null;
	Button btnSave = null;
	Camera myCamera = null;
	Camera.Parameters myParameters;
	boolean isView = false;
	Bitmap bm;
	String savePath = "/mnt/sdcard/testPhoto/";
	int cntSave = 0;
	private Camera.AutoFocusCallback mAutoFocusCallback;
	//private Camera.PreviewCallback mPreviewCallback;
	private Timer mTimer;
	private TimerTask mTimerTask;
    @Override
    public void onCreate(Bundle savedInstanceState) {
    	super.onCreate(savedInstanceState);
    	//璁剧疆鍏ㄥ睆鏃犳爣棰?    	requestWindowFeature(Window.FEATURE_NO_TITLE);
    	int flag = WindowManager.LayoutParams.FLAG_FULLSCREEN;
    	Window myWindow = this.getWindow();
    	myWindow.setFlags(flag, flag);
    	setContentView(R.layout.main); //璁剧疆甯冨眬
    	mySurfaceView = (SurfaceView)findViewById(R.id.mySurfaceView);
    	mySurfaceView.setZOrderOnTop(true);
    	mySurfaceHolder = mySurfaceView.getHolder();
    	mySurfaceHolder.setFormat(PixelFormat.TRANSLUCENT);
    	btnPreview = (Button)findViewById(R.id.btnPreview);
    	btnPhoto = (Button)findViewById(R.id.btnPhoto);
    	btnSave = (Button)findViewById(R.id.btnSave);
    	if(!isFolderExist(savePath)) //濡傛灉鍒涘缓鏂囦欢澶瑰け璐?    	{
    		AlertDialog.Builder alertDialog = new Builder(TestPhotoActivity.this);
    		alertDialog.setTitle("閿欒");
    		alertDialog.setMessage("鍥剧墖淇濆瓨鏂囦欢澶瑰垱寤哄け璐ワ紒");
    		alertDialog.setPositiveButton("纭畾", new DialogInterface.OnClickListener() {
				
				public void onClick(DialogInterface dialog, int which) {
					// TODO Auto-generated method stub
					dialog.dismiss();
					TestPhotoActivity.this.finish();
				}
			});
    		alertDialog.show();
    	}
    	else
    		Toast.makeText(TestPhotoActivity.this,
    				"鎮ㄧ殑鐓х墖灏嗕繚瀛樺湪锛? + savePath,
    				Toast.LENGTH_SHORT).show();
    	mySurfaceHolder.addCallback(this);
    	mySurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    	mAutoFocusCallback = new Camera.AutoFocusCallback() {
			
			public void onAutoFocus(boolean success, Camera camera) {
				// TODO Auto-generated method stub
				if(success){
					myCamera.setOneShotPreviewCallback(null);
		    		Toast.makeText(TestPhotoActivity.this,
		    				"鑷姩鑱氱劍鎴愬姛锛?,
		    				Toast.LENGTH_SHORT).show();
				}
					
			}
		}; 
		mTimer = new Timer();
		mTimerTask = new CameraTimerTask();
		//mTimer.schedule(mTimerTask, 0, 500);
		
    	btnPreview.setOnClickListener(new BtnListener());
    	btnPhoto.setOnClickListener(new BtnListener());
    	btnSave.setOnClickListener(new BtnListener());
    	
    }
    ShutterCallback myShutterCallback = new ShutterCallback() {
		
		public void onShutter() {
			// TODO Auto-generated method stub
			
		}
	};
	PictureCallback myRawCallback = new PictureCallback() {
		
		public void onPictureTaken(byte[] data, Camera camera) {
			// TODO Auto-generated method stub
			
		}
	};
	PictureCallback myjpegCalback = new PictureCallback() {
		
		public void onPictureTaken(byte[] data, Camera camera) {
			// TODO Auto-generated method stub
			Log.i(TAG, "onPictureTaken........");
			bm = BitmapFactory.decodeByteArray(data, 0, data.length);
			isView = false;
			myCamera.stopPreview();
			myCamera.release();
			myCamera = null;
			isView = false;
			
		}
	};
    class BtnListener implements OnClickListener{

		public void onClick(View v) {
			// TODO Auto-generated method stub
			switch(v.getId()){
			case R.id.btnPreview:
				Toast.makeText(TestPhotoActivity.this,
						"鎮ㄦ寜浜嗛瑙堟寜閽?,
						Toast.LENGTH_SHORT).show();
				initCamera();
				break;
			case R.id.btnPhoto:
				if(isView && myCamera!=null){	
										
					myCamera.takePicture(myShutterCallback, myRawCallback, myjpegCalback);
				}
				else
					Toast.makeText(TestPhotoActivity.this, "璇峰厛棰勮鐒跺悗鎷嶇収锛?, Toast.LENGTH_SHORT).show();				
				break;
			case R.id.btnSave:
                  if(bm == null)
                  {
                	  Toast.makeText(TestPhotoActivity.this, "璇锋媿鎽勬垚鍔熷悗鍐嶄繚瀛橈紒锛侊紒", Toast.LENGTH_SHORT).show();
                	  return;
                  }
      			int b =0, c=1;
    			File fTest = new File(savePath + b + c + ".JPG");
    			while(fTest.exists()){
    				if(c==9){
    					b++;
    					c = 0;
    				}
    				else
    					c++;
    				if(b==9){
    					b = 0;
    					Toast.makeText(TestPhotoActivity.this, "姝ゅ織鎰胯€呮牱鏈暟鐩凡瓒呰繃100锛?, 
    							Toast.LENGTH_SHORT).show();
    				}
    				fTest = new File(savePath + b + c + ".JPG");
    			}
    			try {
					FileOutputStream fout = new FileOutputStream(fTest);
					BufferedOutputStream bos = new BufferedOutputStream(fout);
					Bitmap mBitmap = Bitmap.createScaledBitmap(bm, 600, 800, false);
					mBitmap.compress(Bitmap.CompressFormat.JPEG, 100, bos);
					//bm.compress(Bitmap.CompressFormat.JPEG, 100, bos);
					bos.flush();
					bos.close();
					cntSave++;
					Toast.makeText(TestPhotoActivity.this, "鎮ㄦ媿鐨勭"+cntSave+"寮爌icture淇濆瓨鎴愬姛锛佺紪鍙凤細"+ b + c,
							Toast.LENGTH_SHORT).show();
					
				}  catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
					Toast.makeText(TestPhotoActivity.this,
							"淇濆瓨澶辫触",
							Toast.LENGTH_SHORT).show();
				}
    			
                	  
				break;
				default:									
				
			}			
		}    	
    }
    
	public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) {
		// TODO Auto-generated method stub
		
	}

	public void surfaceCreated(SurfaceHolder arg0) {
		// TODO Auto-generated method stub
		
	}

	public void surfaceDestroyed(SurfaceHolder arg0) {
		// TODO Auto-generated method stub
		
		
	}
	
	//鍒濆鍖栨憚鍍忓ご
	public void initCamera()
	{
		if(myCamera == null && !isView)
		{
			myCamera = Camera.open();
			Log.i(TAG, "camera.open");
		}
		if(myCamera != null && !isView) {
			try {
				
					myParameters = myCamera.getParameters();
					myParameters.setPictureFormat(PixelFormat.JPEG);
					myParameters.setPreviewSize(1280, 720);
					//myParameters.setFocusMode("auto");
					
					myParameters.setPictureSize(2048, 1152); //1280, 720
					
					myParameters.set("rotation", 90);
					myCamera.setDisplayOrientation(90);
					myCamera.setParameters(myParameters);
					myCamera.setPreviewDisplay(mySurfaceHolder);
					myCamera.startPreview();
					isView = true;
					myCamera.autoFocus(mAutoFocusCallback);
			
			} catch (Exception e) {
				// TODO: handle exception
				e.printStackTrace();
				Toast.makeText(TestPhotoActivity.this, "鍒濆鍖栫浉鏈洪敊璇?,
						Toast.LENGTH_SHORT).show();
			}
		}
		
	}
	class CameraTimerTask extends TimerTask{

		@Override
		public void run() {
			// TODO Auto-generated method stub
			if(myCamera != null)
			{
				myCamera.autoFocus(mAutoFocusCallback);
			}
			
		}
		
	}
	//鍒ゆ柇鏂囦欢澶规槸鍚﹀瓨鍦紝濡傛灉涓嶅瓨鍦ㄥ垯鍒涘缓涓€涓?		public boolean isFolderExist(String folderPath){
			boolean result = false;
			File f = new File(folderPath);
			if(!f.exists()){
				if(f.mkdir()){
					result = true;
				}
				else
					result = false;
			}
			else
				result = true;
			
			return result;
		}
}

自动聚焦部分，核心的代码有，构造函数里的

private Camera.AutoFocusCallback mAutoFocusCallback;
mAutoFocusCallback = new Camera.AutoFocusCallback() {

public void onAutoFocus(boolean success, Camera camera) {
// TODO Auto-generated method stub
if(success){
myCamera.setOneShotPreviewCallback(null);
Toast.makeText(TestPhotoActivity.this,
"自动聚焦成功",Toast.LENGTH_SHORT).show();
}

}
};
和initCamera里的myCamera.autoFocus(mAutoFocusCallback);调用！

第三，AndroidManifest文件，红线部分是添加的对摄像头操作、sd存储的权限许可。

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="yan.guoqi.testphoto"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="15" />
<!-- 鍦╯d鍗′腑鍒涘缓鍜屽垹闄ゆ枃浠剁殑鏉冮檺 -->
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />
<!-- 鍦╯d鍗′腑鍐欏叆鏁版嵁鐨勬潈闄?-->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<!-- 浣跨敤鎷嶇収鐨勬潈闄?-->
<uses-permission android:name="android.permission.CAMERA" />

<uses-feature android:name="android.hardware.camera" />

<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<activity
android:name=".TestPhotoActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>

</manifest>

上两张效果图，来看下摄像头相同的previewSize、pictureSize下，自动对焦前后的差别：

效果差别不是一般的大啊！

1，上面的源程序里mTimer、mTimerTask等这些是我第一种思路，用定时器来控制聚焦，结果是失败的。碰到这些，大家略过去就行了。

2，这里控制聚焦的核心实现时，在initCamera函数里，执行myCamera.autoFocus(mAutoFocusCallback);自动聚焦这句话！在构造函数里定义了一个mAutoFocusCallback的回调函数变量。还可以在按下拍照按钮后判断当前是否自动聚焦成功，如果聚焦成功再拍照！mAutoFocusCallback里的if（success）就是标示自动聚焦成功

3，网上有很多，只是简单的在构造函数里写一句myCamera.setFocus(null),我真怀疑，这不是坑爹么？反正我这样是没弄成功。

4，程序里的乱码部分是文字，由于从linux下拷出来就成乱码了，大家不用太关心，都是些提示性的话。

5，另外还要交代一下，自动聚焦这句话一定要在摄像头正常预览的时候调用，否则是没有意义的，程序也会挂掉。

6，我核心的参考文章：

http://www.cnblogs.com/liuan/archive/2012/01/10/2318300.html

http://www.cnblogs.com/skyseraph/archive/2012/03/26/2418665.html

向他们表示感谢！

遗留的问题：

我第一次按下预览按钮后，会进行自动聚焦，并提示自动聚焦成功。如果此时执行拍照--保存--再次预览，则自动聚焦是成功的。 如果我预览后，调整了和拍摄物的距离这时想再次自动聚焦，即连续两次按下预览按钮，怎么第二次就不自动聚焦了呢？？？这是不是和android摄像头内置的属性有关系？

源码下载链接：http://download.csdn.net/detail/yanzi1225627/4538626

----------------------作者yanzi1225627 转载请注明 2012.8.31