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