Google开源库ZXing的使用
参考文章：http://www.cnblogs.com/keyindex/archive/2011/06/08/2074900.html
简化
在开始前大致介绍一下简化ZXing需要用到各个包 、类的职责。
- CaptureActivity。这个是启动Activity 也就是扫描器（如果是第一安装，它还会跳转到帮助界面）。
- CaptureActivityHandler 解码处理类，负责调用另外的线程进行解码。
- DecodeThread 解码的线程。
- com.google.zxing.client.android.camera 包，摄像头控制包。
- ViewfinderView 自定义的View，就是我们看见的拍摄时中间的框框了。
新建另一个项目
新建另一个项目将启动的Activity命名为CaptureActivity，并导入核心库。项目新建完成后我们打开 CaptureActivity 的布局文件，我这里为main。把里面的XML修改为：
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent" android:layout_height="fill_parent">
<SurfaceView android:id="@+id/preview_view"
android:layout_width="fill_parent" android:layout_height="fill_parent"
android:layout_centerInParent="true"/>
<com.Zxing.Demo.view.ViewfinderView
android:id="@+id/viewfinder_view" android:layout_width="fill_parent"
android:layout_height="fill_parent" android:background="@android:color/transparent"/>
<TextView android:layout_width="wrap_content"
android:id="@+id/txtResult"
android:layout_height="wrap_content" android:text="@string/hello"/>
</FrameLayout>
可以看到在XML里面用到了 ViewfinderView 自定义view 。所以新建一个View 的包，然后把：ViewfinderView 和 ViewfinderResultPointCallback 考到里面（记得对应修改XML里面的包）。
打开 CaptureActivity 覆盖 onCreate 方法：
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
//初始化 CameraManager
CameraManager.init(getApplication());
viewfinderView = (ViewfinderView) findViewById(R.id.viewfinder_view);
txtResult = (TextView) findViewById(R.id.txtResult);
hasSurface =false;
inactivityTimer =new InactivityTimer(this);
}
这里调用到的 CameraManager 类是控制摄像头的包里的类。新建一个camera包把：com.google.zxing.client.android.camera 里面的类全部拷入，另外我把PlanarYUVLuminanceSource也拷入到这个包里面。
在修改的过程中，有很多是关于R 资源的问题，在此我们需要将Values 里面的两个xml资源文件拷入项目中：colos.xml 和ids.xml 。 ctrl+b 一下看看error 是不是少了很多。在CameraManager中有些地方需要用到项目的配置，这里需要把配置直接写入代码中：
<uses-permission android:name="android.permission.CAMERA"></uses-permission> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission> <uses-feature android:name="android.hardware.camera"/> <uses-feature android:name="android.hardware.camera.autofocus"/> <uses-permission android:name="android.permission.VIBRATE"/> <uses-permission android:name="android.permission.FLASHLIGHT"/>当View 和 camera 包里的错误修正完成后，我们继续来看CaptureActivity。
覆盖onResume方法初始化摄像头：
@Override
protected void onResume() {
super.onResume();
SurfaceView surfaceView = (SurfaceView) findViewById(R.id.preview_view);
SurfaceHolder surfaceHolder = surfaceView.getHolder();
if (hasSurface) {
initCamera(surfaceHolder);
} else {
surfaceHolder.addCallback(this);
surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
decodeFormats =null;
characterSet =null;
playBeep =true;
AudioManager audioService = (AudioManager) getSystemService(AUDIO_SERVICE);
if (audioService.getRingerMode() != AudioManager.RINGER_MODE_NORMAL) {
playBeep =false;
}
initBeepSound();
vibrate =true;
}
initCamera()方法的代码
initCamera
private void initCamera(SurfaceHolder surfaceHolder) {
try {
CameraManager.get().openDriver(surfaceHolder);
} catch (IOException ioe) {
return;
} catch (RuntimeException e) {
return;
}
if (handler ==null) {
handler =new CaptureActivityHandler(this, decodeFormats,
characterSet);
}
}
SurfaceHolder接口实现
@Override
publicvoid surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
}
@Override
publicvoid surfaceCreated(SurfaceHolder holder) {
if (!hasSurface) {
hasSurface =true;
initCamera(holder);
}
}
@Override
publicvoid surfaceDestroyed(SurfaceHolder holder) {
hasSurface =false;
}
initCamera () 方法用于初始化摄像头，如果排除了所有的error ，运行项目时就可以看到大致扫描界面了。 surfaceHolder.addCallback(this);表示让CaptureActivity实现其callback接口。
handler = new CaptureActivityHandler(this, decodeFormats,characterSet) 用于进行扫描解码处理。
解码
上面的步骤主要都是用于对摄像头的控制，而解码的真正工作入口是在CaptureActivityHandler 里面的。新建一个Decoding包把以下文件拷入包中：
- CaptureActivityHandler
- DecodeFormatManager
- DecodeHandler
- DecodeThread
- FinishListener
- InactivityTimer
- Intents
由于我们的包结构和Zxing 项目的有所不同所以需要注意一下类的可访问性
同样开始ctrl+B 编译一下，然后开始修正错误。
在CaptureActivityHandler 里 把 handleMessage 里的部分方法先注释掉如：“decode_succeeded ”分支，这是解码成功时调用 CaptureActivity 展示解码的结果。
在DecodeThread 类里，修改部分涉及Preference配置的代码：
DecodeThread(CaptureActivity activity,
Vector<BarcodeFormat> decodeFormats,
String characterSet,
ResultPointCallback resultPointCallback) {
this.activity = activity;
handlerInitLatch =new CountDownLatch(1);
hints =new Hashtable<DecodeHintType, Object>(3);
//// The prefs can't change while the thread is running, so pick them up once here.
// if (decodeFormats == null || decodeFormats.isEmpty()) {
// SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(activity);
// decodeFormats = new Vector<BarcodeFormat>();
// if (prefs.getBoolean(PreferencesActivity.KEY_DECODE_1D, true)) {
// decodeFormats.addAll(DecodeFormatManager.ONE_D_FORMATS);
// }
// if (prefs.getBoolean(PreferencesActivity.KEY_DECODE_QR, true)) {
// decodeFormats.addAll(DecodeFormatManager.QR_CODE_FORMATS);
// }
// if (prefs.getBoolean(PreferencesActivity.KEY_DECODE_DATA_MATRIX, true)) {
// decodeFormats.addAll(DecodeFormatManager.DATA_MATRIX_FORMATS);
// }
// }
if (decodeFormats ==null|| decodeFormats.isEmpty()) {
decodeFormats =new Vector<BarcodeFormat>();
decodeFormats.addAll(DecodeFormatManager.ONE_D_FORMATS);
decodeFormats.addAll(DecodeFormatManager.QR_CODE_FORMATS);
decodeFormats.addAll(DecodeFormatManager.DATA_MATRIX_FORMATS);
}
hints.put(DecodeHintType.POSSIBLE_FORMATS, decodeFormats);
if (characterSet !=null) {
hints.put(DecodeHintType.CHARACTER_SET, characterSet);
}
hints.put(DecodeHintType.NEED_RESULT_POINT_CALLBACK, resultPointCallback);
}
这里是设置 解码的类型，我们现在默认将所有类型都加入。
返回解码结果
还记得在 CaptureActivityHandler 的 messagehandler 里注销掉的Case分支吗？现在CaptureActivity 里实现它。
错误类型基本上都是：包结构、PreferencesActivity 的配置 、类可访问性的问题。根据错误提示耐心把错误解决。
publicvoid handleDecode(Result obj, Bitmap barcode) {
inactivityTimer.onActivity();
viewfinderView.drawResultBitmap(barcode);
playBeepSoundAndVibrate();
txtResult.setText(obj.getBarcodeFormat().toString() +":"
+ obj.getText());
}
ZXing的简化已基本完成，有几位是可以运行成功的？呵呵。
下面是CaptureActivity的源码:
CaputreActivity
publicclass CaptureActivity extends Activity implements Callback {
private CaptureActivityHandler handler;
private ViewfinderView viewfinderView;
privateboolean hasSurface;
private Vector<BarcodeFormat> decodeFormats;
private String characterSet;
private TextView txtResult;
private InactivityTimer inactivityTimer;
private MediaPlayer mediaPlayer;
privateboolean playBeep;
privatestaticfinalfloat BEEP_VOLUME =0.10f;
privateboolean vibrate;
/** Called when the activity is first created. */
@Override
publicvoid onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
//初始化 CameraManager
CameraManager.init(getApplication());
viewfinderView = (ViewfinderView) findViewById(R.id.viewfinder_view);
txtResult = (TextView) findViewById(R.id.txtResult);
hasSurface =false;
inactivityTimer =new InactivityTimer(this);
}
@Override
protectedvoid onResume() {
super.onResume();
SurfaceView surfaceView = (SurfaceView) findViewById(R.id.preview_view);
SurfaceHolder surfaceHolder = surfaceView.getHolder();
if (hasSurface) {
initCamera(surfaceHolder);
} else {
surfaceHolder.addCallback(this);
surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
decodeFormats =null;
characterSet =null;
playBeep =true;
AudioManager audioService = (AudioManager) getSystemService(AUDIO_SERVICE);
if (audioService.getRingerMode() != AudioManager.RINGER_MODE_NORMAL) {
playBeep =false;
}
initBeepSound();
vibrate =true;
}
@Override
protectedvoid onPause() {
super.onPause();
if (handler !=null) {
handler.quitSynchronously();
handler =null;
}
CameraManager.get().closeDriver();
}
@Override
protectedvoid onDestroy() {
inactivityTimer.shutdown();
super.onDestroy();
}
privatevoid initCamera(SurfaceHolder surfaceHolder) {
try {
CameraManager.get().openDriver(surfaceHolder);
} catch (IOException ioe) {
return;
} catch (RuntimeException e) {
return;
}
if (handler ==null) {
handler =new CaptureActivityHandler(this, decodeFormats,
characterSet);
}
}
@Override
publicvoid surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
}
@Override
publicvoid surfaceCreated(SurfaceHolder holder) {
if (!hasSurface) {
hasSurface =true;
initCamera(holder);
}
}
@Override
publicvoid surfaceDestroyed(SurfaceHolder holder) {
hasSurface =false;
}
public ViewfinderView getViewfinderView() {
return viewfinderView;
}
public Handler getHandler() {
return handler;
}
publicvoid drawViewfinder() {
viewfinderView.drawViewfinder();
}
publicvoid handleDecode(Result obj, Bitmap barcode) {
inactivityTimer.onActivity();
viewfinderView.drawResultBitmap(barcode);
playBeepSoundAndVibrate();
txtResult.setText(obj.getBarcodeFormat().toString() +":"
+ obj.getText());
}
privatevoid initBeepSound() {
if (playBeep && mediaPlayer ==null) {
// The volume on STREAM_SYSTEM is not adjustable, and users found it
// too loud,
// so we now play on the music stream.
setVolumeControlStream(AudioManager.STREAM_MUSIC);
mediaPlayer =new MediaPlayer();
mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
mediaPlayer.setOnCompletionListener(beepListener);
AssetFileDescriptor file = getResources().openRawResourceFd(
R.raw.beep);
try {
mediaPlayer.setDataSource(file.getFileDescriptor(),
file.getStartOffset(), file.getLength());
file.close();
mediaPlayer.setVolume(BEEP_VOLUME, BEEP_VOLUME);
mediaPlayer.prepare();
} catch (IOException e) {
mediaPlayer =null;
}
}
}
privatestaticfinallong VIBRATE_DURATION =200L;
privatevoid playBeepSoundAndVibrate() {
if (playBeep && mediaPlayer !=null) {
mediaPlayer.start();
}
if (vibrate) {
Vibrator vibrator = (Vibrator) getSystemService(VIBRATOR_SERVICE);
vibrator.vibrate(VIBRATE_DURATION);
}
}
/**
* When the beep has finished playing, rewind to queue up another one.
*/
privatefinal OnCompletionListener beepListener =new OnCompletionListener() {
publicvoid onCompletion(MediaPlayer mediaPlayer) {
mediaPlayer.seekTo(0);
}
};
源码下载：http://download.csdn.net/detail/kaka89757/5268842