标签：android des style blog class code
之前给公司做了一个摄影相关的应用，现在要添加二维码扫描的功能，网上找资料后，虽然已经成功集成到app里面，但是总感觉心里没底儿。所以趁这段时间不是很忙，总结一下。
首先是启动扫描的UI类：
1，Activity启动，当然是onCreate方法
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private CaptureActivityHandler handler;private ViewfinderView viewfinderView;private boolean hasSurface;private Vector<BarcodeFormat> decodeFormats;private String characterSet;private InactivityTimer inactivityTimer;private MediaPlayer mediaPlayer;private boolean playBeep;private static final float BEEP_VOLUME = 0.10f;private
boolean vibrate;/** Called when the activity is first created. */@Overridepublic
void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_capture); // ViewUtil.addTopView(getApplicationContext(), this, // R.string.scan_card); CameraManager.init(getApplication()); viewfinderView = (ViewfinderView) findViewById(R.id.viewfinder_view); Button mButtonBack = (Button) findViewById(R.id.button_back); mButtonBack.setOnClickListener(new
OnClickListener() { @Override public
void onClick(View v) { Scaner.this.finish(); } }); hasSurface = false; inactivityTimer = new
InactivityTimer(this);}@Overrideprotected
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;}@Overrideprotected
void onPause() { super.onPause(); if
(handler != null) { handler.quitSynchronously(); handler = null; } CameraManager.get().closeDriver();}@Overrideprotected
void onDestroy() { inactivityTimer.shutdown(); super.onDestroy();}/** * * * * @param @param result* @param @param barcode* @author Administrator* @return void */public
void handleDecode(Result result, Bitmap barcode) { inactivityTimer.onActivity(); playBeepSoundAndVibrate(); String
resultString = result.getText(); if
(resultString.equals("")) { Toast.makeText(Scaner.this, "Scan failed!",3000).show(); } else
{ //查询keycode 本地数据库 1，优先查询本地库，2，没有本地库，直接跳到知道链接 //分析出keyCode Log.i("testMain","scan_result=====>"+resultString); String
keyCode=""; String[] split1; if(resultString.lastIndexOf("?")<0){ Intent intent = new
Intent(this, InnerBrowser.class); Bundle bundle = new
Bundle(); bundle.putString("result", resultString); //bundle.putParcelable("bitmap", barcode); intent.putExtras(bundle); startActivity(intent);Scaner.this.finish();return; } String[] attr = resultString.substring(resultString.lastIndexOf("?")-1, resultString.length()).split("&"); for
(String string : attr) { split1 = string.split("="); if(split1[0].equalsIgnoreCase("keycode")){ //找到 if(split1.length==2){ keyCode=split1[1]; } } } Log.i("testMain","keyCode=====>"+keyCode); if(!StringUtils.isBlank(keyCode)){ AttractionDAO dao=new
AttractionDAO(Scaner.this); Attraction a=dao.findAttrByKeyCode(keyCode); Log.i("testMain","a=====>"+a); if(a!=null){ Intent it=new
Intent(); it.setClass(Scaner.this, UIAttractionDetail.class); it.putExtra("a", a); startActivity(it); }else{ Intent intent = new
Intent(this, InnerBrowser.class); Bundle bundle = new
Bundle(); bundle.putString("result", resultString); //bundle.putParcelable("bitmap", barcode); intent.putExtras(bundle); startActivity(intent); //this.setResult(RESULT_OK, resultIntent); //使用内置浏览器打开网站内容 } }else{ Intent intent = new
Intent(this, InnerBrowser.class); Bundle bundle = new
Bundle(); bundle.putString("result", resultString); //bundle.putParcelable("bitmap", barcode); intent.putExtras(bundle); startActivity(intent); //this.setResult(RESULT_OK, resultIntent); //使用内置浏览器打开网站内容 } } Scaner.this.finish();}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); }}@Overridepublic
void surfaceChanged(SurfaceHolder holder, int
format, int
width, int
height) {}@Overridepublic
void surfaceCreated(SurfaceHolder holder) { if
(!hasSurface) { hasSurface = true; initCamera(holder); }}@Overridepublic
void surfaceDestroyed(SurfaceHolder holder) { hasSurface = false;}public
ViewfinderView getViewfinderView() { return
viewfinderView;}public
Handler getHandler() { return
handler;}public
void drawViewfinder() { viewfinderView.drawViewfinder();}private
void 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; } }}private
static final long VIBRATE_DURATION = 200L;private
void 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. */private
final OnCompletionListener beepListener = new
OnCompletionListener() { public
void onCompletion(MediaPlayer mediaPlayer) { mediaPlayer.seekTo(0); }}; |
从上面代码可以看出，做了三件事儿：加载布局文件；初始化了一个相机管理器；设置按钮监听，初始化了一个InactivityTimer实例；
然后，最重要的是他实现了一个CallBack函数：具体参见：
此时，
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surfaceCreated |
这个方法会调用然后就初始化相机的一些参数：
前两个我们好理解，第三个是干嘛的？
我们先看布局文件：
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<?xml version="1.0"
encoding="utf-8"?><FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent"
> <RelativeLayout 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_gravity="center"
/> <com.euc.app.scan.view.ViewfinderView android:id="@+id/viewfinder_view" android:layout_width="wrap_content" android:layout_height="wrap_content"
/> <include android:id="@+id/include1" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_alignParentTop="true" layout="@layout/activity_title"
/> </RelativeLayout></FrameLayout> |
可以看到里面有一个自定义的View及surfaceView，
对于我这样的初学者来说，surfaceView 是什么东西？
csdn上看到这个文章
虽然不是很明白，但是大致明白这是个什么东西了。
了解了生命周期之后，我们来看他执行的方法：
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private void initCamera(SurfaceHolder surfaceHolder) { try
{ CameraManager.get().openDriver(surfaceHolder);//配置摄像头 } catch
(IOException ioe) { return; } catch
(RuntimeException e) { return; } if
(handler == null) { handler = new
CaptureActivityHandler(this, decodeFormats, characterSet);//初始化方法里面开启摄像头预览界面。 } } @Override public
void surfaceChanged(SurfaceHolder holder, int
format, int
width, int
height) { } @Override public
void surfaceCreated(SurfaceHolder holder) { if
(!hasSurface) { hasSurface = true; initCamera(holder); } } @Override public
void surfaceDestroyed(SurfaceHolder holder) { hasSurface = false; } |
这个surfaceView 创建出来之后，其实也把摄像头的配置信息以及硬件信息初始化好了。
OK，经过上面一个oncreate以及布局文件的加载，我们已经知道，摄像头预览成功，
这个自定义的View又是干嘛的？我们继续看源码：
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private final int maskColor;private final int resultColor;private final int resultPointColor;private Collection<ResultPoint> possibleResultPoints;private Collection<ResultPoint> lastPossibleResultPoints;boolean isFirst;public ViewfinderView(Context context, AttributeSet attrs) { super(context, attrs); density = context.getResources().getDisplayMetrics().density; //将像素转换成dp ScreenRate = (int)(20
* density); paint = new
Paint(); Resources resources = getResources(); maskColor = resources.getColor(R.color.viewfinder_mask); resultColor = resources.getColor(R.color.result_view); resultPointColor = resources.getColor(R.color.possible_result_points); possibleResultPoints = new
HashSet<ResultPoint>(5);}@Overridepublic
void onDraw(Canvas canvas) { //中间的扫描框，你要修改扫描框的大小，去CameraManager里面修改 Rect frame = CameraManager.get().getFramingRect(); if
(frame == null) { return; } //初始化中间线滑动的最上边和最下边 if(!isFirst){ isFirst = true; slideTop = frame.top; slideBottom = frame.bottom; } //获取屏幕的宽和高 int
width = canvas.getWidth(); int
height = canvas.getHeight(); paint.setColor(resultBitmap != null
? resultColor : maskColor); //画出扫描框外面的阴影部分，共四个部分，扫描框的上面到屏幕上面，扫描框的下面到屏幕下面 //扫描框的左边面到屏幕左边，扫描框的右边到屏幕右边 canvas.drawRect(0, 0, width, frame.top, paint); canvas.drawRect(0, frame.top, frame.left, frame.bottom + 1, paint); canvas.drawRect(frame.right + 1, frame.top, width, frame.bottom + 1, paint); canvas.drawRect(0, frame.bottom + 1, width, height, paint); if
(resultBitmap != null) { // Draw the opaque result bitmap over the scanning rectangle paint.setAlpha(OPAQUE); canvas.drawBitmap(resultBitmap, frame.left, frame.top, paint); } else
{ //画扫描框边上的角，总共8个部分 paint.setColor(Color.GREEN); canvas.drawRect(frame.left, frame.top, frame.left + ScreenRate, frame.top + CORNER_WIDTH, paint); canvas.drawRect(frame.left, frame.top, frame.left + CORNER_WIDTH, frame.top + ScreenRate, paint); canvas.drawRect(frame.right - ScreenRate, frame.top, frame.right, frame.top + CORNER_WIDTH, paint); canvas.drawRect(frame.right - CORNER_WIDTH, frame.top, frame.right, frame.top + ScreenRate, paint); canvas.drawRect(frame.left, frame.bottom - CORNER_WIDTH, frame.left + ScreenRate, frame.bottom, paint); canvas.drawRect(frame.left, frame.bottom - ScreenRate, frame.left + CORNER_WIDTH, frame.bottom, paint); canvas.drawRect(frame.right - ScreenRate, frame.bottom - CORNER_WIDTH, frame.right, frame.bottom, paint); canvas.drawRect(frame.right - CORNER_WIDTH, frame.bottom - ScreenRate, frame.right, frame.bottom, paint); //绘制中间的线,每次刷新界面，中间的线往下移动SPEEN_DISTANCE slideTop += SPEEN_DISTANCE; if(slideTop >= frame.bottom){ slideTop = frame.top; } canvas.drawRect(frame.left + MIDDLE_LINE_PADDING, slideTop - MIDDLE_LINE_WIDTH/2, frame.right - MIDDLE_LINE_PADDING,slideTop + MIDDLE_LINE_WIDTH/2, paint); //画扫描框下面的字 paint.setColor(Color.WHITE); paint.setTextSize(TEXT_SIZE * density); paint.setAlpha(0x40); paint.setTypeface(Typeface.create("System", Typeface.BOLD)); canvas.drawText(getResources().getString(R.string.scan_text), frame.left, (float) (frame.bottom + (float)TEXT_PADDING_TOP *density), paint); Collection<ResultPoint> currentPossible = possibleResultPoints; Collection<ResultPoint> currentLast = lastPossibleResultPoints; if
(currentPossible.isEmpty()) { lastPossibleResultPoints = null; } else
{ possibleResultPoints = new
HashSet<ResultPoint>(5); lastPossibleResultPoints = currentPossible; paint.setAlpha(OPAQUE); paint.setColor(resultPointColor); for
(ResultPoint point : currentPossible) { canvas.drawCircle(frame.left + point.getX(), frame.top + point.getY(), 6.0f, paint); } } if
(currentLast != null) { paint.setAlpha(OPAQUE / 2); paint.setColor(resultPointColor); for
(ResultPoint point : currentLast) { canvas.drawCircle(frame.left + point.getX(), frame.top + point.getY(), 3.0f, paint); } } //只刷新扫描框的内容，其他地方不刷新 postInvalidateDelayed(ANIMATION_DELAY, frame.left, frame.top, frame.right, frame.bottom); }}public
void drawViewfinder() { resultBitmap = null; invalidate();}/** * Draw a bitmap with the result points highlighted instead of the live * scanning display. * * @param barcode * An image of the decoded barcode. */public
void drawResultBitmap(Bitmap barcode) { resultBitmap = barcode; invalidate();}public
void addPossibleResultPoint(ResultPoint point) { possibleResultPoints.add(point);} |
哦，这个就是定义了一个有动态效果的扫描界面
上面的虽然代码不多，当时我们现在回忆一下步骤：
1，启动activity，加载布局文件，初始化surfaceView,初始化自定义的View（动态界面），
2，在初始化surfaceView的时候，同时初始化了摄像头的参数，初始化的handler处理器，启动了摄像头预览。
问题：那什么时候开始监听扫描二维码的呢？
初始化handler 的时候就开始监听了，看一下其构造函数：
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public CaptureActivityHandler(Scaner activity, Vector<BarcodeFormat> decodeFormats, String
characterSet) { this.activity = activity; decodeThread = new
DecodeThread(activity, decodeFormats, characterSet, new
ViewfinderResultPointCallback(activity.getViewfinderView())); decodeThread.start(); state = State.SUCCESS; // Start ourselves capturing previews and decoding. CameraManager.get().startPreview(); restartPreviewAndDecode(); } |
再来一个：上面构造函数new了一个对象，这个对象就是用来监听获取扫描的图像的。
直到获取了二维码图像，调用回调函数就结束。
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final class DecodeThread extends
Thread { public
static final String BARCODE_BITMAP = "barcode_bitmap"; private
final Scaner activity; private
final Hashtable<DecodeHintType, Object> hints; private
Handler handler; private
final CountDownLatch handlerInitLatch; DecodeThread(Scaner activity, Vector<BarcodeFormat> decodeFormats, String
characterSet, ResultPointCallback resultPointCallback) { this.activity = activity; handlerInitLatch = new
CountDownLatch(1); hints = new
Hashtable<DecodeHintType, Object>(3); 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); } Handler getHandler() { try
{ handlerInitLatch.await(); } catch
(InterruptedException ie) { // continue? } return
handler; } @Override public
void run() { Looper.prepare(); handler = new
DecodeHandler(activity, hints); handlerInitLatch.countDown(); Looper.loop(); }} |
回调函数：
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public void handleDecode(Result result, Bitmap barcode) { inactivityTimer.onActivity(); playBeepSoundAndVibrate(); String
resultString = result.getText(); if
(resultString.equals("")) { Toast.makeText(Scaner.this, "Scan failed!",3000).show(); } else
{ //扫描结果的处理。 } Scaner.this.finish();} |
android 利用ZXING扫描二维码代码分析,布布扣,bubuko.com
标签：android des style blog class code
原文地址：http://www.cnblogs.com/tony-jingzhou/p/3716530.html
