目前有越來越多的手機(jī)具備自動(dòng)對(duì)焦的拍攝功能，這也意味著這些手機(jī)可以具備條碼掃描的功能。手機(jī)具備條碼掃描的功能，可以優(yōu)化購(gòu)物流程，快速存儲(chǔ)電子名片(二維碼)等。
本文所述實(shí)例就使用了ZXing 1.6實(shí)現(xiàn)條碼/二維碼識(shí)別。ZXing是個(gè)很經(jīng)典的條碼/二維碼識(shí)別的開源類庫，早在很久以前，就有開發(fā)者在J2ME上使用ZXing了，只不過需要支持JSR-234規(guī)范(自動(dòng)對(duì)焦)的手機(jī)才能發(fā)揮其威力，而目前已經(jīng)有不少Android手機(jī)具備自動(dòng)對(duì)焦的功能。
本文代碼運(yùn)行的結(jié)果如下，使用91手機(jī)助手截圖時(shí)，無法截取SurfaceView的實(shí)時(shí)圖像：
本文使用了ZXing1.6的core，即把/zxing-1.6/core/下的src復(fù)制覆蓋工程的src；另外還要使用到/zxing-1.6/android/下的PlanarYUVLuminanceSource.java。
此處需要注意：/zxing-1.6/android/ 是BarcodeScanner的源碼，本文程序相當(dāng)于BarcodeScanner的精簡(jiǎn)版，只保留最基本的識(shí)別功能。
本文完整源碼點(diǎn)擊此處本地下載。
源碼目錄結(jié)果如下圖，ChecksumException.java下面還有很多源文件，截圖尚未列出：
本文例子必須要開攝像頭和自動(dòng)對(duì)焦的權(quán)限，不然啟動(dòng)時(shí)會(huì)報(bào)異常，所用的權(quán)限如下：
<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" />
main.xml源碼如下，main.xml必須要用到FrameLayout才能重疊控件實(shí)現(xiàn)“范圍框”的效果：
<?xml version="1.0" encoding="utf-8"?><FrameLayout android:id="@+id/FrameLayout01" android:layout_width="fill_parent" android:layout_height="fill_parent" xmlns:android="http://schemas.android.com/apk/res/android"> <SurfaceView android:layout_height="fill_parent" android:id="@+id/sfvCamera" android:layout_width="fill_parent"></SurfaceView> <RelativeLayout android:id="@+id/RelativeLayout01" android:layout_height="fill_parent" android:layout_width="fill_parent"> <ImageView android:id="@+id/ImageView01" android:layout_height="100dip" android:layout_width="160dip"></ImageView> <View android:layout_centerVertical="true" android:layout_centerHorizontal="true" android:layout_width="300dip" android:background="#55FF6666" android:id="@+id/centerView" android:layout_height="180dip"></View> <TextView android:layout_centerHorizontal="true" android:layout_width="wrap_content" android:layout_below="@+id/centerView" android:layout_height="wrap_content" android:text="Scanning..." android:id="@+id/txtScanResult" android:textColor="#FF000000"></TextView> </RelativeLayout></FrameLayout>
testCamera.java是主類，負(fù)責(zé)控制Camera和對(duì)圖像做解碼，源碼如下：
package com.testCamera;import java.util.Timer;import java.util.TimerTask;import com.google.zxing.BinaryBitmap;import com.google.zxing.MultiFormatReader;import com.google.zxing.Result;import com.google.zxing.Android.PlanarYUVLuminanceSource;import com.google.zxing.common.HybridBinarizer;import android.app.Activity;import android.graphics.Bitmap;import android.hardware.Camera;import android.os.Bundle;import android.view.SurfaceView;import android.view.View;import android.widget.ImageView;import android.widget.TextView;public class testCamera extends Activity { /** Called when the activity is first created. */ private SurfaceView sfvCamera; private SFHCamera sfhCamera; private ImageView imgView; private View centerView; private TextView txtScanResult; private Timer mTimer; private MyTimerTask mTimerTask; // 按照標(biāo)準(zhǔn)HVGA final static int width = 480; final static int height = 320; int dstLeft, dstTop, dstWidth, dstHeight; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); this.setTitle("Android條碼/二維碼識(shí)別Demo-----hellogv"); imgView = (ImageView) this.findViewById(R.id.ImageView01); centerView = (View) this.findViewById(R.id.centerView); sfvCamera = (SurfaceView) this.findViewById(R.id.sfvCamera); sfhCamera = new SFHCamera(sfvCamera.getHolder(), width, height, previewCallback); txtScanResult=(TextView)this.findViewById(R.id.txtScanResult); // 初始化定時(shí)器 mTimer = new Timer(); mTimerTask = new MyTimerTask(); mTimer.schedule(mTimerTask, 0, 80); } class MyTimerTask extends TimerTask { @Override public void run() { if (dstLeft == 0) {//只賦值一次 dstLeft = centerView.getLeft() * width / getWindowManager().getDefaultDisplay().getWidth(); dstTop = centerView.getTop() * height / getWindowManager().getDefaultDisplay().getHeight(); dstWidth = (centerView.getRight() - centerView.getLeft())* width / getWindowManager().getDefaultDisplay().getWidth(); dstHeight = (centerView.getBottom() - centerView.getTop())* height / getWindowManager().getDefaultDisplay().getHeight(); } sfhCamera.AutoFocusAndPreviewCallback(); } } /** * 自動(dòng)對(duì)焦后輸出圖片 */ private Camera.PreviewCallback previewCallback = new Camera.PreviewCallback() { @Override public void onPreviewFrame(byte[] data, Camera arg1) { //取得指定范圍的幀的數(shù)據(jù) PlanarYUVLuminanceSource source = new PlanarYUVLuminanceSource( data, width, height, dstLeft, dstTop, dstWidth, dstHeight); //取得灰度圖 Bitmap mBitmap = source.renderCroppedGreyscaleBitmap(); //顯示灰度圖 imgView.setImageBitmap(mBitmap); BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source)); MultiFormatReader reader = new MultiFormatReader(); try { Result result = reader.decode(bitmap); String strResult = "BarcodeFormat:" + result.getBarcodeFormat().toString() + " text:" + result.getText(); txtScanResult.setText(strResult); } catch (Exception e) { txtScanResult.setText("Scanning"); } } };}SFHCamera.java是Camera控制類，源碼如下：
package com.testCamera;import java.io.IOException;import android.graphics.PixelFormat;import android.hardware.Camera;import android.util.Log;import android.view.SurfaceHolder;public class SFHCamera implements SurfaceHolder.Callback{ private SurfaceHolder holder = null; private Camera mCamera; private int width,height; private Camera.PreviewCallback previewCallback; public SFHCamera(SurfaceHolder holder,int w,int h,Camera.PreviewCallback previewCallback) { this.holder = holder; this.holder.addCallback(this); this.holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); width=w; height=h; this.previewCallback=previewCallback; } @Override public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) { Camera.Parameters parameters = mCamera.getParameters(); parameters.setPreviewSize(width, height);//設(shè)置尺寸 parameters.setPictureFormat(PixelFormat.JPEG); mCamera.setParameters(parameters); mCamera.startPreview();//開始預(yù)覽 Log.e("Camera","surfaceChanged"); } @Override public void surfaceCreated(SurfaceHolder arg0) { mCamera = Camera.open();//啟動(dòng)服務(wù) try { mCamera.setPreviewDisplay(holder);//設(shè)置預(yù)覽 Log.e("Camera","surfaceCreated"); } catch (IOException e) { mCamera.release();//釋放 mCamera = null; } } @Override public void surfaceDestroyed(SurfaceHolder arg0) { mCamera.setPreviewCallback(null); mCamera.stopPreview();//停止預(yù)覽 mCamera = null; Log.e("Camera","surfaceDestroyed"); } /** * 自動(dòng)對(duì)焦并回調(diào)Camera.PreviewCallback */ public void AutoFocusAndPreviewCallback() { if(mCamera!=null) mCamera.autoFocus(mAutoFocusCallBack); } /** * 自動(dòng)對(duì)焦 */ private Camera.AutoFocusCallback mAutoFocusCallBack = new Camera.AutoFocusCallback() { @Override public void onAutoFocus(boolean success, Camera camera) { if (success) { //對(duì)焦成功，回調(diào)Camera.PreviewCallback mCamera.setOneShotPreviewCallback(previewCallback); } } };}其中testCamera.java的Camera.PreviewCallback previewCallback 是整個(gè)程序的邏輯核心，作為回調(diào)函數(shù)給SFHCamera.java的內(nèi)部Camera類調(diào)用。
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http://tools.VeVB.COm/transcoding/jb51qrcode
希望本文實(shí)例對(duì)大家學(xué)習(xí)Android程序設(shè)計(jì)能有所幫助。
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