Android 二维码扫描怎样实现第二次（重复）扫描

相关文章：

Android 基于google Zxing实现二维码、条形码扫描，仿微信二维码扫描效果

http://blog.csdn.net/xiaanming/article/details/10163203

下载地址：http://download.csdn.net/detail/xiaanming/5990219

首先看一下扫描界面

CaptureCodeActivity.java代码：

package com.haier.qr.code;

import java.io.IOException;
import java.io.Serializable;
import java.util.Map;
import java.util.Vector;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.DialogInterface.OnCancelListener;
import android.content.DialogInterface.OnClickListener;
import android.content.Intent;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.os.Handler;
import android.text.TextUtils;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceHolder.Callback;
import android.view.SurfaceView;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.widget.Toast;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.DecodeHintType;
import com.google.zxing.Result;
import com.haier.cabinet.customer.R;
import com.haier.cabinet.customer.activity.DeliveryBoxListActivity;
import com.haier.common.util.AppToast;
import com.haier.qr.code.zxing.camera.CameraManager;
import com.haier.qr.code.zxing.decoding.CaptureActivityHandler;
import com.haier.qr.code.zxing.decoding.FinishListener;
import com.haier.qr.code.zxing.decoding.InactivityTimer;
import com.haier.qr.code.zxing.view.ViewfinderView;

/**
 * Initial the camera
 * 
 * @author jdsjlzx
 */
public class CaptureCodeActivity extends Activity implements Callback,View.OnClickListener {

	private static final String TAG = CaptureCodeActivity.class
			.getSimpleName();

	private CameraManager cameraManager;
	private CaptureActivityHandler handler;
	private ViewfinderView viewfinderView;
	private boolean hasSurface;
	private Map<DecodeHintType, ?> decodeHints;
	private Vector<BarcodeFormat> decodeFormats;
	private String characterSet;
	private InactivityTimer inactivityTimer;
	private boolean isFlashlightOpen;
	/**
	 * 声音震动管理器。如果扫描成功后可以播放一段音频，也可以震动提醒，可以通过配置来决定扫描成功后的行为。
	 */
	private BeepManager beepManager;

	/**
	 * 闪光灯调节器。自动检测环境光线强弱并决定是否开启闪光灯
	 */
	private AmbientLightManager ambientLightManager;

	public CameraManager getCameraManager() {
		return cameraManager;
	}

	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		Window window = getWindow();
		window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
		setContentView(R.layout.activity_capture);

		hasSurface = false;
		inactivityTimer = new InactivityTimer(this);

		beepManager = new BeepManager(this);
		ambientLightManager = new AmbientLightManager(this);
		
		//按钮监听事件
		findViewById(R.id.capture_flashlight).setOnClickListener(this);
	}

	@Override
	protected void onResume() {
		super.onResume();
		Log.d(TAG, "onResume");
		cameraManager = new CameraManager(getApplication());
		viewfinderView = (ViewfinderView) findViewById(R.id.viewfinder_view);
		viewfinderView.setCameraManager(cameraManager);
		viewfinderView.setVisibility(View.VISIBLE);

		SurfaceView surfaceView = (SurfaceView) findViewById(R.id.preview_view);
		SurfaceHolder surfaceHolder = surfaceView.getHolder();
		if (hasSurface) {
			initCamera(surfaceHolder);
		} else {
			// 防止sdk8的设备初始化预览异常
			surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

			// Install the callback and wait for surfaceCreated() to init the
			// camera.
			surfaceHolder.addCallback(this);
		}
		decodeFormats = null;
		characterSet = null;

		// 加载声音配置，其实在BeemManager的构造器中也会调用该方法，即在onCreate的时候会调用一次
		beepManager.updatePrefs();

		// 启动闪光灯调节器
		ambientLightManager.start(cameraManager);

		// 恢复活动监控器
		inactivityTimer.onResume();


	}

	
	@Override
	protected void onPause() {
		Log.d(TAG, "onPause");
		if (handler != null) {
			handler.quitSynchronously();
			handler = null;
		}
		inactivityTimer.onPause();
		ambientLightManager.stop();
		beepManager.close();

		// 关闭摄像头
		cameraManager.closeDriver();
		if (!hasSurface) {
			SurfaceView surfaceView = (SurfaceView) findViewById(R.id.preview_view);
			SurfaceHolder surfaceHolder = surfaceView.getHolder();
			surfaceHolder.removeCallback(this);
		}
		super.onPause();
	}

	@Override
	protected void onDestroy() {
		inactivityTimer.shutdown();
		super.onDestroy();
	}

	/**
	 * A valid barcode has been found, so give an indication of success and show
	 * the results.
	 * 
	 * @param rawResult
	 *            The contents of the barcode.
	 * @param scaleFactor
	 *            amount by which thumbnail was scaled
	 * @param barcode
	 *            A greyscale bitmap of the camera data which was decoded.
	 */
	public void handleDecode(Result rawResult, Bitmap barcode, float scaleFactor) {
		Log.d(TAG, "handleDecode");
		inactivityTimer.onActivity();
		
		beepManager.playBeepSoundAndVibrate();
		
		String resultString = rawResult.getText();
		if (TextUtils.isEmpty(resultString)) {
			Toast.makeText(CaptureCodeActivity.this, "Scan failed!",
					Toast.LENGTH_SHORT).show();
		} else {
			//扫码完成，处理结果（跳转到箱子列表）
			/*Intent resultIntent = new Intent();
			Bundle bundle = new Bundle();
			bundle.putString("result", resultString);
			bundle.putParcelable("bitmap", barcode);
			resultIntent.putExtras(bundle);
			this.setResult(RESULT_OK, resultIntent);*/
			String terminalNo = getIntent().getStringExtra("terminal_no");
			if (resultString.equals(terminalNo)) {
				AppToast.makeToast(this, "确认成功！");
				Intent intent = new Intent(this, DeliveryBoxListActivity.class);
				intent.putExtra("terminal_no", terminalNo);
				intent.putExtra("box_list", (Serializable) getIntent().getSerializableExtra("box_list"));
				startActivity(intent);
				CaptureCodeActivity.this.finish();
			} else {
				/*AppToast.makeToast(this, "确认失败，请重新扫描确认");*/
				showErrorDialog();
			}
			
		}
		
	}

	private void initCamera(SurfaceHolder surfaceHolder) {
		if (surfaceHolder == null) {
			throw new IllegalStateException("No SurfaceHolder provided");
		}
		if (cameraManager.isOpen()) {
			Log.w(TAG,
					"initCamera() while already open -- late SurfaceView callback?");
			return;
		}
		try {
			cameraManager.openDriver(surfaceHolder);
			// Creating the handler starts the preview, which can also throw a
			// RuntimeException.
			if (handler == null) {
				handler = new CaptureActivityHandler(this, decodeFormats,
						decodeHints, characterSet, cameraManager);
			}

		} catch (IOException ioe) {
			Log.w(TAG, ioe);
			displayFrameworkBugMessageAndExit();
		} catch (RuntimeException e) {
			// Barcode Scanner has seen crashes in the wild of this variety:
			// java.?lang.?RuntimeException: Fail to connect to camera service
			Log.w(TAG, "Unexpected error initializing camera", e);
			displayFrameworkBugMessageAndExit();
		}
	}

	private void displayFrameworkBugMessageAndExit() {
		AlertDialog.Builder builder = new AlertDialog.Builder(this);
		builder.setTitle(getString(R.string.app_name));
		builder.setMessage(getString(R.string.msg_camera_framework_bug));
		builder.setPositiveButton(android.R.string.yes, new FinishListener(this));
		builder.setOnCancelListener(new FinishListener(this));
		builder.show();
	}

	@Override
	public void surfaceChanged(SurfaceHolder holder, int format, int width,
			int height) {

	}

	@Override
	public void surfaceCreated(SurfaceHolder holder) {
		if (holder == null) {
			Log.e(TAG,
					"*** WARNING *** surfaceCreated() gave us a null surface!");
		}
		if (!hasSurface) {
			hasSurface = true;
			initCamera(holder);
		}

	}

	@Override
	public void surfaceDestroyed(SurfaceHolder holder) {
		hasSurface = false;

	}

	public ViewfinderView getViewfinderView() {
		return viewfinderView;
	}

	public Handler getHandler() {
		return handler;
	}

	public void drawViewfinder() {
		viewfinderView.drawViewfinder();

	}

	@Override
	public void onClick(View v) {
		switch (v.getId()) {

		case R.id.capture_flashlight:
			if (isFlashlightOpen) {
				cameraManager.setTorch(false); // 关闭闪光灯
				isFlashlightOpen = false;
			}
			else {
				cameraManager.setTorch(true); // 打开闪光灯
				isFlashlightOpen = true;
			}
			break;
		default:
			break;
	}
	}

	private void showErrorDialog() {
		closeCamera();
		viewfinderView.setVisibility(View.GONE);
		AlertDialog.Builder builder = new AlertDialog.Builder(this);
		builder.setTitle(getString(R.string.app_name));
		builder.setMessage("扫描确认出错，请重新扫描二维码！");
		builder.setPositiveButton(android.R.string.ok, new OnClickListener() {
			
			@Override
			public void onClick(DialogInterface dialog, int which) {
				restartCamera();
			}
		});
		builder.setOnCancelListener(new OnCancelListener() {
			
			@Override
			public void onCancel(DialogInterface dialog) {
				CaptureCodeActivity.this.finish();
			}
		});
		builder.show();
	}
	
	void restartCamera(){
		Log.d(TAG, "hasSurface " + hasSurface);

		viewfinderView.setVisibility(View.VISIBLE);

		SurfaceView surfaceView = (SurfaceView) findViewById(R.id.preview_view);
		SurfaceHolder surfaceHolder = surfaceView.getHolder();
		initCamera(surfaceHolder);
			
		// 恢复活动监控器
		inactivityTimer.onResume();
	}
	
	void closeCamera(){
		if (handler != null) {
			handler.quitSynchronously();
			handler = null;
		}
		inactivityTimer.onPause();

		// 关闭摄像头
		cameraManager.closeDriver();
	}

}

private void showErrorDialog() {
		closeCamera();
		viewfinderView.setVisibility(View.GONE);
		AlertDialog.Builder builder = new AlertDialog.Builder(this);
		builder.setTitle(getString(R.string.app_name));
		builder.setMessage("扫描确认出错，请重新扫描柜子上的二维码！");
		builder.setPositiveButton(android.R.string.ok, new OnClickListener() {
			
			@Override
			public void onClick(DialogInterface dialog, int which) {
				restartCamera();
			}
		});
		builder.setOnCancelListener(new OnCancelListener() {
			
			@Override
			public void onCancel(DialogInterface dialog) {
				CaptureCodeActivity.this.finish();
			}
		});
		builder.show();
	}

closeCamera（相当于onPause）和restartCamera（onResume）方法就不贴代码了。

Demo还有个问题，就是在低分辨率上面扫描区域出现了变形，我已经修改了，改天把代码打包发出来！可以加我QQ通知我！

先把代码贴出来：

ViewfinderView.java

/*
 * Copyright (C) 2008 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.haier.qr.code.zxing.view;

import java.util.Collection;
import java.util.HashSet;

import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.View;

import com.google.zxing.ResultPoint;
import com.haier.cabinet.postman.R;
import com.haier.qr.code.zxing.camera.CameraManager;

/**
 * This view is overlaid on top of the camera preview. It adds the viewfinder
 * rectangle and partial transparency outside it, as well as the laser scanner
 * animation and result points.
 * 
 */
public final class ViewfinderView extends View {
	private static final String TAG = "ViewfinderView";
	/**
	 * 刷新界面的时间
	 */
	private static final long ANIMATION_DELAY = 10L;
	private static final int OPAQUE = 0xFF;

	/**
	 * 四个绿色边角对应的长度
	 */
	private int ScreenRate;
	
	/**
	 * 四个绿色边角对应的宽度
	 */
	private static final int CORNER_WIDTH = 10;
	/**
	 * 扫描框中的中间线的宽度
	 */
	private static final int MIDDLE_LINE_WIDTH = 6;
	
	/**
	 * 扫描框中的中间线的与扫描框左右的间隙
	 */
	private static final int MIDDLE_LINE_PADDING = 5;
	
	/**
	 * 中间那条线每次刷新移动的距离
	 */
	private static final int SPEEN_DISTANCE = 5;
	
	/**
	 * 手机的屏幕密度
	 */
	private static float density;
	/**
	 * 字体大小
	 */
	private static final int TEXT_SIZE = 16;
	/**
	 * 字体距离扫描框下面的距离
	 */
	private static final int TEXT_PADDING_TOP = 30;
	
	/**
	 * 画笔对象的引用
	 */
	private Paint paint;
	
	/**
	 * 中间滑动线的最顶端位置
	 */
	private int slideTop;
	
	/**
	 * 中间滑动线的最底端位置
	 */
	private int slideBottom;
	
	/**
	 * 将扫描的二维码拍下来，这里没有这个功能，暂时不考虑
	 */
	private Bitmap resultBitmap;
	private final int maskColor;
	private final int resultColor;
	
	private final int resultPointColor;
	private Collection<ResultPoint> possibleResultPoints;
	private Collection<ResultPoint> lastPossibleResultPoints;

	boolean isFirst;
	private CameraManager cameraManager;
	
	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);
	}

	public void setCameraManager(CameraManager cameraManager) {
		this.cameraManager = cameraManager;
	}
	
	@Override
	public void onDraw(Canvas canvas) {
		if (cameraManager == null) {
			return; // not ready yet, early draw before done configuring
		}
		//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.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);*/
			
			
<span style="white-space:pre">			</span>
			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);
	}

}

更多详见：https://github.com/jdsjlzx/Customer/tree/master/android_app/src/main/java/com/haier/qr/code