Question

在我的Android应用程序中，我使用了一个使用BarcodeView的片段（CameraFragment见下文）。当扫描条形码（BarcodeCallBack）时，我检查它是否适合模式，如果不是，我想恢复扫描，但这不起作用。相机保持运行但没有扫描条形码。作为一个quickfix我替换整个片段，但这不是它必须如何......

碎片：

package com.stickydata;
import android.Manifest;
import android.content.Context;
import android.content.pm.PackageManager;
import android.os.Build;
import android.os.Bundle;
import android.os.Vibrator;
import android.support.annotation.NonNull;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.amazonaws.mobile.AWSMobileClient;
import com.amazonaws.mobilehelper.auth.IdentityManager;
import com.google.zxing.ResultPoint;
import com.journeyapps.barcodescanner.BarcodeCallback;
import com.journeyapps.barcodescanner.BarcodeResult;
import com.journeyapps.barcodescanner.BarcodeView;
import com.stickydata.AWSUtil.SDtagUtil;
import com.stickydata.events.EventResumeBarcodeScan;

import org.greenrobot.eventbus.EventBus;

import java.util.List;

import static com.facebook.FacebookSdk.getApplicationContext;

public class CameraFragment extends Fragment  {
    private IdentityManager identityManager;
Context mcontext;
    private BarcodeView barcodeView;
    final int PERMISSIONS_REQUEST_ACCESS_CAMERA=0;
    View view;


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        view=inflater.inflate(R.layout.fragment_camera, container, false);

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M &&
                getActivity().checkSelfPermission(Manifest.permission.CAMERA)
                        != PackageManager.PERMISSION_GRANTED) {
            requestPermissions(new String[]{Manifest.permission.CAMERA},
                    PERMISSIONS_REQUEST_ACCESS_CAMERA);
        } else {
            barcodeView = (BarcodeView) view.findViewById(R.id.barcode_scanner);
            barcodeView.decodeSingle(callback);

        }


        mcontext=getContext();

        return view;
    }



    @Override
    public void onResume() {

        super.onResume();
        barcodeView = (BarcodeView) view.findViewById(R.id.barcode_scanner);
        barcodeView.resume();
        barcodeView.decodeSingle(callback);

    }

    @Override
    public void onPause() {
        super.onPause();
        barcodeView = (BarcodeView) view.findViewById(R.id.barcode_scanner);
        barcodeView.pause();
    }


    private BarcodeCallback callback = new BarcodeCallback() {
        @Override
        public void barcodeResult(BarcodeResult result) {
            if (result.getText() != null) {
                barcodeView.pause();
                //the vibrator on success
                Vibrator v = (Vibrator) getApplicationContext().getSystemService(Context.VIBRATOR_SERVICE);
               // Vibrate for 500 milliseconds
                v.vibrate(200);
               //after the string has been read we prozess it
                String tag_string=result.getText();
                AWSMobileClient.initializeMobileClientIfNecessary(getApplicationContext());
                // Obtain a reference to the mobile client. It is created in the Application class.
                final AWSMobileClient awsMobileClient = AWSMobileClient.defaultMobileClient();

                // Obtain a reference to the identity manager.
                identityManager = awsMobileClient.getIdentityManager();
                SDtagUtil sdTag=new SDtagUtil(tag_string,identityManager,awsMobileClient,mcontext);

                if(!sdTag.prozessTag()){//if the tag was not scanned succesfully let us start the scan again
                    EventBus.getDefault().post(new EventResumeBarcodeScan("bla"));
                    //TODO NOT WORKING
                  //  barcodeView.resume();
                  //  barcodeView.decodeSingle(callback);

                }


            }


        }

        @Override
        public void possibleResultPoints(List<ResultPoint> resultPoints) {
        }
    };

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);

        if (requestCode == PERMISSIONS_REQUEST_ACCESS_CAMERA|| grantResults!=null) {
            if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                barcodeView = (BarcodeView) view.findViewById(R.id.barcode_scanner);
                barcodeView.decodeContinuous(callback);
            }
        }
    }
}

片段xml文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">


    <com.journeyapps.barcodescanner.BarcodeView
        android:id="@+id/barcode_scanner"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:zxing_use_texture_view="true"
    app:zxing_preview_scaling_strategy="fitCenter"/>
</LinearLayout>

按建议更改为decodeContinous。问题仍然存在：

package com.stickydata;
import android.Manifest;
import android.content.Context;
import android.content.pm.PackageManager;
import android.os.Build;
import android.os.Bundle;
import android.os.Vibrator;
import android.support.annotation.NonNull;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.amazonaws.mobile.AWSMobileClient;
import com.amazonaws.mobilehelper.auth.IdentityManager;
import com.google.zxing.ResultPoint;
import com.journeyapps.barcodescanner.BarcodeCallback;
import com.journeyapps.barcodescanner.BarcodeResult;
import com.journeyapps.barcodescanner.BarcodeView;
import com.stickydata.AWSUtil.SDtagUtil;
import com.stickydata.events.EventResumeBarcodeScan;

import org.greenrobot.eventbus.EventBus;

import java.util.List;

import static com.facebook.FacebookSdk.getApplicationContext;

public class CameraFragment extends Fragment  {
    private IdentityManager identityManager;
Context mcontext;
    private BarcodeView barcodeView;
    final int PERMISSIONS_REQUEST_ACCESS_CAMERA=0;
    View view;


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        view=inflater.inflate(R.layout.fragment_camera, container, false);

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M &&
                getActivity().checkSelfPermission(Manifest.permission.CAMERA)
                        != PackageManager.PERMISSION_GRANTED) {
            requestPermissions(new String[]{Manifest.permission.CAMERA},
                    PERMISSIONS_REQUEST_ACCESS_CAMERA);
        } else {
            barcodeView = (BarcodeView) view.findViewById(R.id.barcode_scanner);
            barcodeView.decodeContinuous(callback);

        }


        mcontext=getContext();

        return view;
    }



    @Override
    public void onResume() {

        super.onResume();
        barcodeView = (BarcodeView) view.findViewById(R.id.barcode_scanner);
        barcodeView.resume();
        barcodeView.decodeContinuous(callback);

    }

    @Override
    public void onPause() {
        super.onPause();
        barcodeView = (BarcodeView) view.findViewById(R.id.barcode_scanner);
        barcodeView.pause();
    }


    private BarcodeCallback callback = new BarcodeCallback() {
        @Override
        public void barcodeResult(BarcodeResult result) {
            if (result.getText() != null) {
                barcodeView.pause();
                //the vibrator on success
                Vibrator v = (Vibrator) getApplicationContext().getSystemService(Context.VIBRATOR_SERVICE);
               // Vibrate for 500 milliseconds
                v.vibrate(200);
               //after the string has been read we prozess it
                String tag_string=result.getText();
                AWSMobileClient.initializeMobileClientIfNecessary(getApplicationContext());
                // Obtain a reference to the mobile client. It is created in the Application class.
                final AWSMobileClient awsMobileClient = AWSMobileClient.defaultMobileClient();

                // Obtain a reference to the identity manager.
                identityManager = awsMobileClient.getIdentityManager();
                SDtagUtil sdTag=new SDtagUtil(tag_string,identityManager,awsMobileClient,mcontext);

                if(!sdTag.prozessTag()){//if the tag was not scanned succesfully let us start the scan again
                   // EventBus.getDefault().post(new EventResumeBarcodeScan("bla"));
                    //TODO NOT WORKING
                    barcodeView.resume();
                    barcodeView.decodeContinuous(callback);

                }


            }


        }

        @Override
        public void possibleResultPoints(List<ResultPoint> resultPoints) {
        }
    };

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);

        if (requestCode == PERMISSIONS_REQUEST_ACCESS_CAMERA|| grantResults!=null) {
            if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                barcodeView = (BarcodeView) view.findViewById(R.id.barcode_scanner);
                barcodeView.decodeContinuous(callback);
            }
        }
    }
}

Answer 1

您好user1406731使用了错误的回调，我们在移动应用中做了类似的事情。用decodeContinuous（）回调替换你的decodeSingle（）回调函数，它应该工作。以下是官方文档Continous Callback example中的一个工作示例。希望它可以帮到你。

您好，我试图运行您的代码＆amp;做了一点改变。这是我测试过的，对我来说很好用

import android.Manifest;
import android.content.Context;
import android.content.pm.PackageManager;
import android.os.Build;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.google.zxing.ResultPoint;
import com.journeyapps.barcodescanner.BarcodeCallback;
import com.journeyapps.barcodescanner.BarcodeResult;
import com.journeyapps.barcodescanner.BarcodeView;
import com.example.scanner.R;
import com.example.scanner.ui.base.BaseFragment;

import java.util.List;

/**
 * Created by Rishabh Bhatia on 12/5/17.
 */

public class CameraFragment extends BaseFragment {
    Context mcontext;
    private BarcodeView barcodeView;
    final int PERMISSIONS_REQUEST_ACCESS_CAMERA=0;
    View view;


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        view=inflater.inflate(R.layout.fragment_camera, container, false);

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M &&
                getActivity().checkSelfPermission(Manifest.permission.CAMERA)
                        != PackageManager.PERMISSION_GRANTED) {
            requestPermissions(new String[]{Manifest.permission.CAMERA},
                    PERMISSIONS_REQUEST_ACCESS_CAMERA);
        } else {
            barcodeView = (BarcodeView) view.findViewById(R.id.barcode_scanner);
            barcodeView.decodeContinuous(callback);

        }


        mcontext=getContext();

        return view;
    }



    @Override
    public void onResume() {

        super.onResume();
        barcodeView = (BarcodeView) view.findViewById(R.id.barcode_scanner);
        barcodeView.resume();    
    }

    @Override
    public void onPause() {
        super.onPause();
        barcodeView = (BarcodeView) view.findViewById(R.id.barcode_scanner);
        barcodeView.pause();
    }

    private BarcodeCallback callback = new BarcodeCallback() {
        @Override
        public void barcodeResult(BarcodeResult result) {
            if (result.getText() != null) {
                barcodeView.pause();
                //after the string has been read we prozess it
                String tag_string=result.getText();
                Log.e("RISHABH", "pausing scanner, got some data "+tag_string);

                if(!tag_string.equals("abc")){//if the tag was not scanned succesfully let us start the scan again
                    Log.e("RISHABH", "resuming scanner, data needed was not found");
                    barcodeView.resume(); //notice we don't call decodeContinuous function again
                }
            }
        }

        @Override
        public void possibleResultPoints(List<ResultPoint> resultPoints) {
        }
    };

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);

        if (requestCode == PERMISSIONS_REQUEST_ACCESS_CAMERA) {
            if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                barcodeView = (BarcodeView) view.findViewById(R.id.barcode_scanner);
                barcodeView.decodeContinuous(callback);
            }
        }
    }
}

这是我的logcat

05-12 23:54:13.226 31403-31403/com.example.scanner E/RISHABH: pausing scanner, got some data ABC-abc-1234
05-12 23:54:13.226 31403-31403/com.example.scanner E/RISHABH: resuming scanner, data needed was not found
05-12 23:54:18.280 31403-31403/com.example.scanner E/RISHABH: pausing scanner, got some data ABC-abc-1234
05-12 23:54:18.280 31403-31403/com.example.scanner E/RISHABH: resuming scanner, data needed was not found
05-12 23:54:19.350 31403-31403/com.example.scanner E/RISHABH: pausing scanner, got some data ABC-abc-1234
05-12 23:54:19.350 31403-31403/com.example.scanner E/RISHABH: resuming scanner, data needed was not found
05-12 23:54:20.350 31403-31403/com.example.scanner E/RISHABH: pausing scanner, got some data ABC-abc-1234
05-12 23:54:20.350 31403-31403/com.example.scanner E/RISHABH: resuming scanner, data needed was not found
05-12 23:54:21.450 31403-31403/com.example.scanner E/RISHABH: pausing scanner, got some data ABC-abc-1234
05-12 23:54:21.450 31403-31403/com.example.scanner E/RISHABH: resuming scanner, data needed was not found
05-12 23:54:22.510 31403-31403/com.example.scanner E/RISHABH: pausing scanner, got some data ABC-abc-1234
05-12 23:54:22.510 31403-31403/com.example.scanner E/RISHABH: resuming scanner, data needed was not found
05-12 23:54:33.000 31403-31403/com.example.scanner E/RISHABH: pausing scanner, got some data abc

Answer 2

我想出了办法，并认为这可能对某人有所帮助。我遇到了完全相同的问题，然后弄清楚resume（）方法会检查它是否在MainThread上运行。

public class Util {
    public static void validateMainThread() {
        if (Looper.getMainLooper() != Looper.myLooper()) {
            throw new IllegalStateException("Must be called from the main thread.");
        }
    }
}

以下是如何在MainThread上运行代码的示例： Running code in main thread from another thread

我试图从@JavscriptInterface方法运行它，这是我的代码：

public class MyInterface {
    Context mContext;
    ActivityMain activityMain;

    MyInterface(Context c, ActivityMain am) {
        mContext = c;
        activityMain = am;
    }

    @JavascriptInterface
    public void resumeScanner() {
        Toast.makeText(mContext, "resume", Toast.LENGTH_SHORT).show();
        Handler mainHandler = new Handler(mContext.getMainLooper());
        Runnable myRunnable = new Runnable() {
            @Override
            public void run() {
                activityMain.barcodeView.resume();
            }
        };
        mainHandler.post(myRunnable);
    }
}

Android zxing嵌入式BarcodeView无法恢复

2 个答案: