在ZXingScannerView中恢复片段后扫描仪不显示

Question

我在片段中使用扫描仪。在第一次尝试扫描仪工作正常，但是当我移动到新的活动并返回时，扫描仪不显示。

public class SampleFragment extends Fragment implements ZXingScannerView.ResultHandler{ 

    private ZXingScannerView mScannerView; 
    private LinearLayout qrCameraLayout; 

    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
     View fragmentView = inflater.inflate(R.layout.fragment_qr_code_reader, container, false); 
     qrCameraLayout = (LinearLayout) fragmentView.findViewById(R.id.ll_qrcamera); 
     mScannerView = new ZXingScannerView(getActivity()); 
     mScannerView.setLayoutParams(new LinearLayout.LayoutParams(
       LinearLayout.LayoutParams.MATCH_PARENT, 
       LinearLayout.LayoutParams.MATCH_PARENT)); 
     mScannerView.setResultHandler(this); 
     mScannerView.startCamera(); 
     qrCameraLayout.addView(mScannerView); 
     return fragmentView; 
    } 
    @Override 
    public void onResume`enter code here`() 
    { 
     super.onResume(); 
     if(mScannerView==null) 
     mScannerView.resumeCameraPreview(this); 
     //after I switch to new activity and reopen, then scanner is not shown 
    } 
    @Override 
    public void onPause() 
    { 
     super.onPause(); 
     mScannerView.resumeCameraPreview(this); 
     mScannerView=null; 
    } 



    @Override 
    public void handleResult(Result result) { 

     Toast.makeText(getActivity(),result.getText().toString(),Toast.LENGTH_LONG).show(); 

    } 
} 

Answer 1

试图改变的onResume和方法的onPause这个

@Override 
public void onResume() { 
    super.onResume(); 
    mScannerView.setResultHandler(this); // Register ourselves as a handler for scan results. 
    mScannerView.startCamera();   // Start camera on resume 
} 

@Override 
public void onPause() { 
    super.onPause(); 
    mScannerView.stopCamera();   // Stop camera on pause 
}