Android zxing：相机显示黑屏或第二次调用Scanner片段时死机

Question

I have a "Scan Fragment" & "Product Form fragment". Task flow goes like, Main Activity -> ScanFragment (button click / scan something ) --> Form fragment (button click) --> ScanFragment (show same fragment again)

It works well if ScanFragment is to be shown only one time. But, when called for second time, Scan fragment shows black screen. If stopped camera when moving to product Fragment from ScanFragment then, it freezes. I think its camera problem, but couldn't figure out how to solve this.

ScanFragment onClick method:

private void onClickMethods(){
     btn_Skip.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            PrintLog.show("-- Skip Button is clicked ---");
            //releaseCamera(); -- if used, then shows camera but camera freezes
            ProductDetailFormFragment productDetailFormFragment  = new ProductDetailFormFragment();
            getActivity().getSupportFragmentManager().beginTransaction()
                    .add(R.id.mainFragment, productDetailFormFragment).addToBackStack(AppConstants.C_BACKSTACK_SCAN).commit();

    });
}

private void releaseCamera(){
// calls child fragment's camera releasing methods here
// if used camera shows freezed screen only
    SimpleScannerFragment simpleScannerFragment = (SimpleScannerFragment) getChildFragmentManager()
            .findFragmentById(R.id.scanner_fragment);
    simpleScannerFragment.releaseCamera();
}

SimpleScannerFragment (containing zxing code) is included in Scanlayout as follows :

<LinearLayout...... >
 .....
<fragment android:name="np.com.lins.serviceapp.UI.Modules.BarcodeScanner.SimpleScannerFragment"
    android:id="@+id/scanner_fragment"
    android:layout_weight="1"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />
....
</LinearLayout>

SimpleScannerFragment code :

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    mScannerView = new ZXingScannerView(getActivity());
    PrintLog.show("===  Scanner Fragment : before Return view ==");
    return mScannerView;
}

@Override
public void onResume() {
    super.onResume();
    PrintLog.show("Resume state===");
    mScannerView.setResultHandler(this);
    mScannerView.stopCamera();
    mScannerView.startCamera();
}

//called by parent ScanFragment
public void releaseCamera(){
    try{
        mScannerView.stopCameraPreview();
        mScannerView.stopCamera();
    }catch (Exception e){
        PrintLog.showException(TAG,"== exception while releasing camera resourc == ",e);
    }
}

@Override
public void onPause() {
    super.onPause();
    mScannerView.stopCameraPreview();
    mScannerView.stopCamera();
}

ProductDetailFormFragment code :

    public void scanFromFragment() {
    ScanFragment scanFragment = new ScanFragment();
    Bundle bundle = new Bundle();
    bundle.putString(AppConstants.C_PARENT_FRAGMENT,AppConstants.C_FRAGMENT_PRODUCT_DETAILS);
    scanFragment.setArguments(bundle);
    getActivity().getSupportFragmentManager().beginTransaction()
            .add(R.id.mainFragment, scanFragment).addToBackStack(AppConstants.C_BACKSTACK_PRODUCT_DETAIL_FORM).commit();
    //IntentIntegrator.forSupportFragment(this).initiateScan();
}

Answer 1

try to do this may be it help you

When you are calling from main activity

 private void callFragment(Fragment fragment, String tag) {
        FragmentTransaction transaction = this.getSupportFragmentManager().beginTransaction();
        transaction.replace(R.id.mainFragment, fragment, tag);
        transaction.commit();
    }

When you are calling from same Fragment (ScanFragment) then call this and do all camera stop n other stuff before this

private void callScanFragment(String tag) {
    // Reload current fragment
    Fragment frg = null;
    frg = getSupportFragmentManager().findFragmentByTag(tag);
    final FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
    ft.detach(frg);
    ft.attach(frg);
    ft.commit();
}

Answer 2

I made use of this gradle compile I found on Github, extremely efficient and works brilliantly

compile 'com.edwardvanraak:MaterialBarcodeScanner:0.0.6-ALPHA'

Then the code to start the scan and get the value is as such:

Barcode barcodeResult;
TextView result;

private void startScan() {
    /**
     * Build a new MaterialBarcodeScanner
     */
    result = (TextView)findViewById(R.id.result);

    final MaterialBarcodeScanner materialBarcodeScanner = new MaterialBarcodeScannerBuilder()
            .withActivity(MainActivity.this)
            .withEnableAutoFocus(true)
            .withBleepEnabled(true)
            .withBackfacingCamera()
            .withText("Scanning...")
            .withResultListener(new MaterialBarcodeScanner.OnResultListener() {
                @Override
                public void onResult(Barcode barcode)
                {
                    barcodeResult = barcode;
                    result.setText(barcode.rawValue);
                }
            })
            .build();
    materialBarcodeScanner.startScan();
}

I hope that this helps