too slow when pop from the scanner page

[222xiaohuan]

Hi Thanks for providing this awesome component, I already implemented this into our project, it is working! however we met a problem when running the app on android device, it is too slow when call " this.props.navigator.pop();" on the scanner page. is there any method to improve the performance? thanks very much. will attach some screenshots for your information. the fps is very low.

Best Regards & Thanks Emily

[222xiaohuan]

@andreaskeller can you please help to have a look at this problem? thanks very much!

[Cocoon-break]

@222xiaohuan you can use a view to fix it. like this
let content if (this.state.backing) { content = <View style={{flex:1,backgroundColor:'rgba(0,0,0,0.6)'}}/> } else { content = <BarcodeScanner onBarCodeRead={this._onBarCodeRead} style={{height: screenHeight,flex:1}} torchMode={'off'} cameraType={'back'} /> }

onPress back you can change state on backing and then setTimeout to pop this scene.

[jqn]

Does anyone have a better solution?

[namxam]

I am doing almost the same… displaying a black screen with a loading animation. And then I replace it with the actual camera with

InteractionManager.runAfterInteractions(() => {
  // Start scanner preview as soon as page transitions have finished
  this.enable();
});

[jqn]

I'll give it a try, thanks @namxam.

[liuyimx]

@222xiaohuan 我也遇到了同样的问题，你现在使用什么解决方法，可以告诉我吗？

[liuyimx]

@222xiaohuan @Cocoon-break 当此问题出现之后，我同时再使用其他camera相关的插件，例如react-native-image-picker，这时候react-native-image-picker也会变得很慢，我就得这可能和资源没有释放干净有关。

[222xiaohuan]

@liuyimx 你解决了吗？我还没有解决，上面的方法你试了没，我一会试试看。这个性能老大完全不能接受T_T

[liuyimx]

@222xiaohuan 上面的方法我试了，先给个loading页面然后pop，视觉上pop没有卡顿，但是使用了此插件还是会导致react-native-image-picker及整个app变慢，另外 #47 问题依然存在。最近有个新插件叫 react-native-barcode-scanner-google，我试过貌似还不能用。现在我们正在改这个插件希望可以解决android的扫码问题。

[222xiaohuan]

@Cocoon-break your method works, thanks :)

[someok]

@Cocoon-break Your method will crash the app, and throw exception:

java.lang.RuntimeException: Camera is being used after Camera.release() was called

[someok]

BarcodeScannerManager add stopCamera method expose to js:

@Nullable
    @Override
    public Map<String, Integer> getCommandsMap() {
        return MapBuilder.of("stopCamera", COMMAND_STOP_CAMERA);
    }

    @Override
    public void receiveCommand(BarcodeScannerView root, int commandId, @Nullable ReadableArray args) {
        if (commandId == COMMAND_STOP_CAMERA) {
            root.stopCamera();
        }
    }

BarcodeScannerView JS:

stopCamera() {
        UIManager.dispatchViewManagerCommand(
            findNodeHandle(this),
            UIManager.RNBarcodeScannerView.Commands.stopCamera,
            [],
        );
    }

We can use it like this:

componentWillMount() {
        InteractionManager.runAfterInteractions(() => {
            this.setState({
                showOverlay: false,
                showBarcodeScanner: true,
            });
        });
    }

_onBackHandler = () => {
        this.setState({
            showOverlay: true
        }, () => {
            this.scanner.stopCamera();
            this.timeout = setTimeout(() => {
                this.props.router.pop();
            }, 1000);
        });

        return true;
    };

[222xiaohuan]

@someok thanks, nice job, I finally added some release and start methods in module to solve this problem, will try your method later.

[LitbLeo]

@222xiaohuan 你解决了这个问题么？我也遇到了同样的问题，我尝试使用了someok的方法但是没作用。 如果你解决了可以告知一下吗？谢谢！

[jqn]

Just an update to @someok comment for those of us who don't speak java. This code should be in: android/src/main/java/com/eguma/barcodescanner/BarcodeScannerManager.java

    @Override
    public Map<String, Integer> getCommandsMap() {
        return MapBuilder.of("stopCamera", COMMAND_STOP_CAMERA);
    }

    @Override
    public void receiveCommand(BarcodeScannerView root, int commandId, @Nullable ReadableArray args) {
        if (commandId == COMMAND_STOP_CAMERA) {
            root.stopCamera();
        }
    }```

[leonacky]

@Cocoon-break I have do it like you, but on some devices(Galaxy S7 Edge) will get error, have a black screen in the bottom, all animation is slow down.

[daffy6537]

@someok where the variable ReadableArray?