Merge pull request #1126 from mvpstars/feature/clear-window-background

Fix performance issue on Android: add option to clear window background when camera starts

README.md

@@ -347,6 +347,14 @@ from javascript.
 
 If set to `true`, the device will not sleep while the camera preview is visible. This mimics the behavior of the default camera app, which keeps the device awake while open.
 
+#### `Android` `clearWindowBackground`
+
+Values:
+`true`
+`false` (default)
+
+If you encounter performance issue while using a window background drawable (typically defined in theme to emulate splashscreen behavior), set this to true to automatically clear window background once camera is started.
+
 #### `Android` `permissionDialogTitle`
 
 Starting on android M individual permissions must be granted for certain services, the camera is one of them, you can use this to change the title of the dialog prompt requesting permissions.

android/src/main/java/com/lwansbrough/RCTCamera/RCTCameraView.java

@@ -24,6 +24,7 @@ public class RCTCameraView extends ViewGroup {
     private String _captureQuality = "high";
     private int _torchMode = -1;
     private int _flashMode = -1;
+    private boolean _clearWindowBackground = false;
 
     public RCTCameraView(Context context) {
         super(context);
@@ -77,6 +78,7 @@ public class RCTCameraView extends ViewGroup {
             if (-1 != this._torchMode) {
                 _viewFinder.setTorchMode(this._torchMode);
             }
+            _viewFinder.setClearWindowBackground(this._clearWindowBackground);
             addView(_viewFinder);
         }
     }
@@ -124,6 +126,13 @@ public class RCTCameraView extends ViewGroup {
         RCTCamera.getInstance().setBarCodeTypes(types);
     }
 
+    public void setClearWindowBackground(boolean clearWindowBackground) {
+        this._clearWindowBackground = clearWindowBackground;
+        if (this._viewFinder != null) {
+            this._viewFinder.setClearWindowBackground(clearWindowBackground);
+        }
+    }
+
     private boolean setActualDeviceOrientation(Context context) {
         int actualDeviceOrientation = getDeviceOrientation(context);
         if (_actualDeviceOrientation != actualDeviceOrientation) {

android/src/main/java/com/lwansbrough/RCTCamera/RCTCameraViewFinder.java

@@ -4,7 +4,9 @@
 
 package com.lwansbrough.RCTCamera;
 
+import android.app.Activity;
 import android.content.Context;
+import android.content.ContextWrapper;
 import android.graphics.Rect;
 import android.graphics.SurfaceTexture;
 import android.hardware.Camera;
@@ -41,6 +43,7 @@ class RCTCameraViewFinder extends TextureView implements TextureView.SurfaceText
     private boolean _isStarting;
     private boolean _isStopping;
     private Camera _camera;
+    private boolean _clearWindowBackground = false;
     private float mFingerSpacing;
 
     // concurrency lock for barcode scanner to avoid flooding the runtime
@@ -124,6 +127,11 @@ class RCTCameraViewFinder extends TextureView implements TextureView.SurfaceText
         RCTCamera.getInstance().setFlashMode(_cameraType, flashMode);
     }
 
+    public void setClearWindowBackground(boolean clearWindowBackground) {
+        this._clearWindowBackground = clearWindowBackground;
+    }
+
+
     private void startPreview() {
         if (_surfaceTexture != null) {
             startCamera();
@@ -180,6 +188,12 @@ class RCTCameraViewFinder extends TextureView implements TextureView.SurfaceText
                 _camera.setParameters(parameters);
                 _camera.setPreviewTexture(_surfaceTexture);
                 _camera.startPreview();
+                // clear window background if needed
+                if (_clearWindowBackground) {
+                    Activity activity = getActivity();
+                    if (activity != null)
+                        activity.getWindow().setBackgroundDrawable(null);
+                }
                 // send previews to `onPreviewFrame`
                 _camera.setPreviewCallback(this);
             } catch (NullPointerException e) {
@@ -213,6 +227,17 @@ class RCTCameraViewFinder extends TextureView implements TextureView.SurfaceText
         }
     }
 
+    private Activity getActivity() {
+        Context context = getContext();
+        while (context instanceof ContextWrapper) {
+            if (context instanceof Activity) {
+                return (Activity)context;
+            }
+            context = ((ContextWrapper)context).getBaseContext();
+        }
+        return null;
+    }
+
     /**
      * Parse barcodes as BarcodeFormat constants.
      *
@@ -500,4 +525,4 @@ class RCTCameraViewFinder extends TextureView implements TextureView.SurfaceText
         float y = event.getY(0) - event.getY(1);
         return (float) Math.sqrt(x * x + y * y);
     }
-}
+}

android/src/main/java/com/lwansbrough/RCTCamera/RCTCameraViewManager.java

@@ -86,4 +86,9 @@ public class RCTCameraViewManager extends ViewGroupManager<RCTCameraView> {
         }
         view.setBarCodeTypes(result);
     }
+
+    @ReactProp(name = "clearWindowBackground")
+    public void setClearWindowBackground(RCTCameraView view, boolean clearWindowBackground) {
+        view.setClearWindowBackground(clearWindowBackground);
+    }
 }

src/Camera.js

@@ -87,6 +87,7 @@ export default class Camera extends Component {
     onBarCodeRead: PropTypes.func,
     barcodeScannerEnabled: PropTypes.bool,
     cropToPreview: PropTypes.bool,
+    clearWindowBackground: PropTypes.bool,
     onFocusChanged: PropTypes.func,
     onZoomChanged: PropTypes.func,
     mirrorImage: PropTypes.bool,
@@ -117,6 +118,7 @@ export default class Camera extends Component {
     torchMode: CameraManager.TorchMode.off,
     mirrorImage: false,
     cropToPreview: false,
+    clearWindowBackground: false,
     barCodeTypes: Object.values(CameraManager.BarCodeType),
     permissionDialogTitle: '',
     permissionDialogMessage: '',
@@ -191,18 +193,16 @@ export default class Camera extends Component {
         message: this.props.permissionDialogMessage,
       });
 
-      // On devices before SDK version 23, the permissions are automatically granted if they appear in the manifest, 
+      // On devices before SDK version 23, the permissions are automatically granted if they appear in the manifest,
       // so check and request should always be true.
       // https://github.com/facebook/react-native-website/blob/master/docs/permissionsandroid.md
-      const isAuthorized = Platform.Version >= 23
-		      ? granted === PermissionsAndroid.RESULTS.GRANTED
-          : granted === true;
-      
+      const isAuthorized =
+        Platform.Version >= 23 ? granted === PermissionsAndroid.RESULTS.GRANTED : granted === true;
+
       this.setState({
-	      isAuthorized,
-		    isAuthorizationChecked: true
+        isAuthorized,
+        isAuthorizationChecked: true,
       });
-      
     } else {
       this.setState({ isAuthorized: true, isAuthorizationChecked: true });
     }
@@ -276,7 +276,7 @@ export default class Camera extends Component {
       mirrorImage: props.mirrorImage,
       fixOrientation: props.fixOrientation,
       cropToPreview: props.cropToPreview,
-      ...options
+      ...options,
     };
 
     if (options.mode === Camera.constants.CaptureMode.video) {