fix: capture with viewTag

Author: Tweenkie

android/src/main/java/com/documentscanner/DocumentScannerModule.java

@@ -22,8 +22,19 @@ public String getName() {
     }
 
     @ReactMethod
-    public void capture(){
-        MainView view = MainView.getInstance();
-        view.capture();
+    public void capture(final int viewTag) {
+        final ReactApplicationContext context = getReactApplicationContext();
+        UIManagerModule uiManager = context.getNativeModule(UIManagerModule.class);
+        uiManager.addUIBlock(new UIBlock() {
+            @Override
+            public void execute(NativeViewHierarchyManager nativeViewHierarchyManager) {
+                try {
+                    MainView view = (MainView) nativeViewHierarchyManager.resolveView(viewTag);
+                    view.capture();
+                } catch (Exception e) {
+                    e.printStackTrace();
+                }
+            }
+        });
     }
 }

src/index.tsx

@@ -1,12 +1,14 @@
 import React from 'react'
 import {
   DeviceEventEmitter,
+  findNodeHandle,
+  NativeModules,
   Platform,
   requireNativeComponent,
-  ViewStyle
-} from 'react-native'
+  ViewStyle } from 'react-native'
 
 const RNPdfScanner = requireNativeComponent('RNPdfScanner')
+const ScannerManager: any = NativeModules.RNPdfScannerManager
 
 export interface PictureTaken {
   rectangleCoordinates?: object;
@@ -91,15 +93,27 @@ class PdfScanner extends React.Component<PdfScannerProps> {
   }
 
   capture () {
-    let native: any = this.ref.current
-    if (native) { native.capture() }
+    if (this._scannerHandle) {
+      ScannerManager.capture(this._scannerHandle)
+    }
   }
 
-  ref = React.createRef();
+  _scannerRef: any = null;
+  _scannerHandle: number | null = null;
+  _setReference = (ref: any) => {
+    if (ref) {
+      this._scannerRef = ref
+      this._scannerHandle = findNodeHandle(ref)
+    } else {
+      this._scannerRef = null
+      this._scannerHandle = null
+    }
+  };
+
   render () {
     return (
       <RNPdfScanner
-        ref={this.ref}
+        ref={this._setReference}
         {...this.props}
         onPictureTaken={this.sendOnPictureTakenEvent.bind(this)}
         onRectangleDetect={this.sendOnRectangleDetectEvent.bind(this)}