fixed the bug: cannot restart barcode scan session

Author: cyqresig

ios/RCTBarcode/RCTBarcode/RCTBarcode.m

@@ -52,9 +52,6 @@ - (void)removeFromSuperview
 {
 //    NSLog(@"removeFromSuperview...");
 
-    [self.scanLineTimer invalidate];
-    self.scanLineTimer = nil;
-    
     [self.manager endSession];
     [super removeFromSuperview];
 }

ios/RCTBarcode/RCTBarcode/RCTBarcodeManager.m

@@ -61,6 +61,9 @@ - (id)init {
 }
 
 - (void)initializeCaptureSessionInput:(NSString *)type {
+    
+    NSLog(@"initializeCaptureSessionInput...");
+    
     dispatch_async(self.sessionQueue, ^{
 
         [self.session beginConfiguration];
@@ -84,6 +87,9 @@ - (void)initializeCaptureSessionInput:(NSString *)type {
 
 
         if ([self.session canAddInput:captureDeviceInput]) {
+            
+            NSLog(@"self.session canAddInput:captureDeviceInput...");
+            
             [self.session addInput:captureDeviceInput];
 
             self.videoCaptureDeviceInput = captureDeviceInput;
@@ -107,6 +113,9 @@ - (void)initializeCaptureSessionInput:(NSString *)type {
 //        NSLog(@"self.metadataOutput = %@", self.metadataOutput);
 
         if(self.metadataOutput == nil) {
+            
+            NSLog(@"self.metadataOutput = %@", self.metadataOutput);
+            
             AVCaptureMetadataOutput *metadataOutput = [[AVCaptureMetadataOutput alloc] init];
             self.metadataOutput = metadataOutput;
 
@@ -171,13 +180,15 @@ - (void)endSession {
         [self.session commitConfiguration];
         [self.session stopRunning];
         [self.barcode.scanLineTimer invalidate];
+        self.barcode.scanLineTimer = nil;
         for(AVCaptureInput *input in self.session.inputs) {
             [self.session removeInput:input];
         }
 
         for(AVCaptureOutput *output in self.session.outputs) {
             [self.session removeOutput:output];
         }
+        self.metadataOutput = nil;
     });
 }