ZXingObjc barcode scanner in a tab bar throw errors - ios

Question

i have a tab bar and navigation controller for my app. whenever i tap the scan tab, it kept throwing me Thread 1: EXC_BAD_ACCESS error on line:
ZXCapture.m
[output ZXQT(setDelegate:)ZXAV(setSampleBufferDelegate:)self
Here is my code:
tab bar:
TestScanViewController *scannerViewController=[[TestScanViewController alloc] initWithNibName:#"TestScanViewController" bundle:nil];
navigationController =[[UINavigationController alloc] initWithRootViewController:scannerViewController];
in the TestScanViewController.h:
#interface TestScanViewController : UIViewController <ZXCaptureDelegate>
#end
in the TestScanViewController.m:
#import <AudioToolbox/AudioToolbox.h>
#import <AVFoundation/AVFoundation.h>
#import "TestScanViewController.h"
#interface TestScanViewController ()
#property (nonatomic, strong) ZXCapture* capture;
#property (nonatomic, weak) IBOutlet UILabel* decodedLabel;
#end
#implementation TestScanViewController
#pragma mark - View Controller Methods
- (void)viewDidLoad {
[super viewDidLoad];
}
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
NSLog(#"%s",__PRETTY_FUNCTION__);
if (self.capture == nil) {
self.capture = [[ZXCapture alloc] init];
self.capture.delegate = self;
self.capture.rotation = 90.0f;
// Use the back camera
self.capture.camera = self.capture.back;
self.capture.layer.frame = self.view.bounds;;
[self.view.layer addSublayer:self.capture.layer];
[self.view bringSubviewToFront:self.decodedLabel];
}else{
[self.capture start];
[self.view.layer addSublayer:self.capture.layer];
}
}
- (void)viewWillDisappear:(BOOL)animated {
[super viewWillDisappear:animated];
NSLog(#"%s",__PRETTY_FUNCTION__);
[self.capture.layer removeFromSuperlayer];
[self.capture stop];
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation {
return toInterfaceOrientation == UIInterfaceOrientationPortrait;
}
#pragma mark - Private Methods
- (NSString*)displayForResult:(ZXResult*)result {
}
return [NSString stringWithFormat:#"Scanned!\n\nFormat: %#\n\nContents:\n%#", formatString, result.text];
}
#pragma mark - ZXCaptureDelegate Methods
- (void)captureResult:(ZXCapture*)capture result:(ZXResult*)result {
if (result) {
// We got a result. Display information about the result onscreen.
[self.decodedLabel performSelectorOnMainThread:#selector(setText:) withObject:[self displayForResult:result] waitUntilDone:YES];
// Vibrate
AudioServicesPlaySystemSound(kSystemSoundID_Vibrate);
}
}
- (void)captureSize:(ZXCapture*)capture width:(NSNumber*)width height:(NSNumber*)height {
}
#end
just like the examples codes from github:
https://github.com/TheLevelUp/ZXingObjC/blob/master/examples/BarcodeScanner/ViewController.m

Answer 1

I had the same problem. If you are targeting iOS version 6 or higher and using ARC, then the cause of the problem is an incomplete migration to ARC in ZXCapture.m.
Look around line 56 for this code:
#interface ZXCapture ()
#property (nonatomic, assign) dispatch_queue_t captureQueue;
#end
The assign is a leftover from before ARC days. It also causes a compiler warning, which was my clue to the solution.
To solve the problem, change the code into:
#interface ZXCapture ()
#property (nonatomic, strong) dispatch_queue_t captureQueue;
#end