我正在用我的应用程序拍照,调用了委托(delegate)方法,图像保存在库中,但是日志中出现崩溃错误:
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '+[NSInvocation invocationWithMethodSignature:]: method signature argument cannot be nil'
*** Call stack at first throw:
(
0 CoreFoundation 0x33ac0987 __exceptionPreprocess + 114
1 libobjc.A.dylib 0x3347b49d objc_exception_throw + 24
2 CoreFoundation 0x33a6b05d +[NSInvocation invocationWithMethodSignature:] + 340
3 PhotoLibrary 0x3038da11 __-[PLAssetsSaver _createWriteImageCompletionBlockWithImage:target:selector:contextInfo:]_block_invoke_1 + 96
4 PhotoLibrary 0x3038d7cd __-[PLAssetsSaver _saveImage:imageData:properties:completionBlock:]_block_invoke_2 + 56
5 PhotoLibrary 0x3038de87 __-[PLAssetsSaver queueJobData:requestEnqueuedBlock:completionBlock:imagePort:previewImagePort:]_block_invoke_2 + 122
6 libSystem.B.dylib 0x33c32680 _dispatch_call_block_and_release + 20
7 libSystem.B.dylib 0x33c32e38 _dispatch_main_queue_callback_4CF + 220
8 CoreFoundation 0x33a482ab __CFRunLoopRun + 1334
9 CoreFoundation 0x33a47c87 CFRunLoopRunSpecific + 230
10 CoreFoundation 0x33a47b8f CFRunLoopRunInMode + 58
11 GraphicsServices 0x33b0e4ab GSEventRunModal + 114
12 GraphicsServices 0x33b0e557 GSEventRun + 62
13 UIKit 0x32099329 -[UIApplication _run] + 412
14 UIKit 0x32096e93 UIApplicationMain + 670
15 MySoPrettyApp 0x00002737 main + 82
16 MySoPrettyApp 0x000026e0 start + 40
)
terminate called after throwing an instance of 'NSException'
我的代码如下:
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
UIImage *pickedImage = [[info objectForKey:UIImagePickerControllerOriginalImage] retain];
UIImageWriteToSavedPhotosAlbum (pickedImage, self, @selector(photoSaved:::), nil);
}
-(void)photoSaved:(UIImage*)image didFinishSavingWithError:(NSError*)error contextInfo:(void*)contextInfo {
if(!error){
NSLog(@"Photo saved to library!");
} else{
NSLog(@"Saving failed :(");
}
}
pickImage不是nil。
photoSaved方法在.h中声明
我也尝试了@selector(photoSaved :)和@selector(photoSaved)。
问题是什么 ?
最佳答案
获取选择器的正确方法如下,因为参数名称也是方法名称的一部分:
@selector(photoSaved:didFinishSavingWithError:contextInfo:)