这是我的代码:
-(IBAction)saveDownloadedImage
{
NSLog(@"Test"); EXECUTED
indicatorView.hidden = NO; NOT EXECUTED
[indicatorView startAnimating]; NOT EXECUTED
[statusLabel setText:@"WHY?"]; NOT EXECUTED
[currentPicture setImage:[imageView image]]; EXECUTED
ImageFileManager *fileManager = [[ImageFileManager alloc] init]; EXECUTED
[fileManager saveImageToDisk:currentPicture]; EXECUTED
indicatorView.hidden = YES;
[statusLabel setText:@"Image saved successfully."]; EXECUTED
saveButton.enabled = NO; EXECUTED
}
保存过程大约需要5秒。所以在 UI 中看到该指示器是正常的。但什么也没发生!任何想法?
一切都被执行了。你的问题是saveImageToDisk
调用是同步的,您从 UI 线程调用它。当您阻塞 UI 线程时,不会重新绘制任何内容。指示器已显示,但无法绘制到屏幕上,直到IBAction
当它再次被隐藏时返回。
您必须异步调用保存方法。
阻塞 UI 线程从来都不是一个好主意。
编辑:请参阅以下问题的答案以获得正确的解决方案:ios 异步调用数据库
Edit2:可能的解决方案之一(未测试)
-(IBAction)saveDownloadedImage {
indicatorView.hidden = NO; //Note you can use hidesWhenStopped property for this
[indicatorView startAnimating];
[statusLabel setText:@"BECAUSE..."];
[currentPicture setImage:[imageView image]];
[NSThread detachNewThreadSelector:@selector(save) toTarget:self withObject:nil]
}
- (void)save {
@autoreleasepool {
ImageFileManager *fileManager = [[ImageFileManager alloc] init];
[fileManager saveImageToDisk:currentPicture];
[self performSelectorOnMainThread:@selector(updateUI) withObject:nil waitUntilDone:NO];
}
}
- (void)updateUI {
indicatorView.hidden = YES;
[statusLabel setText:@"Image saved successfully."];
saveButton.enabled = NO;
}
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