[英]Problem with UIImageView loading via OperationQueue
我使用NSOperationQueue加载UIImageView。
负载从Internet上获取图像,然后将其添加到图像视图。 我的问题是该方法完成了,但是大约需要3秒钟后,图像视图才能实际显示图像或从超级视图中删除图像视图...
- (void)viewDidLoad { NSLog(@"AirportDetailView: viewDidLoad");
[super viewDidLoad];
[self.activity startAnimating];
self.queue = [NSOperationQueue new];
NSInvocationOperation *operation = [[NSInvocationOperation alloc] initWithTarget:self selector:@selector(loadImage) object:NULL];
[self.queue addOperation:operation];
[operation release];
}
-(void)loadImage {
[myAp ImageForAp];
NSLog(@"ImageFor Ap Ended, %@",myAp.ApDiagram);
[self.activity stopAnimating];
if (myAp.ApDiagram==NULL) {
NSLog(@"Finally Gets Here");
[self.Diagram removeFromSuperview];
}
else {
NSLog(@"Finally Gets Here with Diag");
[self.Diagram setBackgroundImage:myAp.ApDiagram forState:UIControlStateNormal];
}
}
NSLOG显示前两个日志语句之间的延迟大约3秒,无法理解原因。
更新了我的最新代码……
-(void)loadImage {
[myAp ImageForAp];
NSLog(@"ImageFor Ap Ended, %@",myAp.ApDiagram);
[self performSelectorOnMainThread:@selector(UpdateUI) withObject:nil waitUntilDone:NO];
}
-(void)UpdateUI {
[self.activity stopAnimating];
if (myAp.ApDiagram==NULL) {
NSLog(@"Finally Gets Here");
[self.Diagram removeFromSuperview];
}
else {
NSLog(@"Finally Gets Here with Diag");
[self.Diagram setBackgroundImage:myAp.ApDiagram forState:UIControlStateNormal];
}
}
确保在主线程上运行loadImage
方法。 所有UI操作都需要在主线程上进行才能正常工作。 您的代码将需要看起来与此相似。
-(void)loadImage {
[myAp ImageForAp];
[self performSelectorOnMainThread:@selector(UpdateUI) withObject:nil waitUntilDone:NO];
}
-(void)UpdateUI {
[self.activity stopAnimating];
if (myAp.ApDiagram==NULL) {
[self.Diagram removeFromSuperview];
}
else {
[self.Diagram setBackgroundImage:myAp.ApDiagram forState:UIControlStateNormal];
}
}
viewDidLoad内部也可能发生内存泄漏。
self.queue = [NSOperationQueue new];
应该更改为
self.queue = [[[NSOperationQueue alloc] init] autorelease];
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