我正在尝试异步加载 View 。问题是要加载的 View 的框架取决于异步加载的数据。换句话说,有一些很长的计算决定了在哪里实际显示 UIView。
我知道尝试在线程中实际显示 UIView 时会出现问题,并且您应该始终将它们加载回主线程中,所以这是我一直在尝试的代码:
asyncQueue = [[NSOperationQueue alloc] init];
[asyncQueue addOperationWithBlock:^{
// Do work to load the UIViews and figure out where they should be
UIButton *test = [[UIButton alloc] initWithFrame:[self doWorkToGetFrame]];
[[NSOperationQueue mainQueue] addOperationWithBlock:^{
[self addSubview:test];
}
}];
}];
这一切都驻留在 UIView 容器中。
Best Answer-推荐答案 strong>
试试这样的:
UIButton *test = [[UIButton alloc] initWithFrame:CGRectZero];
test.hidden = YES;
test.alpha = 0.0f;
[self addSubview:test];
dispatch_queue_t downloadQueue = dispatch_queue_create("myDownloadQueue",NULL);
dispatch_async(downloadQueue, ^
{
// do work to load UIViews and calculate frame
CGRect frameButton = ...;
dispatch_async(dispatch_get_main_queue(), ^
{
test.hidden = NO;
[UIView animateWithDuration:0.4f animations:^
{
test.frame = frameButton;
test.alpha = 1.0f;
}
completion:^(BOOL finished){}];
});
});
dispatch_release(downloadQueue);
这会将您的按钮添加到主线程中,但最初使其不可见。后台工作完成后,您将使其可见并使用动画设置框架。
关于ios - 异步加载 UIViews,我们在Stack Overflow上找到一个类似的问题:
https://stackoverflow.com/questions/12373850/
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