objective-c - Why is my UIProgressBar not being updated?

Question

Here is how I am attempting to update my UIProgressView in my iOS app.

[self.progressView setProgress:3.0/10.0 animated:YES];

// check the value.
NSLog(@"Progress: %0.1f", self.progressView.progress);

Why is NSLog outputting 0.0? Shouldn't it output 0.3? The progress bar isn't changing either.

score 0 · Accepted Answer

首先，确保在主线程上设置进度值。（这self.progressView实际上是指您的UIProgressView）

如果这没有帮助，您可能需要明确地给 runloop 一些时间来赶上 UI 更改，例如使用：

NSDate* futureDate = [NSDate dateWithTimeInterval:0.001 sinceDate:[NSDate date]];
[[NSRunLoop currentRunLoop] runUntilDate:futureDate];

但是，您应该非常小心使用这样的黑客，请参阅：

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