iOS 上可以使用从右到左的进度条吗？

Question

I've tried sending [UIProgressView setProgress] negative values, and that doesn't work.

Is there some other way to get a progress bar that fills from the right-hand end?

Answer 1

You could try setting the transform property of your UIProgressView to a new CGAffineTransform that rotates the view by 180 degrees and flips it vertically (to preserve the "shininess") (see CGAffineTransformMake() and CGAffineTransformRotate() ).

Something along the lines of:

UIProgressView *pv = [[UIProgressView alloc] initWithProgressViewStyle:UIProgressViewStyleBar];
pv.frame = CGRectMake(10, 100, 300, 11);
CGAffineTransform transform = CGAffineTransformMake(1, 0, 0, -1, 0, pv.frame.size.height); // Flip view vertically
transform = CGAffineTransformRotate(transform, M_PI); //Rotation angle is in radians
pv.transform = transform;
pv.progress = 0.5;

Answer 2

You can rotate the UIProgressView :

progressView.transform = CGAffineTransformMakeRotation(DegreesToRadians(180));

where DegreesToRadians is:

#define DegreesToRadians(d) ((d) * M_PI / 180.0)

To change the progress value, use positive numbers.

Answer 3

一个更简单的版本是水平翻转它。

progressView.transform = CGAffineTransformMakeScale(-1.0f, 1.0f);

Answer 4

在 iOS 9+ 中，您可以使用semanticContentAttribute ：

progressView.semanticContentAttribute = .forceRightToLeft

Answer 5

您可以将视图旋转 180°：

progressView.transform = CGAffineTransformMakeRotation(-M_PI);

Answer 6

In iOS 7 with storyboards, you can set the Progress Tint to the Track Tint and vice versa, then subtract the regular value from one and set that to the current progress. Probably better to do it the other (rotation) way, but I thought I would throw this out there.

Answer 7

迅捷回答：

progressView.transform = CGAffineTransform(rotationAngle: .pi)

Answer 8

Swift 5 : progressView.transform = CGAffineTransform(scaleX: -1.0, y: 1.0)