如何使用动画将矩形形状更改为圆形形状

Question

I have a label:

    self.logInLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 300, 100)];
    self.logInLabel.backgroundColor = [UIColor clearColor];
    self.logInLabel.backgroundColor = Color_Circle_Outer;
    self.logInLabel.textColor = Color_Circle_Outer;
    self.logInLabel.textAlignment = NSTextAlignmentCenter;
    self.logInLabel.lineBreakMode = NSLineBreakByWordWrapping;
    self.logInLabel.numberOfLines = 1;
    self.logInLabel.font = [UIFont boldSystemFontOfSize:12*IPAD];
    self.logInLabel.text = @"Log In";
    [self addSubview:self.logInLabel];
    self.logInLabel.layer.cornerRadius   = self.frame.size.height/2.0;
    self.logInLabel.layer.borderColor    = Color_Circle_Outer.CGColor;
    self.logInLabel.layer.borderWidth    = 2*IPAD;
    self.logInLabel.layer.masksToBounds  = YES;

I want to change this shape to a Circle. I have tried:

    [UIView animateWithDuration:AnimationTime animations:^{
       self.logInLabel.layer.bounds = CGRectMake(0, 0, self.frame.size.height, self.frame.size.height);
    }];

But the shape changed immediately without animation, then the position change to center with animation. Then I tried with this:

    [UIView animateWithDuration:AnimationTime animations:^{
       self.logInLabel.bounds = CGRectMake(0, 0, self.logInLabel.frame.size.height, self.logInLabel.frame.size.height);
    }];

I have very ugly animation effect.

I do not care if this view is a label, I just want to implement changing a rectangle shape to a circle shape with an animation.

Thank you.

Answer 1

It works only CABasicAnimation not the UIView animateWithDuration

    UIView *logInLabel = [[UIView alloc] initWithFrame:CGRectMake(100, 100, 200, 200)];
    logInLabel.backgroundColor = [UIColor blackColor];
    logInLabel.layer.masksToBounds = YES;
    [self.view addSubview:logInLabel];

    CABasicAnimation *animation = [CABasicAnimation  animationWithKeyPath:@"cornerRadius"];
    animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];
    animation.fromValue = [NSNumber numberWithFloat:0.0f];
    animation.toValue = [NSNumber numberWithFloat:100.0f];
    animation.duration = 5.0;
    [logInLabel.layer addAnimation:animation forKey:@"cornerRadius"];
    [logInLabel.layer setCornerRadius:0.0];

Answer 2

From your code remove the line :

self.logInLabel.layer.cornerRadius = self.logInLabel.frame.size.height / 2.0;

and put it in an animation block like this

You can set cornerRadius of your UILabel to get a circular view.

[UIView animateWithDuration:AnimationTime animations:^{
       self.logInLabel.layer.cornerRadius = self.logInLabel.frame.size.height / 2.0f;
    }];

However, the animation will not look very good and the final frame will not be an exact circle because the height and width of your UILabel are not in 1:1 proportion.

If you still don't get the animation try to check the value of AnimationTime variable.

Answer 3

Look that might help you

[UIView animateWithDuration:0.4 animations:^{
        CGPoint center = self.logInLabel.center;
        self.logInLabel.layer.cornerRadius = self.logInLabel.frame.size.height/2;
        self.logInLabel.frame = CGRectMake(0, 0, self.logInLabel.frame.size.height, self.logInLabel.frame.size.height);
        self.logInLabel.center = center;
    }];