在macOS objective-c上为NSView约束(层支持视图)制作动画

NSView *myView = [[NSView alloc] init];
[myView setTranslatesAutoresizingMaskIntoConstraints:NO];
[self.view addSubview:myView];

[NSLayoutConstraint activateConstraints:@[
    [myView.topAnchor constraintEqualToAnchor:self.view.topAnchor constant:20],
    [myView.leadingAnchor constraintEqualToAnchor:self.view.leadingAnchor constant:20],
    [myView.widthAnchor constraintEqualToConstant:100],
    [myView.heightAnchor constraintEqualToConstant:100]
]];

[NSAnimationContext runAnimationGroup:^(NSAnimationContext *context){
    context.duration = 1.0; // 动画持续时间
    myView.animator.alphaValue = 0.5; // 动画效果：改变透明度
} completionHandler:^{
    // 动画完成后的操作
}];

NSLayoutConstraint *widthConstraint = [myView.widthAnchor constraintEqualToConstant:200];
widthConstraint.active = YES;

[NSAnimationContext runAnimationGroup:^(NSAnimationContext *context){
    context.duration = 1.0;
    [myView.animator setFrameSize:NSMakeSize(200, 100)];
} completionHandler:^{
    // 动画完成后的操作
}];