Question

我在Storyboard中有一个视图控制器，它有一堆图像，标签和按钮，正确定位了视图在初始动画后的外观。

是否有一种简单的方法可以在init上保存每个元素的原始位置（也就是说它们在故事板上的位置），以便可以采用这些元素，将它们移出视图并将它们设置为Storyboard布局/位置？

Answer 1

是的，这可以通过在数组中保存所有视图的约束，然后删除它们，并用新的屏幕外约束替换它们（我只有你想在self.view中移动所有内容时才能使用这个例子） - 如果您只想移动某些视图，则需要遍历所有self.view的约束，并仅添加与要移动到此数组的视图相关的约束。如果要将视图移动到其故事板定义的位置，请删除当前的视图，重新添加已保存的视图，并在动画块中调用layoutIfNeeded。

@interface ViewController ()
@property (weak, nonatomic) IBOutlet UIButton *bottomButton;
@property (weak, nonatomic) IBOutlet UIButton *topButton;
@property (weak, nonatomic) IBOutlet UIButton *middleButton;
@property (strong,nonatomic) NSArray *finalConstraints;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    NSDictionary *viewsDict = NSDictionaryOfVariableBindings(_bottomButton,_topButton,_middleButton);
    self.finalConstraints = self.view.constraints; // save the storyboard constraints
    [self.view removeConstraints:self.view.constraints]; // remove all the storyboard constraints
    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"[_topButton]-(-30)-|" options:0 metrics:nil views:viewsDict]];
    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:[_topButton]-(-30)-|" options:0 metrics:nil views:viewsDict]];

    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"[_middleButton]-(-30)-|" options:0 metrics:nil views:viewsDict]];
    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:[_middleButton]-(-30)-|" options:0 metrics:nil views:viewsDict]];

    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"[_bottomButton]-(-30)-|" options:0 metrics:nil views:viewsDict]];
    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:[_bottomButton]-(-30)-|" options:0 metrics:nil views:viewsDict]];

    [self performSelector:@selector(moveToFinalPositions) withObject:nil afterDelay:2];
}

- (void)moveToFinalPositions {
    [self.view removeConstraints:self.view.constraints];
    [self.view addConstraints:self.finalConstraints];
    [UIView animateWithDuration:2 animations:^{
        [self.view layoutIfNeeded];
    }];
}

动画到故事板状态/位置

1 个答案: