如何知道 UIView 正在向内侧或外侧调整大小？

Question

如何知道一个UIView正在调整大小并且框架在增加或减少（或内侧或外侧）？

例如我有一个 UIImageView（我正在使用第三方 library 来调整对象的大小）。它的当前帧是 (someX, someY, 200,50)，现在如果我以某种方式调整大小，它会将宽度更改为 300，而在另一种情况下，它会将其更改为 150。我应该能够知道，它的 increased/decreased.

Answer 1

你可以做一些Key-Value Observing。例如，如果您的 UIImageView *imageView 那么您可以：

[imageView addObserver:self forKeyPath:@"frame" options:0 context:NULL];

您还需要实现此方法才能对更改做出反应：

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
    UIImageView *imageView = (UIImageView *)object;
    // Do what you gotta do, like save the current size in 
    // an instance variable so you can compare and see increase/decrease in size
}

Answer 2

我是这样做到的，

在上面的库中添加了自定义委托 (SPUserResizableView.h)，- (void)userResizableViewIsResizing:(SPUserResizableView *)userResizableView {}

- (void)userResizableViewIsResizing:(SPUserResizableView *)userResizableView {
    id contentView = userResizableView.contentView;
    if([contentView isKindOfClass:[iOTextField class]]) {
        iOTextField *textField = (iOTextField *)contentView;        
        if([self isResizingUpWithOriginalSize:textField.referenceiOProperties.originalSize currentSize:userResizableView.frame.size withiOTextField:textField]) {
            [textField increaseFont];
        } else {
            [textField decreaseFont];
        }
    }
}

- (BOOL) isResizingUpWithOriginalSize:(CGSize)original currentSize:(CGSize)currentSize withiOTextField:(iOTextField *)textField {
    CGFloat width = (currentSize.width - original.width);
    CGFloat height = (currentSize.height - original.height);
    if(width <= 0.0f && height <= 0.0f) {
        textField.lastWidth = width;
        textField.lastHeight = height;
        return NO;
    } else if(width > textField.lastWidth) {
        if(textField.lastWidth <= 0.0f) {
            textField.lastWidth = width;
            textField.lastHeight = height;
            return NO;
        }
        textField.lastWidth = width;
        textField.lastHeight = height;
        return YES;
    }  else if(height > textField.lastHeight) {
        if(textField.lastHeight <= 0.0f) {
            textField.lastWidth = width;
            textField.lastHeight = height;
            return NO;
        }
        textField.lastWidth = width;
        textField.lastHeight = height;
        return YES;
    } else {
        textField.lastWidth = width;
        textField.lastHeight = height;
        return NO;
    }
}

在 SPUserResizableView.m class 中对这个触摸事件做一个小改动。

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {    
    if(self.delegate && [self.delegate respondsToSelector:@selector(userResizableViewIsResizing:)]) {
        [self.delegate userResizableViewIsResizing:self];
    }
}

如何知道 UIView 正在向内侧或外侧调整大小？

How to know a UIView is resizing to inner side or outer side?

resize

objective-c

uiview

ios