按下UIButton時移動

Question

我正在嘗試使按下時增長的UIButton。目前，我有我的按鈕的按下事件下面的代碼（的Tim's answer提供）：

#define button_grow_amount 1.2 
CGRect currentFrame = button.frame; 
CGRect newFrame = CGRectMake(currentFrame.origin.x - currentFrame.size.width/button_grow_amount, 
           currentFrame.origin.y - currentFrame.size.height/button_grow_amount, 
           currentFrame.size.width * button_grow_amount, 
           currentFrame.size.height * button_grow_amount); 
button.frame = newFrame; 

運行然而，當這使得我的按鈕，向上移動，向左每次它按下時。有任何想法嗎？

Answer 1

您可以使用CGRectInset：

CGFloat dx = currentFrame.size.width * (button_grow_amount - 1); 
CGFloat dy = currentFrame.size.height * (button_grow_amount - 1); 
newFrame = CGRectInset(currentFrame, -dx, -dy); 

Answer 2

你需要一些圓括號在那裏我敢打賭。請記住，除法之前發生分割。

另外，CGRectMake的前兩個參數決定了按鈕在屏幕上的位置，而後兩個參數指示了尺寸。所以如果你只是想改變按鈕尺寸，只需設置最後兩個參數。

#define button_grow_amount 1.2 
CGRect currentFrame = button.frame; 
CGRect newFrame = CGRectMake((currentFrame.origin.x - currentFrame.size.width)/button_grow_amount, 
          (currentFrame.origin.y - currentFrame.size.height)/button_grow_amount, 
          currentFrame.size.width * button_grow_amount, 
          currentFrame.size.height * button_grow_amount); 

button.frame = newFrame;