如何使我的圖像中的中心IOS水平

Question

這裏是我的形象：

Obj *obj = ... obj has imageHref which is NSString 

UIImage *image = [UIImage imageNamed:[NSString stringWithFormat:obj.imageHref]]; 
[image drawInRect:CGRectMake(0, 0, image.size.width, image.size.height)]; 

取決於圖像大小我無法弄清楚如何居中，任何想法？

這是所有裏面的方法：

- (void)drawRect:(CGRect)rect {  
    Obj *obj = ... obj has imageHref which is NSString 

    UIImage *image = [UIImage imageNamed:[NSString stringWithFormat:obj.imageHref]]; 
    [image drawInRect:CGRectMake(0, 0, image.size.width, image.size.height)]; 

    NSLog(@"%f", rect.size.width); 
    NSLog(@"%f", rect.size.height); 
} 

凡rect.size.width打印320.000000和rect.size.height打印416.000000

Answer 1

[image drawInRect:CGRectMake((self.view.frame.size.width/2) - (image.size.width/2), 
          (self.view.frame.size.height/2) - (image.size.height/2), 
          image.size.width, 
          image.size.height)]; 

編輯：

因爲你已經在一個UIView：

[image drawInRect:CGRectMake((self.frame.size.width/2) - (image.size.width/2), (self.frame.size.height/2) - (image.size.height/2), image.size.width, image.size.height)]; 

Answer 2

這個或者非常類似的東西應該水平居中。

CGPoint centerImageView = imageView.center; 
centerImageView.x = self.view.center.x; 
ImageView.center = centerImageView; 

Answer 3

有可能在.H類文件@interface之前添加這樣一個宏
#define COUNTMID(X,Y) (float) (X-Y)/2
，然後用它的代碼
float center COUNTMID(ParentView.frame.width,ChildView.frame.width)
把你的ChildView鑑於在ParentView的水平中心
我還做了一個方法，使一幀ChildView被放置在ParentView的中心：

-(CGRect) CenterFrameOfView:(UIView *) ParentView forView:(UIView *) ChildView 
{ 
    CGRect result = CGRectMake(COUNTMID(ParentView.frame.size.width,ChildView.frame.size.width),COUNTMID(ParentView.frame.size.height,ChildView.frame.height),ChildView.frame.size.width,ChildView.frame.size.height); 
    return result; 
} 

或用SETFRAME

-(void) CenterFrameOfView:(UIView *) ParentView forView:(UIView *) ChildView 
{ 
    CGRect result = CGRectMake(COUNTMID(ParentView.frame.size.width,ChildView.frame.size.width),COUNTMID(ParentView.frame.size.height,ChildView.frame.height),ChildView.frame.size.width,ChildView.frame.size.height); 
    [ChildView setFrame:result]; 
} 

希望它可以幫助