objective-c - 错误: incompatible types in assignment

Question

我正在编写一些 Objective-C 代码，但我不明白为什么这不起作用:

buttonRect = CGRectMake(0,0,100.0,100.0);//error:incompatible types in assignment
CGRect newFrame = CGRectInset(buttonRect, -0.2, -0.2);//error:incompatible type for argument 1 of CGRectInset
button.frame = newFrame;

buttonRect是一个在我的类中定义为实例变量的CGRect，而button是一个也定义为实例变量的UIButton。为什么这不起作用？我的头文件:

//
//  MyViewController.h
//  HelloWorld
//
//  Created by RCIX on 7/10/09.
//  Copyright 2009 __MyCompanyName__. All rights reserved.
//

#import <UIKit/UIKit.h>


@interface MyViewController : UIViewController {
    UITextField *textField;
    UILabel *label;
    NSString *string;
    UIButton *button;
    CGRect *buttonRect;
}

@property (nonatomic, assign) CGRect *buttonRect;
@property (nonatomic, retain) IBOutlet UITextField *textField;
@property (nonatomic, retain) IBOutlet UILabel *label;
@property (nonatomic, retain) IBOutlet UIButton *button;
@property (nonatomic, retain) NSString *string;

- (IBAction)helloButtonDown:(id)sender;
- (IBAction)helloButtonUp:(id)sender;

@end

Answer 1

buttonRect 被声明为 CGRect * — 即指向 CGRect 的指针。去掉碎片，一切都会好起来的。