Question

我正在尝试创建一个＆＃34;帮助类＆＃34;动画UI元素，但我没有成功。我应该说我还是iOS编程的初学者，我喜欢以编程方式做任何事情。

我正在做的是：

 Animator *anim;
 myButton = [UIButton buttonWithType:UIButtonTypeRoundedRect]; 
[myButton addTarget:self action:@selector(addToFav) forControlEvents:UIControlEventTouchUpInside];
[myButton setTitle:@"+" forState:UIControlStateNormal];
[myButton setFont:[UIFont systemFontOfSize:23]];
[myButton setBackgroundColor:[UIColor greenColor]];
[myButton setFrame:CGRectMake(screenWidth * 0.9 - (SizeX / 2), screenHeight * 0.2285 - (SizeY / 2), X, Y)];
[self.view addSubview: myButton];
[anim moveButton:&myButton alongX:-100 alongY:200 withTime:1.5];

这是

Animator.h

@interface Animator : NSObject

-(void)moveButton:(UIButton*)button alongX:(int)x alongY:(int)y withTime:(float)time;
-(void)scaleButton:(UIButton*)button width:(float)width height:(float)height withTime:(float)time;

@end

Animator.m

@implementation Animator

-(void)moveButton:(UIButton*)button alongX:(int)x alongY:(int)y withTime:(float)time
{
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDelegate:self];
    [UIView setAnimationDuration:time];
    [UIView setAnimationBeginsFromCurrentState:YES];
    [button setFrame:CGRectMake(button.frame.origin.x + x, button.frame.origin.y + y, button.frame.size.width, button.frame.size.height)];
    [UIView commitAnimations];
}

-(void)scaleButton:(UIButton*)button width:(float)width height:(float)height withTime:(float)time
{
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDelegate:self];
    [UIView setAnimationDuration:time];
    [UIView setAnimationBeginsFromCurrentState:YES];
    [button setFrame:CGRectMake(button.frame.origin.x, button.frame.origin.y, button.frame.size.width * width, button.frame.size.height * height)];
    [UIView commitAnimations];
}

@end

编译器告诉它不能传递UIButton的地址，因为ARC，我不想禁用它，我甚至不知道它会有多少帮助禁用ARC。

有没有办法通过引用传递UIButton？

测试代码：

#import "ViewController.h"
#import "Animator.h"

@interface ViewController ()
{
    UIButton* myButton;
}

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib

    myButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    [myButton addTarget:self action:@selector(move) forControlEvents:UIControlEventTouchUpInside];
    [myButton setTitle:@"+" forState:UIControlStateNormal];
    [myButton setFont:[UIFont systemFontOfSize:23]];
    [myButton setBackgroundColor:[UIColor greenColor]];
    [myButton setFrame:CGRectMake(0, 0, 100, 100)];
    [self.view addSubview: myButton];

}
-(void)move
{
    Animator *anim;
    [anim moveButton:myButton alongX:-100 alongY:200 withTime:1.5];


    /*[UIView animateWithDuration:1.5 animations:^{ // animate
        myButton.frame = CGRectOffset(myButton.frame, 0, 200); // set new frame but with specified offset
    }];*/
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

Answer 1

请改用：

[anim moveButton:myButton alongX:-100 alongY:200 withTime:1.5]; // no asterisk!

请注意我相信你已经初始化的myButton：

UIButton *myButton = [[UIButton alloc] init];

A POINTER 不是对象本身。所以使用＆amp; myButton意味着：获取指针的地址！但是，如您所见，您不需要指针的地址而是按钮的地址。只需传递myButton，因为它已经是指向myButton的指针。

另一种方法

这里我有一个简单的代码片段，应该适合你。如果没有，问题出在其他地方。

-(void)moveButton:(UIButton*)button alongX:(int)x alongY:(int)y withTime:(float)time 
{
    [UIView animateWithDuration:time animations:^{ // animate
        button.frame = CGRectOffset(button.frame, x, y); // set new frame but with specified offset
    }];
}

只是提示：将方法签名更改为此

-(void)moveButton:(UIButton*)button alongX:(CGFloat)x alongY:(CGFloat)y withTime:(CGFloat)time;
-(void)scaleButton:(UIButton*)button width:(CGFloat)width height:(CGFloat)height withTime:(CGFloat)time;

希望这是您的解决方案：）

Animator *anim = [[Animator alloc] init];
[anim moveButton:myButton alongX:-100 alongY:200 withTime:1.5];

Answer 2

对于您提供的示例，我认为您实际上不需要通过引用传递按钮。 Animator上的方法采用指向UIButton和myButton的指针。如果要重新指定指针，则只需要通过引用传递对象，Animator当前不执行此操作。

我认为您只需将moveButton:&myButton更改为moveButton:myButton。

话虽如此，如果你曾经希望通过引用传递指针（通常用NSError指出params），你需要更改签名以使用双指针和像你一样使用&运算符传递。

NSFileManager remoteItemAtURL:error:方法的签名就是一个例子。

NSError *error = nil;
[[NSFileManager defaultManager] removeItemAtURL:url error:&error];

// error could now be pointing to something other than nil

（见https://developer.apple.com/library/prerelease/ios/documentation/Cocoa/Reference/Foundation/Classes/NSFileManager_Class/index.html#//apple_ref/occ/instm/NSFileManager/removeItemAtURL:error：）

通过引用传递UIButton

2 个答案: