选择器作为IOS中的参数

Question

我想为每个创建的按钮引发一个不同的方法.我尝试在viewDidLoad中调用"FirstImage"方法,但它不起作用.

我在ViewDidLoad中的选择器有问题.没有识别"FirstImage"这是一个没有参数的void方法.

ViewController.m

- (void)createFirstButton:(NSString *)myName: (SEL *)myAction{
    UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    [btn        addTarget:self
                action:@selector(myAction)
                forControlEvents:UIControlEventTouchUpInside];
    [btn setTitle:myName forState:UIControlStateNormal];
    btn.frame = CGRectMake(20, 916, 120, 68);
    [self.view addSubview:btn];
}

- (void)viewDidLoad{
    [self createFirstButton:@"First" myAction:[self FirstImage]];
}

我做了什么(我将"CreateFirstButton"更改为"CreateButton"):

ViewControler.m

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

@synthesize myHeight;
@synthesize myWidth;
@synthesize myX;
@synthesize myY;

- (void)createButton:(NSString *)myName:(SEL)myAction:(NSUInteger)my_x:(NSUInteger)my_y:(NSUInteger)my_width:(NSUInteger)my_height
{
    UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    [btn    addTarget:self
            action:myAction
            forControlEvents:UIControlEventTouchUpInside];
    [btn setTitle:myName forState:UIControlStateNormal];
    btn.frame = CGRectMake(my_x, my_y, my_width, my_height);
    [self.view addSubview:btn];
}

- (void)myXcrementation{
    myX = myX + 150; 
}

- (void)viewDidLoad{
    myX = 20; myY = 916; myWidth = 120; myHeight = 68;
    [self createButton:@"First":@selector(FirstImage):myX:myY:myWidth:myHeight];
    [self myXcrementation];
    [self createButton:@"Previous":@selector(PreviousImage):myX:myY:myWidth:myHeight];
    [self myXcrementation];
    [self createButton:@"Pause":@selector(PauseImage):myX:myY:myWidth:myHeight];
    [self myXcrementation];
    [self createButton:@"Next":@selector(NextImage):myX:myY:myWidth:myHeight];
    [self myXcrementation];
    [self createButton:@"Last":@selector(LastImage):myX:myY:myWidth:myHeight];
}

- (void)FirstImage{
    current = 0;
    [self SetImage];
}

-(void)SetImage{
    [myImageView setImage: [myArray objectAtIndex:(current)]];
}

@end

ViewController.h

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController{
}

@property(assign, nonatomic) NSUInteger myHeight;
@property(assign, nonatomic) NSUInteger myWidth;
@property(assign, nonatomic) NSUInteger myX;
@property(assign, nonatomic) NSUInteger myY;

@end 

我再次编辑了这篇文章,没有更多的错误.特别感谢大家.我花时间了解:)

Answer 1

您必须@selector按如下方式使用

[self createFirstButton:@"First" myAction:@selector(FirstImage)];

那你的签名是错的,因为SEL不应该是指针.

更改

- (void)createFirstButton:(NSString *)myName: (SEL *)myAction{

至

- (void)createFirstButton:(NSString *)myName: (SEL)myAction{

最后myAction有类型,SEL所以你可以直接将它传递给UIButton方法,如下所示

[btn addTarget:self
     action:myAction
     forControlEvents:UIControlEventTouchUpInside];

此外,我想补充一点,使用大写的名称方法,这是一个非常糟糕的做法.