Question

我试图以这种方式每1.5秒更换一次UItextFieeld：

-(void)Welcome{

UITextField* WelcomeField = [[UITextField alloc] initWithFrame:CGRectMake(50,230,220,80)];
[self.view addSubview:WelcomeField];
WelcomeField.placeholder = @"Welcome";
WelcomeField.font = [UIFont fontWithName:@"Chalkduster" size:40];
[WelcomeField setBackgroundColor:[UIColor clearColor]];

NSTimer* TimeCounterWelcome = [NSTimer scheduledTimerWithTimeInterval: 1.5 target: self
                                                         selector: @selector(ChangeLanguage:) userInfo: nil repeats: YES];
}

- (IBAction)ChangeLanguage:(id)sender{

WelcomeField.placeholder = @"Goodby";


NSTimer* TimeCounterWelcome = [NSTimer scheduledTimerWithTimeInterval: 1.5 target: self
                                                         selector: @selector(ChangeLanguage2:) userInfo: nil repeats: YES];

}

- (IBAction)ChangeLanguage2:(id)sender{

WelcomeField.placeholder = @"Friend";

}

问题是我有30个单词，而且我不能重复30次代码。有更快的方法吗？

Answer 1

这样的事情会起作用：

-(void)Welcome{

UITextField* WelcomeField = [[UITextField alloc]initWithFrame:CGRectMake(50,230,220,80)];
[self.view addSubview:WelcomeField];
WelcomeField.placeholder = @"Welcome";
WelcomeField.font = [UIFont fontWithName:@"Chalkduster" size:40];
[WelcomeField setBackgroundColor:[UIColor clearColor]];

// global integer 'wordIndex'
wordIndex = 0;

// global NSArray 'allTheWords'
allTheWords = [NSArray arrayWithObjects:word1, word2, word3, etc., nil];

NSTimer* TimeCounterWelcome = [NSTimer scheduledTimerWithTimeInterval: 1.5 target: self
                                                     selector: @selector(ChangeLanguage:) userInfo: nil repeats: YES];
}

-(void)ChangeLanguage:(id)sender{
    NSString * nextWord = [allTheWords objectAtIndex:wordIndex];
    WelcomeField.placeholder = nextWord;
    wordIndex++;

    // assuming to start from beginnning again
    if(wordIndex >= 30) {
        wordIndex = 0;
    }
}

一个小样式评论：尝试使用小写字母i.s.o开始方法和变量名称。大写字母。如果您想要遵循Objective-C编码指南，那就更好了。

Answer 2

是的，有更好的方法可以做到。

定义一个包含所有30个单词的数组。在循环数组时，设置占位符并设置延迟。

Answer 3

声明一个NSArray，它保存所有30个值并每隔1.5秒循环一次，直到达到最后一个项目。

for (id object in array) {
    // do something with object
}

使用时间延迟更改UITextField文本

3 个答案: