Question

我想向用户呈现每次按下来自ABC的不同字母的按钮。

因此，当它第一次点击应用程序时，用户将看到字母A，然后他们将需要按下按钮，然后他们将看到字母B等等。

我的挑战是如何在每次点击按钮时替换标题文本。我写下了一些代码，有两个函数，如果你仔细看一下，你会看到-(void)displayABC:(id)sender每次都被调用，所以每次我得到数组的第一个成员，所以第一次用户看到字母A然后它按下按钮，她/他看到字母B，这是数组的第一个成员，但每个相同的字母都被呈现，因为每次，我们加载plist文件，因此我们继续调用第一个成员数组。

任何想法如何解决？

-(void)createLoginBioButton
{
    authButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    [authButton setBounds:CGRectMake(300,300, 150, 150)];
    [authButton setCenter:CGPointMake(150, 240)];
    [self.view addSubview:authButton];
    [authButton setEnabled:true];
    [authButton setTitle:@"A" forState:UIControlStateNormal];
    [authButton setFont:[UIFont systemFontOfSize:70]];
    [authButton addTarget:self
                   action:@selector(displayABC:) 
         forControlEvents:UIControlEventAllTouchEvents];
 }

-(void)displayABC:(id)sender
{
    NSString *path = [[NSBundle mainBundle] pathForResource:@"ABC" ofType:@"plist"];
    NSArray *ABCArray = [NSArray arrayWithContentsOfFile:path];
    for (NSString *ABCValues in ABCArray){
        [authButton setTitle:ABCValues forState:UIControlStateNormal];
    }
}

Answer 1

为什么不将当前字母索引的引用保留为实例变量，并在每次触摸时递增？

Psuedo代码

@property NSArray *abcs;
@property int currentIndex;

- (void)viewDidLoad {
  [super viewDidLoad];
  self.abcs = //load it from the plist
  [self updateButtonText];
}

- (void)buttonTouched
{
  self.currentIndex++;

  if ( self.currentIndex >= self.abcs.count ) {
    self.currentIndex = 0;
  }
  [self updateButtonText];
}
- (void)updateButtonText
{
  [self.button setTitle:self.abcs[self.currentIndex] forControlState:UIControlStateNormal];
}

Answer 2

最简单的解决方案是放置一个保持跟踪索引的静态变量

-(void)createLoginBioButton
  {

    authButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    [authButton setBounds:CGRectMake(300,300, 150, 150)];
    [authButton setCenter:CGPointMake(150, 240)];
    [self.view addSubview:authButton];
    [authButton setEnabled:true];
    [authButton setTitle:@"A" forState:UIControlStateNormal];
    [authButton setFont:[UIFont systemFontOfSize:70]];
    [authButton addTarget:self action:@selector(displayABC:) forControlEvents:UIControlEventAllTouchEvents];
 }

-(void)displayABC:(id)sender
{

    static int index = 0;
    NSString *path = [[NSBundle mainBundle] pathForResource:@"ABC" ofType:@"plist"];
    NSArray *ABCArray = [NSArray arrayWithContentsOfFile:path];
    if(index < [ABCArray count])
        [authButton setTitle:[ABCArray objectAtIndex:index] forState:UIControlStateNormal];
    index++;


}

每次按下UIButton标题替换

2 个答案: