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Question

我想以编程方式创建10个按钮。每个按钮都有一个带有两个标签的子视图（一个字符串和一个整数）。

我在循环中创建了这10个按钮后，我想访问这两个标签。我尝试使用标签0来对NSLog标签进行操作，但它没有用。

所有这些都感觉有点笨拙，所以如果我无处可去，请纠正我：

for (int i = 0; i < 9; i++) {

    UIButton* btn = [[[UIButton alloc] initWithFrame:CGRectMake(55, i*(indexHeight+indexSpacing), indexWidth, indexHeight)] autorelease]; 
    btn.tag = i;
    [btn setBackgroundImage:nil forState:UIControlStateNormal];
    [btn    addTarget:self
            action:@selector(buttonTapped:)
  forControlEvents:UIControlEventTouchUpInside];

 // LABELS

    UILabel *btnTitle = [[[UILabel alloc] initWithFrame:CGRectMake(0, 0, indexWidth, indexHeight)] autorelease];
     btnTitle.text = @"Empty";

    UILabel *pageTitle = [[[UILabel alloc] initWithFrame:CGRectMake(190, 0, 30, indexHeight)] autorelease];
     pageTitle.text = @"x";

    [indexView addSubview:btn];
    [btn addSubview:btnTitle];
    [btn addSubview:pageTitle];
}

这是我尝试过的，问题出在哪里：

NSLog (@"Accessing label 1 in button with tag 0 in indexView: '%@'", [[indexView viewWithTag:0] btnTitle.text]);
NSLog (@"Accessing label 2 in button with tag 0 in indexView: '%@'", [[indexView viewWithTag:0] pageTitle.text]);

“UILabel created programmatically - find it again?”是我能找到的最接近的问题，但它并没有真正回答如何在btn的子视图中访问标签的问题。

Answer 1

您也可以尝试为每个标签分配一个标签，第一个标签为100，第二个标签为101，然后您的代码看起来像这样，用于检索标签

NSLog (@"Accessing label 1 in button with tag 0 in indexView: '%@'", [[indexView viewWithTag:0] viewWithTag:100].text);
NSLog (@"Accessing label 2 in button with tag 0 in indexView: '%@'", [[indexView viewWithTag:0] viewWithTag:101].text);

Answer 2

如果设置了indexHeight，indexSpacing，indexWidth，则以下内容肯定有效。

for (int i = 0; i < 9; i++) {

    UIButton* btn = [[[UIButton alloc] initWithFrame:CGRectMake(55, i*(indexHeight+indexSpacing), indexWidth, indexHeight)] autorelease]; 
    btn.tag = i;
    [btn setBackgroundImage:nil forState:UIControlStateNormal];
    [btn    addTarget:self
            action:@selector(buttonTapped:)
  forControlEvents:UIControlEventTouchUpInside];

 // LABELS

    UILabel *btnTitle = [[[UILabel alloc] initWithFrame:CGRectMake(0, 0, indexWidth, indexHeight)] autorelease];
     btnTitle.text = @"Empty";

    btnTitle.tag = i+100;
    UILabel *pageTitle = [[[UILabel alloc] initWithFrame:CGRectMake(190, 0, 30, indexHeight)] autorelease];
     pageTitle.text = @"x";
     pageTitle.tag = i+101;

    [indexView addSubview:btn];
    [btn addSubview:btnTitle];
    [btn addSubview:pageTitle];

}

for (int i = 0; i < 9; i++) {
   UILabel *btnTitle = (UILabel *)[[indexView viewWithTag:i] viewWithTag:100+i];
   UILabel *pageTitle = (UILabel *)[[indexView viewWithTag:i] viewWithTag:101+i];
   NSLog (@"btnTitle.text: '%@'", btnTitle.text);
   NSLog (@"pageTitle.text: '%@'", pageTitle.text);

}

Answer 3

1

在头文件中添加此ivar：

NSMutableArray *buttonArray;

2

在.m文件的init中初始化此数组：

buttonArray = [NSMutableArray array];
[buttonArray retain];

3

按如下方式更改for循环：

for (int i = 0; i < 9; i++) 
    {

        UIButton* btn = [[[UIButton alloc] initWithFrame:CGRectMake(55, i*(indexHeight+indexSpacing), indexWidth, indexHeight)] autorelease]; 
        btn.tag = i;
        [btn setBackgroundImage:nil forState:UIControlStateNormal];
        [btn    addTarget:self
                   action:@selector(buttonTapped:)
         forControlEvents:UIControlEventTouchUpInside];

        // LABELS

        UILabel *btnTitle = [[[UILabel alloc] initWithFrame:CGRectMake(0, 0, indexWidth, indexHeight)] autorelease];
        btnTitle.text = @"Empty";

        UILabel *pageTitle = [[[UILabel alloc] initWithFrame:CGRectMake(190, 0, 30, indexHeight)] autorelease];
        pageTitle.text = @"x";

        [indexView addSubview:btn];
        [btn addSubview:btnTitle];
        [btnTitle release]; //avoiding leaks
        [btn addSubview:pageTitle];
        [pageTitle release]; //avoiding leaks






        //The changes are here.....

        [buttonArray addObject:btn];
        [btn release];
    }

4

要从数组执行按钮（例如按钮5）：

UIButton *thisButton = (UIButton *)[buttonArray objectAtIndex:5];

5

使用此按钮执行任何操作：）

PS：你在for循环中分配那些btn对象（看起来它们不是ivars）。一旦你在for循环之外，它们将失去范围，所以你无论如何都无法访问它们。上面使用NSMutableArray的方法也解决了这个问题，因为现在你已经创建了btn并将它们添加到一个ivar数组中，因此你不会在for循环之外丢失范围。此外，如果要在其上设置自定义子视图，则应该将UIButton子类化。

如何在循环中以编程方式创建UILabel的文本

3 个答案:

1

2

3

4

5