Question

我已经以编程方式将按钮添加到我的视图中，但是当我在模拟器上测试时，只有工具栏在视图上可见。

我做错了什么？

我在头文件中定义了我的ui元素，并在主文件中合成，然后在viewDidLoad方法中初始化。但是有些不对劲。

我的代码如下;

#import "ViewController.h"

@implementation ViewController


@synthesize iAmLost, iAmLooking, about, howToUse,appsFromKodAtolye, exit;


- (void)viewDidLoad
{
[super viewDidLoad];

toolbar = [[UIToolbar alloc] initWithFrame:CGRectMake(0,0, 320.0, 40.0)];

iAmLost = [[UIButton alloc]initWithFrame:CGRectMake(0,0, 200.0, 10.0)]; 

iAmLooking = [[UIButton alloc ]initWithFrame:CGRectMake(0, 0, 200.0, 10.0) ];

[iAmLooking addTarget:self 
             action:@selector(iAmLookingScreen) 
   forControlEvents:UIControlEventTouchUpInside];


about = [[UIButton alloc]initWithFrame:CGRectMake(0, 0, 200.0, 10.0)];

howToUse = [[UIButton alloc]initWithFrame:CGRectMake(0, 0, 200.0, 10.0)];

exit = [[UIBarButtonItem alloc] initWithTitle:@"Exit" style:UIBarButtonItemStyleBordered  target:self action:@selector(exitApp:)];

NSArray *buttons = [[NSArray alloc] 
                    initWithObjects:exit, nil];

toolbar.items = buttons;


[self.view addSubview:iAmLost];
[self.view addSubview:iAmLooking];
[self.view addSubview:about];
[self.view addSubview:toolbar];



}

Answer 1

您将按钮放在工具栏下方，将每个项目添加到0,0。由于工具栏是您添加到子视图的最后一项，它将显示在所有按钮的顶部，因此您将无法看到按钮。

框架由4个x坐标，y坐标，高度，宽度组成

尝试更改这些

的x和y坐标

例如

toolbar = [[UIToolbar alloc] initWithFrame:CGRectMake(0,0, 320.0, 40.0)];

iAmLost = [[UIButton alloc]initWithFrame:CGRectMake(0,100, 200.0, 10.0)]; 

iAmLooking = [[UIButton alloc ]initWithFrame:CGRectMake(0, 200, 200.0, 10.0) ];

您还应注意，您目前尚未为按钮或任何标题设置任何样式。可能值得设置标题或背景颜色，以便您可以实际查看屏幕上放置的按钮并告诉哪个按钮。

Answer 2

由于您将工具栏添加为最后一个子视图，因此所有按钮都位于工具栏下方。您必须将按钮添加为工具栏的子视图。另请注意，您将所有按钮放在同一位置。

Answer 3

您有四个按钮和一个工具栏。工具栏的框架完全正确，即

       (0, 0, 320.0, 40.0)

但对于按钮，您为所有按钮提供相同的坐标，因此它是重叠的。更好的是你会改变按钮坐标。如果要在工具栏上添加这些按钮，请正确设置坐标并使用

     [toolBar addSubView: button];

Answer 4

简单，只需检查原点x＆amp; y为每个按钮

UIToolbar* toolbar = [[UIToolbar alloc] initWithFrame:CGRectMake(0,0, 320.0, 40.0)];

    UIButton *iAmLost = [[UIButton alloc]initWithFrame:CGRectMake(5,50, 200.0, 10.0)];
    iAmLost.backgroundColor = [UIColor redColor];
    UIButton * iAmLooking = [[UIButton alloc ]initWithFrame:CGRectMake(0, 70, 200.0, 10.0) ];

    [iAmLooking addTarget:self
                   action:@selector(iAmLookingScreen)
         forControlEvents:UIControlEventTouchUpInside];


    UIButton * about = [[UIButton alloc]initWithFrame:CGRectMake(0, 90, 200.0, 10.0)];
    about.backgroundColor = [UIColor greenColor];

   UIButton *  howToUse = [[UIButton alloc]initWithFrame:CGRectMake(0, 120, 200.0, 10.0)];
    howToUse.backgroundColor = [UIColor blackColor];

  UIBarButtonItem*  exit = [[UIBarButtonItem alloc] initWithTitle:@"Exit" style:UIBarButtonItemStyleBordered  target:self action:@selector(exitApp:)];

    NSArray *buttons = [[NSArray alloc]
                        initWithObjects:exit, nil];

    toolbar.items = buttons;


    [self.view addSubview:iAmLost];
    [self.view addSubview:iAmLooking];
    [self.view addSubview:howToUse];
    [self.view addSubview:about];
    [self.view addSubview:toolbar];

在视图中看不到按钮

4 个答案: