[英]Why am i getting a black frame and not the picker?
我有这个非常简单的代码,或者至少我认为它很简单。
// Implement loadView to create a view hierarchy programmatically, without using a nib.
- (void)loadView {
CGRect rect = CGRectMake(0.0f, 20.0f, 320.0f, 216.0f);
UIPickerView *myPickerView = [[UIPickerView alloc] initWithFrame:rect];
self.view = myPickerView;
[myPickerView release];
}
我正在使用XCode运行一般的基于视图的模板。 我可以看到loadView被调用,但我得到一个黑框而不是UIPickerView。
我究竟做错了什么 ?
/ donnib
您是否实现了选择器的数据源方法? 你需要它,否则它不会显示。
链接到Apple文档: http : //developer.apple.com/library/ios/#DOCUMENTATION/iPhone/Reference/UIPickerViewDataSource_Protocol/Reference/Reference.html#//apple_ref/occ/intf/UIPickerViewDataSource
您忘记将UIPickerView的委托设置为当前视图。 加:
myPickerView.delegate = self;
...在初始化之后和查看之前。 当然,请确保将头文件设置为UIPickerView委托并实现dataSource方法。
尝试这个:
UIView *contentView = [[UIView alloc] initWithFrame: [[UIScreen mainscreen] bounds]];
UIPickerView *pickerView = [[UIPickerView alloc] initWithFrame: CGRectZero];
CGSize pickerSize = [pickerView sizeThatFits: CGSizeZero];
pickerView.frame = [self pickerFrameWithSize: pickerSize];
[pickerView setShowsSelectionIndicator: YES];
[contentView addSubview: pickerView];
[pickerView release];
[self setView: contentView];
[contentView release];
相反,覆盖的-loadView
,你应该重写-viewDidLoad
。 加载视图后,您将创建选择器并将其添加为视图控制器拥有的视图的子视图。
- (void)viewDidLoad
{
[super viewDidLoad];
CGRect rect = CGRectMake(0.0f, 20.0f, 320.0f, 216.0f);
UIPickerView *myPickerView = [[UIPickerView alloc] initWithFrame:rect];
[self.view addSubview:myPickerView];
[myPickerView release];
}
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.