iphone - 如何在选取器视图 iOS 中设置文本对齐方式

Question

我需要在选择器视图中设置文本的对齐方式，但我的解决方案不起作用。到目前为止，这是我的代码。我使用数组在选择器视图上存储值。

- (void)viewDidLoad{

[super viewDidLoad];

self.source = [[NSMutableArray alloc]
               initWithObjects:@"  5   Minutes", @"10   Minutes", @"15   Minutes", @"20   Minutes",@"25   Minutes",@"30   Minutes",@"35   Minutes",@"40   Minutes",@"45   Minutes",@"50   Minutes",@"55   Minutes",@"60   Minutes", nil];

self.picker = [[UIPickerView alloc] initWithFrame:CGRectMake(0.0, 275.0, 320.0, 120.0)];


self.picker.delegate = self;
self.picker.dataSource = self;

[self.view addSubview:self.picker];
[self.picker selectRow:2 inComponent:0 animated:YES];}

然后，

- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {
return [source objectAtIndex:row];
}

- (NSInteger)numberOfComponentsInPickerView:
(UIPickerView *)pickerView
{
 return 1;
}

- (NSInteger)pickerView:(UIPickerView *)pickerView
numberOfRowsInComponent:(NSInteger)component
{
return [source count];
}

但是，它在显示值时工作正常。但是当我在中心对齐文本时，选择器视图变为空，而不是显示文本（选择器视图上的值）。这是关于我如何在中心对齐的代码。

- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component 
reusingView:(UIView *)view
{
UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 300, 37)];
 //label.text = [NSString stringWithFormat:@"something here"];
label.textAlignment = UITextAlignmentCenter;
label.backgroundColor = [UIColor clearColor];
return label;
}

这可能是什么解决方案？请帮我解决这个问题。

谢谢。

Answer 1

我完成了在 tableView 中心显示 UIlabel 文本的代码，例如：-

- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view
{
UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 300, 37)];

        if (component == 0) {

            label.font=[UIFont boldSystemFontOfSize:22];
            label.textAlignment = UITextAlignmentCenter;
            label.backgroundColor = [UIColor clearColor];

        label.text = [NSString stringWithFormat:@"%@", [source objectAtIndex:row]];
        label.font=[UIFont boldSystemFontOfSize:22];

        }
    [label autorelease];
    return label;
 }

代码输出是

Answer 2

对于 swift 3，我们可以使用

label.textAlignment = NSTextAlignment.center

Answer 3

使用此代码而不是您的代码..

-(UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view{

    UIView *viewTemp = [[[UIView alloc]initWithFrame:CGRectMake(0, 0, 300, 44)]autorelease];
    [viewTemp setBackgroundColor:[UIColor clearColor]];

    UILabel *lbl = [[[UILabel alloc]initWithFrame:CGRectMake(5, 0, 300, 37)]autorelease];
    [lbl setBackgroundColor:[UIColor clearColor]];
    [lbl setFont:[UIFont boldSystemFontOfSize:22]];
    lbl.text = @"Some Text";
    [lbl setTextAlignment:UITextAlignmentCenter];
    [viewTemp addSubview:lbl];
    return viewTemp;
}

在这里，我返回一个UIView，我在其中添加了UILable上面的代码，以便您的整个视图显示UILable正确，并且设置 backGroundColorUIView是清晰的，因此它的显示布局为UIPickerView.

我还在 this 中显示星形文本UIPickerView。

见图片波纹管..

Answer 4

尝试这个：

label.textAlignment = NSTextAlignmentCenter;