为什么 UIPickerView 显示带有白色边框

Question

我添加了一个选择器视图以及数据源和委托，如下所示：

- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {
    return _datas.count;
}

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

- (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component {
CGFloat width = SCREEN_W / _datas.count;
    return width;
}

- (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component {
    return kActionPickerRowHeight;
}


- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view {
    UILabel *label = [[UILabel alloc] init];
    label.frame = CGRectMake(0, 0, SCREEN_W / _datas.count, kActionPickerRowHeight);
    label.textAlignment = NSTextAlignmentCenter;
    label.text =  [NSString stringWithFormat:@"%@",_datas[component][row]];
    label.font = [UIFont systemFontOfSize:12.f];

    label.layer.borderWidth = 1.f;
    return label;
}

但是选择器显示如下：

右边有一个150px左右的白边

我显示行的边框和选择器的边框以进行调试

Answer 1

将方法更新为

- (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component {
CGFloat width = pickerView.frame.width / _datas.count;
    return width;
}

Answer 2

我找到了导致问题的原因：我没有将选择器视图的框架设置为及时更正值。因为我在-(void)layoutSubviews中写了frame-setting的代码，而且是在dataSource的方法调用之后调用的，所以无法正确显示。于是，我加上[self layoutIfNeed]初始化后手动调用layoutSubviews，问题解决

为什么 UIPickerView 显示带有白色边框

Why UIPickerView shows with a white border

iphone

objective-c

uipickerview

ios