如何将UIPickerView重置为索引：0，iPhone

Question

我正在尝试重置点按钮上的UIPickerView。 我的pickerview id是在运行时创建的，我已经设置了委托。 谷歌搜索后，我找到了

[pickerView reloadAllComponents];

但这会让我的应用每次到达时都会崩溃。

索引0处的对象是“从列表中选择”，然后是项目。 单击提交按钮时，我希望“从列表中选择”应保留在我的标签顶部（选定索引：0）。

这是我的代码

ViewDidload

 pickerView = [[UIPickerView alloc] init];
    pickerView.delegate = self;
    pickerView.dataSource = self;

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


 // Total rows in our component.
    -(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{
        return [nameArray count];
    }

// Display each row's data.
-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{
    return [nameArray objectAtIndex: row];
    }

// Do something with the selected row.

    -(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{
        dlbl.hidden=YES;
        NSLog(@"You selected this: %@", [nameArray objectAtIndex: row]);
        [btnSelectDesigner setTitle:[nameArray objectAtIndex: row] forState:UIControlStateNormal]; 

    }

并点击按钮：

-(IBAction)btnSubmitClicked:(id)sender{
[pickerView reloadAllComponents];
}

知道我做错了吗？

由于

Answer 1

[picker reloadAllComponents];
[picker selectRow:0 inComponent:0 animated:YES];

Answer 2

Swift版本：

picker.selectRow(0, inComponent: 0, animated: true)

Answer 3

//use this line for going at the top of the label index 0:

[picker selectRow:0 inComponent:0 animated:YES];