未从viewDidAppear加载UIPickerView

Question

我有一个UIPickerview，它是我最初在viewDidLoad中设置的。它工作得非常好。

但我希望每次从另一个视图返回时都刷新它，所以我放入了viewDidAppear

- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];


    NSLog(@"View will appear");
    [self loadthepicker];

}


-(void) loadthepicker
{

    pickerLoaderArray=[[NSMutableArray alloc] init];
    [pickerLoaderArray addObject:@"one"];
    [pickerLoaderArray addObject:@"two"];
    [pickerLoaderArray addObject:@"thee"];
    [pickerLoaderArray addObject:@"four"];

    [pickerView selectRow:0 inComponent:0 animated:NO];

}



-(NSInteger)numberOfComponentsInPickerView:(NSInteger)component
{

    return 1;

}


-(NSInteger)pickerView:(UIPickerView *)picker numberOfRowsInComponent:(NSInteger)component
{

    return [pickerLoaderArray count];

}



-(NSString *)pickerView:(UIPickerView *)picker titleForRow:(NSInteger)row forComponent:(NSInteger)component{

    return [pickerLoaderArray objectAtIndex:row];
}

好吧，我想我可能已经知道答案了：

pickerView reloadAllComponents；

我将这个添加到loadthepicker函数中，现在它工作得很好。

这是正确的做法吗？

Answer 1

你必须打电话给

[pickerView reloadAllComponents];

Answer 2

UIPickerview委托在viewDidApear方法之前调用的方法，所以你必须调用uipikerview显式的委托方法。

-(void) loadthepicker
{

pickerLoaderArray=[[NSMutableArray alloc] init];
[pickerLoaderArray addObject:@"one"];
[pickerLoaderArray addObject:@"two"];
[pickerLoaderArray addObject:@"thee"];
[pickerLoaderArray addObject:@"four"];

[self.pickerview selectRow:0 inComponent:0 animated:NO];
[self.pickerview reloadAllComponents];
}