不显示从标签上的选取器视图中选择的对象

Posted 2023-02-24

【中文标题】不显示从标签上的选取器视图中选择的对象

【英文标题】：Not showing the selected object from picker view on the label

【发布时间】：2016-06-13 05:34:46

【问题描述】：

I am using picker view in my application, I am selecting the object but object is not showing on the label,
Please help me

pragma mark- PICKER_VIEW_Delegate_Methods ----------------->>>>



- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView



    return 1;


// The number of rows of data

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



    if(pickerView == countryPicker)

    
        return [arrayCountry count];
    

    if(pickerView == statePicker)

    
        return [stateArray count];
    
    else return 5;

// The data to return for the row and component (column) that's being passed in

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


    if(pickerView == countryPicker)
    
        return [arrayCountry objectAtIndex:row];
    
    if(pickerView == statePicker)

    
        return  [stateArray objectAtIndex:row];
    

    return @"";


- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component


    if(pickerView == countryPicker)

    

        countryLabel.text = countryArray[row];

        countryPicker.hidden = YES;
        NSLog(@"statelabel %@",countryLabel.text);
    

    if(pickerView == statePicker)

    
        [stateLabel setText:[stateArray objectAtIndex:row]];
        statePicker.hidden = YES;
    


- (IBAction)countryList:(id)sender

    countryPicker.hidden = false;
    [countryPicker reloadAllComponents];



- (IBAction)stateList:(id)sender

    stateArray = [DictStates valueForKeyPath:countryStr];
    statePicker.hidden = false;
    stateTable.hidden = FALSE;

    [statePicker reloadAllComponents];


- (void)getCountryStatesList



    NSURLSession *session = [NSURLSession sharedSession];

    NSURLSessionDataTask *dataTask = [session dataTaskWithURL:[NSURL URLWithString:@"http://dev-demo.info.bh-in-15.webhostbox.net/dv/nationalblack/api/countrystate"] completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) 

        NSDictionary *json = [NSJSONSerialization JSONObjectWithData:data options:0 error:nil];

        NSLog(@"List : %@", json);
        dispatch_async(dispatch_get_main_queue(), ^
            [self parseCountryStates:json];
        );

    ];
    [dataTask resume];


- (void)parseCountryStates:(NSDictionary *)json


    NSArray *listing = [json objectForKey:@"listing"];

    arrayCountry = [[NSSet setWithArray:[listing valueForKey:@"country"]] allObjects];

    NSArray *states;

    NSMutableDictionary *tempStates = [NSMutableDictionary new];

    for (NSString *countryName in arrayCountry) 

        NSPredicate *predicateString = [NSPredicate predicateWithFormat:@"%K contains[cd] %@", @"country", countryName];

        NSLog(@"predicate %@",predicateString);

        states = [NSMutableArray arrayWithArray:[listing filteredArrayUsingPredicate:predicateString]];

        [tempStates setObject:states forKey:countryName];

    
    DictStates = tempStates;



now country is selected but now when i click on state button it creashed
i am sharing my crash log:

>     -[__NSCFDictionary length]: unrecognized selector sent to instance 0x7f98c9683220
>     2016-06-13 11:30:54.912 [1745:52321] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason:
> '-[__NSCFDictionary length]: unrecognized selector sent to instance
> 0x7f98c9683220'
>     *** First throw call stack:

【问题讨论】：

我认为countryLabel.text = countryArray[row];这一行应该是countryLabel.text = arrayCountry[row];

@EICaptainv2.0 感谢它的工作，但我有另一个问题，当我选择状态按钮它没有显示状态列表

【参考方案1】：

Replace Your method with

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component


    if(pickerView == countryPicker)
    
        countryLabel.text = arrayCountry[row];
        countryPicker.hidden = YES;
        NSLog(@"statelabel %@",countryLabel.text);
    
    if(pickerView == statePicker)
    
        [stateLabel setText:[stateArray objectAtIndex:row]];
        statePicker.hidden = YES;
    


Will solve your problem  :)

【讨论】：

感谢它的工作，但我在选择状态按钮时遇到另一个问题，它没有显示状态列表

你有 statePicker.hidden = YES;在您的代码中，在按钮操作上您应该隐藏为 false 并重新加载选择器视图会有所帮助

请修正 numberOfRowsInComponent ，你应该使用 else if ， insted of if, if 和 else，

点击状态按钮时崩溃，崩溃日志为：-[__NSCFDictionary length]: unrecognized selector sent to instance 0x7f98c9683220 2016-06-13 11:30:54.912 National_black[1745:52321] ** * 由于未捕获的异常“NSInvalidArgumentException”而终止应用程序，原因：“-[__NSCFDictionary 长度]：无法识别的选择器发送到实例 0x7f98c9683220”*** 第一次抛出调用堆栈：

添加异常断点并查看它崩溃的位置，根据您尝试使用字典中的方法“length”的崩溃日志，它应该与 NSString 一起使用，而不是与 NSDictionary 一起使用，