如何从第一个组件选择中将数据加载到 UIPickerView 的第二个组件中

Question

我已经尝试为我的问题找到一个多星期的解决方案，但在解决此网站上的其他类似问题时都没有成功。

我的 pickerView 有多个 NSMutableArray，我正在尝试根据第一个组件的 selection 设置第二个组件的数据。我的主要问题是，当我 select 除了第一个组件中的第一个选择之外的任何其他内容时，第二个组件的数据为空。当第一个组件中的第一个选择是 selected 时，我在第二个组件中将所有数组一个接一个地放在一起，但我只希望每个组件数据有一个数组。

这是我在 ViewController.h 中的代码：

    @interface ViewController : UIViewController <UIPickerViewDataSource, UIPickerViewDelegate>

{
    NSMutableArray *maListeTrier;
    NSMutableArray *maListeTypes;
    NSMutableArray *maListeSousTypes;
    NSMutableArray *maListeSousTypes2;
    NSMutableArray *maListeSousTypes3;
    NSMutableArray *maListeSousTypes4;
    NSMutableArray *maListeSousTypes5;
}

@property NSString *selectedType;
@property NSString *selectedArray;

@property (weak, nonatomic) IBOutlet UIPickerView *pickerView;
@property (weak, nonatomic) IBOutlet UILabel *labelType;
@property (weak, nonatomic) IBOutlet UILabel *labelSousType;

这是我的 ViewController.m 代码：

@synthesize selectedType;
@synthesize selectedArray;

- (void)viewDidLoad {
    [super viewDidLoad];
    selectedType=[[NSString alloc]init];
    selectedArray=[[NSString alloc]init];

    maListeTypes = [[NSMutableArray alloc] init];
    [maListeTypes addObject:@"Type 1"];
    [maListeTypes addObject:@"Type 2"];

    maListeSousTypes=[[NSMutableArray alloc]init];
    [maListeSousTypes addObject:@"Sous-type 1"];
    [maListeSousTypes addObject:@"Sous-type 2"];
    [maListeSousTypes addObject:@"Sous-type 3"];
    [maListeSousTypes addObject:@"Sous-type 4"];
    [maListeSousTypes addObject:@"Sous-type 5"];

    maListeSousTypes2=[[NSMutableArray alloc]init];
    [maListeSousTypes addObject:@"22222"];
    [maListeSousTypes addObject:@"22222"];
    [maListeSousTypes addObject:@"22222"];
    [maListeSousTypes addObject:@"22222"];
    [maListeSousTypes addObject:@"22222"];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

//Méthode pour déterminer le nombre de colonnes dans chaque picker view
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {
    return 2;
}

//Méthode pour déterminer le nombre de rangées dans chaque picker view
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {
    if(component==0){
        return [maListeTypes count];
    }
    else if(component==1){
        if([selectedType isEqualToString:@"Type 1"]){
            return [maListeSousTypes count];
        }
        else if([selectedType isEqualToString:@"Type 2"]){
            return [maListeSousTypes2 count];
        }
        else{
            return 0;
        }
    }
    else{
        return 0;
    }
}

//Méthode pour indiquer quoi afficher comme choix dans chaque picker view
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {
    if(component==0){
        return [maListeTypes objectAtIndex:row];
    }
    else{
        if([selectedType isEqualToString:@"Type 1"]){
            return [maListeSousTypes objectAtIndex:row];
        }
        else{
            return [maListeSousTypes2 objectAtIndex:row];
        }
    }
}

//Méthode pour indiquer quelle action va se produire lorsqu'on clique sur un des choix des picker views
-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{
    if(component==0){
        selectedType=[maListeTypes objectAtIndex:row];
        [pickerView reloadAllComponents];
        _labelType.text=[maListeTypes objectAtIndex:[pickerView selectedRowInComponent:0]];
    }
    else if(component==1){
        _labelSousType.text=[maListeSousTypes objectAtIndex:[pickerView selectedRowInComponent:1]];
    }
}

当我的第一个组件 selection 是首选 "Type 1" 时，在我的第二个组件中，我看到了来自 NSMutableArray "maListeSousTypes" 和 "maListeSousTypes2" 的数据，就像这里一样: Screenshot

当 "Type 2" 从第一个组件 select 编辑时，我的第二个组件是空的。

Answer 1

这必须比您正在做的更简单。让我通过一个简单的例子向您展示我是如何做到的：

@interface ViewController () <UIPickerViewDataSource, UIPickerViewDelegate>

@property (strong, nonatomic) IBOutlet UIPickerView *pickerView;

@property (nonatomic, strong) NSArray *leftComponentItems; // Items from this array will populate the left component
@property (nonatomic, strong) NSArray *rightComponentItemsA; // Items from this array will populate the right component, when the 1st row of the left component is selected
@property (nonatomic, strong) NSArray *rightComponentItemsB; // Items from this array will populate the right component, when the 2nd row of the left component is selected

@property (nonatomic, assign) NSInteger selectedLeftRow; // This keeps track of the selected row on the left component (you could take that from the datasource as well)

@end

然后在您的实施中：

@implementation ViewController 

- (void)viewDidLoad {
    [super viewDidLoad];

    self.selectedLeftRow = 0;

    self.leftComponentItems = @[@"first", @"second"];

    self.rightComponentItemsA = @[@"A1", @"A2", @"A3", @"A4", @"A5"];
    self.rightComponentItemsB = @[@"B1", @"B2", @"B3", @"B4", @"B5", @"B6", @"B7"];
}

-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {
    return 2; // We have left & right components, this will always be "2"
}

-(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {
    if (component == 0) {
        return self.leftComponentItems.count;
    }

    if (component == 1) {
        if (self.selectedLeftRow == 0) {
            return self.rightComponentItemsA.count;
        } else {
            return self.rightComponentItemsB.count;
        }
    }

    return 0;
}

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

    if (component == 0) {
        return self.leftComponentItems[row];
    }

    if (component == 1) {
        if (self.selectedLeftRow == 0) {
            return self.rightComponentItemsA[row];
        } else {
            return self.rightComponentItemsB[row];
        }
    }

    return @"default";

}

-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
    if (component == 0) {
        self.selectedLeftRow = row; // We keep track of the selected row
        [pickerView reloadComponent:1]; // When we select a row in the left component, update the data on the right component
    }
}

@end

有什么不明白的地方尽管问。

如何从第一个组件选择中将数据加载到 UIPickerView 的第二个组件中

How to load data in second component of UIPickerView from first component selection

objective-c

uipickerview

ios

xcode7