财产发生变化，但我不知道是谁做的

Question

我有一个 UIViewController （称为 AdjustViewController），它呈现另一个带有 UIPickerView 的 UIViewController （称为 SourcePickerViewController）模态。我生成 AdjustViewController 的实例，它们又创建一个 SourcePickerViewController。我创建一个 NSDictionary 并将其和一个 integer 分配给 AdjustViewController，然后它又在 SourcePickerController 中设置相同的属性代码>.这样我就可以重用控制器。 NSDictionary 在一个 UITableViewController 中设置，其中包含所有 AdjustViewController。

当一些选择器应该有 1 个组件而有些选择器应该有 2 个组件时，问题就出现了。我传递的整数称为 numberOfComponents 当我使用 numberOfComponents = 1 制作一个选择器时不知何故，它正在更改为 = 2 但我不知道如何更改。我到处都有 NSLogs ，只要调用选择器委托方法 numberOfComponentsInPickerView ，我就可以看到它发生。之前是 1，之后是 2。

显然还有更多的代码，但我认为我已经拥有所有重要的部分。但如果这是真的，也许我就会知道问题出在哪里了！

---

MenuViewController.m

- (void)viewDidLoad {
    NSLog(@"ChemicalViewController launched");
    self.title = @"Adjust Chemicals";
    NSMutableArray *array = [[NSMutableArray alloc] init];

// Chlorine Controller
    AdjustViewController *chlorineAdjustViewController = [[AdjustViewController alloc] initWithNibName:@"AdjustViewController" bundle:nil];
    chlorineAdjustViewController.title = @"FC - Free Chlorine";
    chlorineAdjustViewController.numberOfComponents = 2;
    NSLog(@"Generating chlorine source dictionary");
    NSDictionary *chlorineSourceDictionary = [self generateChlorineDictionary];
    chlorineAdjustViewController.dictionaryOfSources = chlorineSourceDictionary;
    [chlorineSourceDictionary release];
    [array addObject:chlorineAdjustViewController];
    [chlorineAdjustViewController release];

// CYA Controller
    AdjustViewController *cyaAdjustViewController = [[AdjustViewController alloc] initWithNibName:@"AdjustViewController" bundle:nil];
    cyaAdjustViewController.title = @"CYA - Cyanuric Acid";
    cyaAdjustViewController.numberOfComponents = 1;
    NSLog(@"Generating cya source dictionary");
    NSDictionary *cyaSourceDictionary = [self generateCYADictionary];
    cyaAdjustViewController.dictionaryOfSources = cyaSourceDictionary;
    [cyaSourceDictionary release];
    [array addObject:cyaAdjustViewController];
    [cyaAdjustViewController release];

---

内部 AdjustViewController.m

// Present the picker for chlorine selection
- (IBAction)getChemicalSource {
    SourcePickerViewController *sourcePickerViewController = [[SourcePickerViewController alloc] init];
    sourcePickerViewController.delegate = self;
    NSLog(@"getChemicalSource setting numberOfComponents %d", self.numberOfComponents);
    sourcePickerViewController.numberOfComponents = self.numberOfComponents;
    NSLog(@"getChemicalSource sending numberOfComponents %d", sourcePickerViewController.numberOfComponents);
    sourcePickerViewController.dictionaryOfSources = self.dictionaryOfSources;
    [self presentModalViewController:sourcePickerViewController animated:YES];
    [sourcePickerViewController release];
}

#pragma mark -
#pragma mark Picker View Delegate Methods

// Returns the values from the picker if a source was chosen
- (void)sourcePickerViewController:(SourcePickerViewController *)controller 
               didSelectSource:(NSString *)source 
              andConcentration:(NSString *)concentration 
                   andConstant:(float)constant 
                   andIsLiquid:(BOOL)isLiquid {


    sourceField.text = [[NSString alloc] initWithFormat:@"%@, %@", source, concentration];
    [self updateAdvice];
    NSLog(@"Returned source = %@, concentration = %@, sourceConstant = %1.7f, isLiquid = %d", source, concentration, constant, isLiquid);
    [self dismissModalViewControllerAnimated:YES];
}

// Returns from the picker without choosing a new source
- (void)sourcePickerViewController:(SourcePickerViewController *)controller 
               didSelectCancel:(BOOL)didCancel {
    [self updateAdvice];
    NSLog(@"Returned without selecting source");
    [self dismissModalViewControllerAnimated:YES];
}

---

内部 SourceViewController.m

- (void)viewDidLoad {
    NSLog(@"SourcePickerViewController launched");
    NSLog(@"viewDidLoad");
    NSLog(@"Received numberOfComponents %d", self.numberOfComponents);
    self.chemicalSources = dictionaryOfSources;
    NSArray *components = [self.chemicalSources allKeys];
    NSArray *sorted = [components sortedArrayUsingSelector:@selector(compare:)];
    self.sources = sorted; // This array has the chemical sources

    if (self.numberOfComponents = 2) {
        NSString *selectedSource = [self.sources objectAtIndex:0];
        NSArray *chemArray = [self.chemicalSources objectForKey:selectedSource];
        NSMutableArray *concentrationArray = [[NSMutableArray alloc] init];
        int num = [chemArray count];
        for (int i=0; i<num; i++) {
            [concentrationArray addObject:[[chemArray objectAtIndex:i] chemConcentration]];
        }
        self.concentrations = concentrationArray;
    }
    [super viewDidLoad];
}

    #pragma mark -
    #pragma mark Picker Data Source Methods

- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {
    NSLog(@"numberOfComponentsInPickerView, self.numberOfComponents = %d", self.numberOfComponents);
    return self.numberOfComponents;
}

- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {
    NSLog(@"numberOfRowsInComponent, self.numberOfComponents = %d", self.numberOfComponents);
    if (component == kSourceComponent)
        return [self.sources count];
    return [self.concentrations count];
}

#pragma mark Picker Delegate Methods

- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {
    if (component == kSourceComponent)
        return [self.sources objectAtIndex:row];
    return [self.concentrations objectAtIndex:row];
}

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
    NSLog(@"didSelectRow, self.numberOfComponents = %d", self.numberOfComponents);
    if (numberOfComponents = 2) {
        if (component == kSourceComponent) {
            NSString *selectedSource = [self.sources objectAtIndex:row];
            NSArray *chemArray = [self.chemicalSources objectForKey:selectedSource];
            NSMutableArray *concentrationArray = [[NSMutableArray alloc] init];
            int num = [chemArray count];
            for (int i=0; i<num; i++) {
                [concentrationArray addObject:[[chemArray objectAtIndex:i] chemConcentration]];
            }
    self.concentrations = concentrationArray;
    [picker selectRow:0 inComponent:kConcentrationComponent animated:YES];
    [picker reloadComponent:kConcentrationComponent];
    }
}
}

- (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component {
    if (component == kConcentrationComponent)
        return 90;
    return 205;
}

Answer 1

我没有查看你所有的代码；相反，我建议写出 numberOfComponents 的属性，而不是 @synthesize'ing 它们。只需摆脱 @synthesize，然后 make:

 - (int)numberOfComponents {
   return m_numberOfComponents;
}

然后

 - (void)setNumberOfComponents(int aNumberOfComponents) {
   m_numberOfComponents = aNumberOfComponents;
}

，在 setNumberOfComponents 函数中设置一个断点，您应该能够看到它何时被调用，这样您就可以看到发生了什么。我希望这有帮助！