3 单视图控制器中的 UIPicker 视图

Question

我的视图控制器中有 3 个选取器视图选取器1包含2行音频和视频.picker2包含产品类型，如果在选取器1中选择音频，则选取器2应填充（transistor,walkman,ipod），如果在拾取器1中选择视频，则选取器2应填充（tv,screen,monitor），如果在拾取器2中选择了随身听，则拾取器3应填充（sony,philips,jbl）。我对 if 条件感到困惑....

if ([[categoryArray objectAtIndex:row] isEqual:@"Audio"] && [[audioProduct objectAtIndex:row] isEqual:@"walkman"])
{
    NSLog(@"Audio and walkman");
    modelArray=[[NSMutableArray alloc]initWithObjects:@"walkman1",@"walkman2",@"walman3", nil];
        [modelPickerView reloadAllComponents];   
}
else if ([[categoryArray objectAtIndex:row] isEqual:@"Audio"] && [[audioProduct objectAtIndex:row] isEqual:@"mp3"]) {
modelArray=[[NSMutableArray alloc]initWithObjects:@"mp3",@"mp3", @"mp3",@"mp3",nil];
    [modelPickerView reloadAllComponents];
}

Answer 1

您必须有条件地加载选取器 2 和选取器 3，如下所示：

picker1Array=[[NSMutableArray alloc] initWithObjects:@"Audio",@"Video", nil]
if ([[picker1array objectAtIndex:[picker1 selectedRowInComponent:0]] isEqual:@"Audio"])
{
    picker2Array=[[NSMutableArray alloc] initWithObjects:@"transistor",@"walkman",@"ipod", nil];
}
else {
    picker2Array=[[NSMutableArray alloc] initWithObjects:@"tv",@"screen",@"monitor", nil];
}
 [picker2 reloadAllComponents];  
if ([[picker2array objectAtIndex:[picker2 selectedRowInComponent:0]] isEqual:@"walkman"]){
   picker3Array=[[NSMutableArray alloc] initWithObjects:@"sony",@"philips",@"jbl", nil];
} 
[picker3 reloadAllComponents];  

Answer 2

请尝试以下代码。

在 .h 文件中，请声明

NSMutableArray *randCatSel;
    NSMutableArray *randSubCatSel;
    NSMutableArray *randItemSel;
    UIPickerView *packerView;

并在 .m 文件中编写此代码。

- (void)fetchedData{
    randCatSel =[[NSMutableArray alloc] initWithObjects:@"Audio",@"Video", nil];
    packerView=[[UIPickerView alloc] initWithFrame:CGRectMake(0, 280, 320, 200)];
    packerView.delegate=self;
    packerView.dataSource=self;
    packerView.tag=1;
    [self.view addSubview:packerView];
}
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
    return 1;
}
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent: (NSInteger)component
{
    if(pickerView.tag==1)
    {
        return [randCatSel count];
    }
    else if(pickerView.tag==2)
    {
        return [randSubCatSel count];
    }
    else if(pickerView.tag==3)
    {
        return [randItemSel count];
    }
    else
    {
        return 0;
    }
}
-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row   forComponent:(NSInteger)component
{
    if(pickerView.tag==1)
    {
        return [randCatSel objectAtIndex:row];
    }
    else if(pickerView.tag==2)
    {
        return [randSubCatSel objectAtIndex:row];
    }
    else if(pickerView.tag==3)
    {
        return [randItemSel objectAtIndex:row];
    }
    else
    {
        return 0;
    }

}
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
    if(pickerView.tag==1)
    {
        if(randSubCatSel.count>0)
        {
            randSubCatSel=nil;
        }
        if([[randCatSel objectAtIndex:row] isEqualToString:@"Audio"])
        {
                    randSubCatSel=[[NSMutableArray alloc] initWithObjects:@"Transistor",@"walkman",@"ipod", nil];
        }
        else
        {
                    randSubCatSel=[[NSMutableArray alloc] initWithObjects:@"TV",@"Screen",@"Monitor", nil];
        }
        [packerView removeFromSuperview];
        packerView=[[UIPickerView alloc] initWithFrame:CGRectMake(0, 280, 320, 200)];
        packerView.delegate=self;
        packerView.dataSource=self;
        packerView.tag=2;
        [self.view addSubview:packerView];
    }
    else if(pickerView.tag==2)
    {
        //do coding according to randSubCatSel for randItemSel
    }
}

请注意，这是满足您要求的示例代码。 您需要相应地进行更改。我希望这段代码对您有所帮助。