保存视图中的两个 PickerView 问题？

Question

我试图在同一个视图中有 2 个选择器视图。除了两件事之外，它是有效的。如果一个选择器视图的行数多于另一个选择器视图的行数，则当从具有更多项目的选择器视图中选择项目时，应用程序会崩溃。另外，我为 pickerviews 创建了一个 NSLog，控制台显示我正在一次选择两个项目，而实际上我只处理一个 pickerview。我知道这听起来有点令人困惑，但我包含了所有代码。先感谢您。

list 和 list2 是 NSMutableArrays

列表有 4 项 list2 有 5 项

存在错误：

* 由于未捕获的异常“NSRangeException”而终止应用程序，原因：“* -[NSCFArray objectAtIndex:]：索引 (4) 超出界限 (4)”

-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)thePickerView{
    if([thePickerView isEqual:pickerView1 ]){       
        return 1;
    }
    else if([thePickerView isEqual:pickerView2]){ 

        return  1;
    }

    else{
        return 0;
    }
}

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

    if([thePickerView isEqual:pickerView1 ]){ 
        return [list count];
    }
    else if([thePickerView isEqual:pickerView2]){       
        return [list2 count];
    }

    else{
        return 0;
    }
}

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

    if([thePickerView isEqual:pickerView1 ]){ 
        return [list objectAtIndex:row];
    }
    else if([thePickerView isEqual:pickerView2]){       
        return [list2 objectAtIndex:row];
    }

    else{
        return 0;
    }

} 

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

    NSLog(@"Selected item %@. Index of selected item:%i", [list objectAtIndex:row], row);
    NSLog(@"Selected item %@. Index of selected item:%i", [list2 objectAtIndex:row], row);
    NSLog(@"Selected item %@. Index of selected item:%i", [list3 objectAtIndex:row], row);

if([thePickerView isEqual:pickerView1 ]){
//Do Something
}
else if([thePickerView isEqual:pickerView2 ]){
//Do Something
}
else if([thePickerView isEqual:pickerView3 ]){
//Do Something
}
}

Answer 1

您的问题在这里：

NSLog(@"Selected item %@. Index of selected item:%i", [list objectAtIndex:row], row);
NSLog(@"Selected item %@. Index of selected item:%i", [list2 objectAtIndex:row], row);
NSLog(@"Selected item %@. Index of selected item:%i", [list3 objectAtIndex:row], row);

发生的情况是上面的列表之一被发送一条消息以返回超出其范围的对象。在向日志发送消息之前，您应该检查调用来自哪个选择器：

if([thePickerView isEqual:pickerView1 ]){
  NSLog(@"Selected item %@. Index of selected item:%i", [list objectAtIndex:row], row);
  //Do Something
}
else if([thePickerView isEqual:pickerView2 ]){
  NSLog(@"Selected item %@. Index of selected item:%i", [list2 objectAtIndex:row], row);
  //Do Something
}
else if([thePickerView isEqual:pickerView3 ]){
  NSLog(@"Selected item %@. Index of selected item:%i", [list3 objectAtIndex:row], row);
  //Do Something
}