Question

所以，我有滑块添加UITextFields，但是当选择小于之前的Slider Value时，它不会更新/减去UITextField。是[self.view addSubview：textField];需要在for循环之外吗？提前谢谢。

- (IBAction) sliderValueChanged:(UISlider *)sender {
float senderValue = [sender value];
int roundedValue = senderValue * 1;
ingredientLabel.text = [NSString stringWithFormat:@"%d", roundedValue];
int moveYBy = 35;
int baseY = 140;
for(int y = 0; y < roundedValue; y++){
    UITextField *textField = [[UITextField alloc] initWithFrame:CGRectMake(20, baseY, 227, 31)];
    textField.text = [NSString stringWithFormat:@"%d", roundedValue];
    textField.borderStyle = UITextBorderStyleRoundedRect;
    baseY = baseY + moveYBy;
    [self.view addSubview:textField];
    [textField release];
    NSLog(@"Adding %d fields!", roundedValue);
}
NSLog(@"%d", roundedValue);
}

Answer 1

每次滑块值更改时，您都会创建N个文本字段（其中n是舍入值）。

相反，您应该将NSMutableArray设为iVar并存储所有文本字段，当roundedValue大于该数组中的文本字段数时，我们会添加更多。如果它更小，我们删除一些。

（我正在使用一个名为textFieldsArray的iVar，我也改变了为数组计算y的方式）

- (IBAction) sliderValueChanged:(UISlider *)sender {
    float senderValue = [sender value];
    int roundedValue = senderValue * 1;
    ingredientLabel.text = [NSString stringWithFormat:@"%d", roundedValue];
    for(int y = 0; y < roundedValue; y++){
        if(y > [textFieldsArray count]){
            UITextField *textField = [[UITextField alloc] initWithFrame:CGRectMake(20, 140 + 35 * y, 227, 31)];
            textField.text = [NSString stringWithFormat:@"%d", roundedValue];
            textField.borderStyle = UITextBorderStyleRoundedRect;
            [self.view addSubview:textField];
            [textFieldsArray addObject:textField];
            [textField release];
            NSLog(@"Adding %d fields!", roundedValue);
        }
    }
    while([textFieldsArray count] > roundedValue){
        UITextField *textField = [textFieldsArray lastObject];
        [textField removeFromSuperview];
        [textFieldsArray removeLastObject];
    }
    NSLog(@"%d", roundedValue);
}

uislider添加uitextfield但不更新

1 个答案: