Ios 动态设置UIViewController指针内联-目标C

我有一个iOS应用程序，带有for循环，可以创建、设置并向我的视图添加自定义视图控制器。问题是，我需要根据当前循环编号，将

UIViewController

对象动态设置为正确的类。这是我的密码：

// Loop through the data and setup the switches.
    
for (NSUInteger loop = 0; loop < [switchLabels count]; loop++) {
        
    // Create the view controller object.
    UIViewController *screen;
        
    // Create the custom switch view.
        
    if (loop < 3) {
        screen = [[CustomSwitchView alloc] initWithNibName:@"CustomSwitchView" bundle:nil];
    } else {
        screen = [[CustomTripleSwitchView alloc] initWithNibName:@"CustomTripleSwitchView" bundle:nil];
    }
        
    // Create the custom switch view.
    [screen setPassedInType:switchTypes[loop]];
    [screen setDelegate:self];
    [self addChildViewController:screen];
    [screen.view setFrame:CGRectMake((self.view.frame.size.width - 150), ((UILabel *)switchLabels[loop]).frame.origin.y, 144, 72)];
    [scrollTopView addSubview:screen.view];
    [screen didMoveToParentViewController:self];
    [screen setTitles:switchTitles[loop] state:[switchSettings[loop] boolValue]];
}

---

有几种方法可以解决这个问题。对现有代码影响最小的是将方法区分为一般应用于UIViewController的方法和特定于子类的方法。对声明为特定子类的堆栈变量调用子类方法

for (NSUInteger loop = 0; loop < [switchLabels count]; loop++) {

    // Create the view controller object.
    UIViewController *vc;

    // Create the custom switch view.

    if (loop < 3) {
        CustomSwitchView *screen = [[CustomSwitchView alloc] initWithNibName:@"CustomSwitchView" bundle:nil];
        [screen setPassedInType:switchTypes[loop]];
        [screen setDelegate:self];
        [screen setTitles:switchTitles[loop] state:[switchSettings[loop] boolValue]];
        vc = screen;
    } else {
        CustomTripleSwitchView *screen = [[CustomTripleSwitchView alloc] initWithNibName:@"CustomTripleSwitchView" bundle:nil];
        [screen setPassedInType:switchTypes[loop]];
        [screen setDelegate:self];
        [screen setTitles:switchTitles[loop] state:[switchSettings[loop] boolValue]];
        vc = screen;
    }

    // Create the custom switch view.
    [self addChildViewController:vc];
    [vc.view setFrame:CGRectMake((self.view.frame.size.width - 150), ((UILabel *)switchLabels[loop]).frame.origin.y, 144, 72)];
    [scrollTopView addSubview:vc.view];
    [vc didMoveToParentViewController:self];
}

for（整数循环=0；循环<[switchLabels count]；循环++）{
//创建视图控制器对象。
UIViewController*vc；
//创建自定义开关视图。
if（循环<3）{
CustomSwitchView*屏幕=[[CustomSwitchView alloc]initWithNibName:@“CustomSwitchView”捆绑包：nil]；
[screen SetPassedType:switchTypes[loop]]；
[屏幕设置代表：自我]；
[屏幕设置标题：开关标题[循环]状态：[开关设置[循环]布尔值]]；
vc=屏幕；
}否则{
CustomTripleSwitchView*屏幕=[[CustomTripleSwitchView alloc]initWithNibName:@“CustomTripleSwitchView”捆绑包：nil]；
[screen SetPassedType:switchTypes[loop]]；
[屏幕设置代表：自我]；
[屏幕设置标题：开关标题[循环]状态：[开关设置[循环]布尔值]]；
vc=屏幕；
}
//创建自定义开关视图。
[self-addChildViewController:vc]；
[vc.view setFrame:CGRectMake（（self.view.frame.size.width-150），（（UILabel*）switchLabels[loop]）.frame.origin.y，144，72）]；
[scrollTopView添加子视图：vc.view]；
[vc didMoveToParentViewController:self]；
}

---

如果我们在项目中遇到这个问题，这是一个不错的解决方案。当你看到这类事情激增时，是时候开始思考：（a）我应该在每个类上定义一个协议（正如一位评论员恰当地建议的那样），还是（b）这些子类真的相互关联，就像

CustomTripleSwitchView

实际上是

CustomSwitchView

？

的一个子类，如果它们共享您正在使用的一些常用方法，那么您应该声明它们都符合的协议，该协议需要这些方法。然后可以将局部变量声明为

UIViewController*

为什么不在调用实际方法之前尝试使用respondsToSelector？

for (NSUInteger loop = 0; loop < [switchLabels count]; loop++) {

    // Create the view controller object.
    UIViewController *vc;

    // Create the custom switch view.

    if (loop < 3) {
        CustomSwitchView *screen = [[CustomSwitchView alloc] initWithNibName:@"CustomSwitchView" bundle:nil];
        [screen setPassedInType:switchTypes[loop]];
        [screen setDelegate:self];
        [screen setTitles:switchTitles[loop] state:[switchSettings[loop] boolValue]];
        vc = screen;
    } else {
        CustomTripleSwitchView *screen = [[CustomTripleSwitchView alloc] initWithNibName:@"CustomTripleSwitchView" bundle:nil];
        [screen setPassedInType:switchTypes[loop]];
        [screen setDelegate:self];
        [screen setTitles:switchTitles[loop] state:[switchSettings[loop] boolValue]];
        vc = screen;
    }

    // Create the custom switch view.
    [self addChildViewController:vc];
    [vc.view setFrame:CGRectMake((self.view.frame.size.width - 150), ((UILabel *)switchLabels[loop]).frame.origin.y, 144, 72)];
    [scrollTopView addSubview:vc.view];
    [vc didMoveToParentViewController:self];
}