OC-循环push控制器 限制其出现的数量

原理:

主要是对UIViewController进行添加limitNumber属性,在set方法中进行重新self.navigationController.childViewControllers的重新排序

使用方法 :

// 只需要在当前控制器中设置限制数量即可
- (void)viewDidLoad {
    [super viewDidLoad];
    self.limitNumber = 2;
}

打印输出

也可以这样:

#import "OneViewController.h"
#import "UIViewController+HWCategory.h"

@interface OneViewController ()

@end

@implementation OneViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.limitNumber = 1;
}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    OneViewController *vc = [OneViewController new];
    [self.navigationController pushViewController:vc animated:YES];
}

@end

自己push自己

代码

.h文件

#import <UIKit/UIKit.h>

NS_ASSUME_NONNULL_BEGIN

@interface UIViewController (HWCategory)
/** 运行push出现的限制数量 */
@property(nonatomic, assign) NSUInteger limitNumber;

@end

NS_ASSUME_NONNULL_END

.m文件

#import "UIViewController+HWCategory.h"
#import <objc/runtime.h>

static NSString *const hw_pushlimitNumberKey = @"hw_pushlimitNumberKey";

@implementation UIViewController (HWCategory)

- (void)setLimitNumber:(NSUInteger)limitNumber {
    NSString *number = [NSString stringWithFormat:@"%ld", limitNumber];
    objc_setAssociatedObject(self, (__bridge const void * _Nonnull)(hw_pushlimitNumberKey), number, OBJC_ASSOCIATION_ASSIGN);
    [self controllerSort];
}
- (NSUInteger)limitNumber {
    NSString *maxNumber = objc_getAssociatedObject(self, (__bridge const void * _Nonnull)(hw_pushlimitNumberKey));
    return [maxNumber integerValue];
}

- (void)controllerSort {
    NSUInteger limitNum = self.limitNumber;
    NSArray *vcs = self.navigationController.childViewControllers;
    if (limitNum < 1) {return;}
    if (vcs.count <= limitNum) {return;}
    NSMutableArray *newvcs = [vcs mutableCopy];
    NSMutableArray *indexs = [NSMutableArray array]; // 记录存在角标
    for(int i = 0; i < vcs.count; i++){
        UIViewController *vc = vcs[i];
        if ([vc isKindOfClass:[self class]]) {
            [indexs addObject:@(i)];
        }
    }
    if (indexs.count > limitNum) { // 如果存在数量大于限制的 需要进行排序
        for(int i = 0; i < indexs.count-limitNum; i++){ // 移除最前面的
            NSInteger index = [indexs[i] integerValue];
            [newvcs removeObjectAtIndex:index];
        }
        NSLog(@"正常\n:%@\n", vcs);
        NSLog(@"排序后\n:%@\n", newvcs);
        [self.navigationController setViewControllers:newvcs animated:YES];
    }
}

@end

Dome