使用KVO模式,设置应用角标数字

 1 #import "AppDelegate.h"
 2 
 3 @interface AppDelegate ()
 4 
 5 @end
 6 
 7 @implementation AppDelegate
 8 
 9 
10 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
11     //注册推送
12     //申请设置角标数字权限
13     [application registerUserNotificationSettings:[UIUserNotificationSettings settingsForTypes:UIUserNotificationTypeBadge categories:nil]];
14     
15     return YES;
16 }
17 //观察者回调方法
18 -(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSString *,id> *)change context:(void *)context
19 {
20     //获取badgeValue的新值
21     NSString *value = change[NSKeyValueChangeNewKey];
22     NSLog(@"%@",value);
23     [UIApplication sharedApplication].applicationIconBadgeNumber = value.integerValue ;
24 }

 1 #import "ViewController.h"
 2 #import "AppDelegate.h"
 3 @interface ViewController ()
 4 
 5 @end
 6 
 7 @implementation ViewController
 8 
 9 - (void)viewDidLoad {
10     [super viewDidLoad];
11     
12     
13     AppDelegate *appDelegate = (AppDelegate *)[UIApplication sharedApplication].delegate;
14     //注册观察者
15     [self addObserver:appDelegate forKeyPath:@"tabBarItem.badgeValue" options:NSKeyValueObservingOptionNew context:nil];
16     //触发观察者
17     self.tabBarItem.badgeValue = @"9";
18     self.tabBarItem.badgeValue = @"123";
19     self.tabBarItem.badgeValue = @"456";
20     //移除观察者
21     [self removeObserver:appDelegate forKeyPath:@"tabBarItem.badgeValue"];
22     
23 }
24 
25 - (void)didReceiveMemoryWarning {
26     [super didReceiveMemoryWarning];
27     // Dispose of any resources that can be recreated.
28 }