如何在顶部状态栏显示加载指示器

我注意到，Safari和Mail等应用在访问networking时，会在状态栏（电话顶部的栏）中显示一个加载指示符。 有没有办法在SDK应用程序中做同样的事情呢，还是只有苹果？

Answer 1

它在UIApplication中：

[UIApplication sharedApplication].networkActivityIndicatorVisible = YES; 

为迅速：

 UIApplication.shared.isNetworkActivityIndicatorVisible = true 

Answer 2

我发现下面的macros很有用！

 #define ShowNetworkActivityIndicator() [UIApplication sharedApplication].networkActivityIndicatorVisible = YES #define HideNetworkActivityIndicator() [UIApplication sharedApplication].networkActivityIndicatorVisible = NO 

所以你可以调用ShowNetworkActivityIndicator(); 或HideNetworkActivityIndicator(); 从你的应用程序（只要标题是包括当然！）。

Answer 3

我写了一个单例解决多个连接的问题，通过保持一个正在发生的事情的计数器（避免在连接返回时移除状态，但是另一个仍然处于活动状态）：

头文件：

 #import <Foundation/Foundation.h> @interface RMActivityIndicator : NSObject -(void)increaseActivity; -(void)decreaseActivity; -(void)noActivity; +(RMActivityIndicator *)sharedManager; @end 

和执行：

 #import "RMActivityIndicator.h" @interface RMActivityIndicator () @property(nonatomic,assign) unsigned int activityCounter; @end @implementation RMActivityIndicator - (id)init { self = [super init]; if (self) { self.activityCounter = 0; } return self; } -(void)increaseActivity{ @synchronized(self) { self.activityCounter++; } [self updateActivity]; } -(void)decreaseActivity{ @synchronized(self) { if (self.activityCounter>0) self.activityCounter--; } [self updateActivity]; } -(void)noActivity{ self.activityCounter = 0; [self updateActivity]; } -(void)updateActivity{ UIApplication* app = [UIApplication sharedApplication]; app.networkActivityIndicatorVisible = (self.activityCounter>0); } #pragma mark - #pragma mark Singleton instance +(RMActivityIndicator *)sharedManager { static dispatch_once_t pred; static RMActivityIndicator *shared = nil; dispatch_once(&pred, ^{ shared = [[RMActivityIndicator alloc] init]; }); return shared; } @end 

例：

  [[RMActivityIndicator sharedManager]increaseActivity]; [NSURLConnection sendAsynchronousRequest:urlRequest queue:self.networkReceiveProcessQueue completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) { [[RMActivityIndicator sharedManager]decreaseActivity]; } 

Answer 4

一个单行代码来做到这一点：

 [UIApplication sharedApplication].networkActivityIndicatorVisible = YES; 

Answer 5

一旦networking通话完成，您还需要注意隐藏活动指示器。

如果你使用AFNetworking ，那么你不需要做太多的事情。

在AppDelegate类中进行以下更改：

1. 导入AFNetworking/AFNetworkActivityIndicatorManager.h

2. 把这个放在didFinishLaunchingWithOptions:

[[AFNetworkActivityIndicatorManager sharedManager] setEnabled:YES]

Answer 6

确保您在主线程上运行它也可能是有帮助的，因为它与UI相关。

 dispatch_async(dispatch_get_main_queue(), ^{ [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES]; });