如何在顶部状态栏中显示加载指示器

我注意到一些应用程序(如Safari和Mail)在访问网络时在状态栏(手机最顶部的栏)中显示加载指示符.有没有办法在SDK应用程序中做同样的事情,或者这只是Apple的事情？

1> Stephen Darl..：

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它在UIApplication中:

[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;

对于swift:

[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;

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@rustyshelf,它显示在较新的模拟器中.

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`[[UIApplication sharedApplication] setNetworkActivityIndi​​catorVisible:YES];`//作为一个班轮

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活动指示器不会显示在iPhone X的状态栏中

2> Michael Wate..：

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我发现以下宏非常有用!

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

所以你可以在你的应用程序中调用ShowNetworkActivityIndicator();或调用HideNetworkActivityIndicator();(只要包含标题!).

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为什么不在UIApplication上定义一个类别？看起来比#define更好(也更可调试).

3> Resh32..：

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我写了一个单例,通过保持对正在发生的事情的计数器来解决多个连接的问题(以避免在连接返回但另一个仍处于活动状态时删除状态):

头文件:

#import 

@interface RMActivityIndicator : NSObject

-(void)increaseActivity;
-(void)decreaseActivity;
-(void)noActivity;

+(RMActivityIndicator *)sharedManager;

@end

和实施:

#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];
    }

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谢谢@Schrockwell,我通过使用synchronized块进一步改进了它 - 我看到了一个竞争条件,活动没有正确减少.

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如何做简单事情的好例子很难)

4> asish..：

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一行代码:

[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;

5> 小智..：

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完成网络呼叫后,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.

在AppDelegate课程中进行以下更改:

进口 AFNetworking/AFNetworkActivityIndicatorManager.h

把它放进去 didFinishLaunchingWithOptions:

[[AFNetworkActivityIndicatorManager sharedManager] setEnabled:YES]