使用开源库 MBProgressHUD 等待指示器

source https://github.com/jdg/MBProgressHUD

MBProgressHUD is an iOS drop-in class that displays a translucent HUD with an indicator and/or labels while work is being done in a background thread. The HUD is meant as a replacement for the undocumented, private UIKit UIProgressHUD with some additional features.

MBProgressHUD是一个iOS中继承的子类,当在后台线程中执行一些任务时,将展示出一个半透明的指示器或者标签.毫无疑问,HUD是用来替换苹果自身使用的私有API的,但同时该HUD会提供更多地特性.

 

以下是本人使用该开源库的心得分享以及简单地使用教程

1. 将MBProgressHUD.h MBProgressHUD.m 拖入到工程项目当中,MBProgressHUD本身支持ARC与非ARC

看其源码,其控制ARC与非ARC的宏值得学习
#if __has_feature(objc_instancetype)
    #define MB_INSTANCETYPE instancetype
#else
    #define MB_INSTANCETYPE id
#endif

#if __has_feature(objc_arc)
    #define MB_STRONG strong
#else
    #define MB_STRONG retain
#endif

#if __has_feature(objc_arc_weak)
    #define MB_WEAK weak
#elif __has_feature(objc_arc)
    #define MB_WEAK unsafe_unretained
#else
    #define MB_WEAK assign
#endif

#if __has_feature(objc_arc)
    #define MB_AUTORELEASE(exp) exp
    #define MB_RELEASE(exp) exp
    #define MB_RETAIN(exp) exp
#else
    #define MB_AUTORELEASE(exp) [exp autorelease]
    #define MB_RELEASE(exp) [exp release]
    #define MB_RETAIN(exp) [exp retain]
#endif

2. 初始化以及简单地使用心得

我用同步网络请求来模拟阻塞操作,请将以下两个文件添加进工程项目中

YXSTHTTPRequest.h

#import <UIKit/UIKit.h>



@interface YXSTHTTPRequest : NSObject



/**

 同步网络请求

 

 这是用来进行同步网络请求的,该网络请求忽略本地缓存,使用此同步网络请求需要配合线程使用,否则会阻塞主线程

 

 @param url 网络地址字符串

 @param timeOut 超时的时间(当把请求设置成POST时,请求时间会被设置成240秒的默认值,自己设置的低于240秒的无效)

 @param setRequest 一个用于配置 NSMutableURLRequest 的 block

 @param result 当同步请求有效时,接收数据,或者出错时接收error block

 

 @return none

 */

+ (void)syncConnectionWithURL:(NSString *)url timeOut:(NSTimeInterval)time

                   setRequest:(void (^)(NSMutableURLRequest *request))setRequest

                       result:(void (^)(NSData *data, NSError *error))result;



@end

YXSTHTTPRequest.m

#import "YXSTHTTPRequest.h"



@implementation RootViewController



+ (void)syncConnectionWithURL:(NSString *)url timeOut:(NSTimeInterval)time

                   setRequest:(void (^)(NSMutableURLRequest *request))setRequest

                       result:(void (^)(NSData *data, NSError *error))result

{

    //创建一个网络请求

    //NSURLRequestReloadIgnoringLocalCacheData(忽略本地缓存)

    NSMutableURLRequest *request = [NSMutableURLRequest

                                    requestWithURL:[NSURL URLWithString:url]

                                    cachePolicy:NSURLRequestReloadIgnoringLocalCacheData

                                    timeoutInterval:time];

    

    //配置request

    setRequest(request);

    

    //开始同步链接

    //The downloaded data for the URL request. Returns nil if a connection could not be created or if the download fails.

    NSError *connectionError = nil;

    NSData *data = [NSURLConnection sendSynchronousRequest:request

                                         returningResponse:nil

                                                     error:&connectionError];

    

    result(data, connectionError);

}



@end

几个关于线程的宏定义

// 系统子线程池(并发执行)

#define SYS_CONCURRENT_QUEUE_H  dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0)

#define SYS_CONCURRENT_QUEUE_D  dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)

#define SYS_CONCURRENT_QUEUE_L  dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_LOW, 0)

#define SYS_CONCURRENT_QUEUE_B  dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0)



// 系统主线程池(序列执行)

#define SYS_SERIAL_QUEUE      dispatch_get_main_queue()

#define SYS_UI_QUEUE          dispatch_get_main_queue()

初始化以及使用的步骤

    // 初始化 MBProgressHUD 对象

    MBProgressHUD *hud = [[MBProgressHUD alloc] initWithWindow:self.view.window];

    

    // 添加进当前视图中

    [self.view addSubview:hud];

    

    // 显示动画

    [hud showAnimated:YES

  whileExecutingBlock:^{

      // 阻塞的代码

      

      // 请在此处添加需要等待操作的代码

    }

              onQueue:SYS_SERIAL_QUEUE

      completionBlock:^{



          // 结束后从父视图中移除

          [hud removeFromSuperview];

          [hud release];

    }];

查看其源码(如下所示),其whileExecutingBlock执行在queue中,也就是说需要自己给queue设定参数,要么是序列化queue,要么是并发queue,注意

- (void)showAnimated:(BOOL)animated whileExecutingBlock:(dispatch_block_t)block onQueue:(dispatch_queue_t)queue

     completionBlock:(MBProgressHUDCompletionBlock)completion {

    self.taskInProgress = YES;

    self.completionBlock = completion;

    dispatch_async(queue, ^(void) {

        block();

        dispatch_async(dispatch_get_main_queue(), ^(void) {

            [self cleanUp];

        });

    });

  [self show:animated];

}

一般情况下,我们需要使用序列queue(dispatch_get_main_queue()),以下是一个完整地使用示例(请将代码放入一个button事件中)

    // 初始化 MBProgressHUD 对象

    MBProgressHUD *hud = [[MBProgressHUD alloc] initWithWindow:self.view.window];

    

    // 添加进当前视图中

    [self.view addSubview:hud];

    

    // 显示动画

    [hud showAnimated:YES

  whileExecutingBlock:^{

      // 阻塞操作

      NSString *urlStr = @"http://wallpapers.wallbase.cc/rozne/wallpaper-2903212.jpg";

      [YXSTHTTPRequest syncConnectionWithURL:urlStr

                                     timeOut:20

                                  setRequest:^(NSMutableURLRequest *request) {

                                      

                                  }

                                      result:^(NSData *data, NSError *error) {

                                          if (error == nil) {

                                              NSLog(@"完成");

                                          }

                                      }];



    }

              onQueue:SYS_SERIAL_QUEUE

      completionBlock:^{



          // 结束后从父视图中移除

          [hud removeFromSuperview];

          [hud release];

    }];

显示下载进度条(无法使用block的方式,需要设置代理)

    // 初始化 MBProgressHUD 对象

    hud = [[MBProgressHUD alloc] initWithWindow:self.view.window];

    

    // 添加进父视图

    [self.view addSubview:hud];

    

    // 下载进度模式

    hud.mode = MBProgressHUDModeDeterminate;

    

    // 标签

    hud.labelText = @"正在下载";

    

    // 协议

    hud.delegate = self;

    

    // 执行

    [hud showWhileExecuting:@selector(myProgress)

                   onTarget:self

                 withObject:nil

                   animated:YES];





- (void)myProgress

{

    // 进度条显示

    

    float progress = 0.0f;

    while (progress < 1.0f) {

        progress += 0.01f;

        hud.progress = progress;

        usleep(50000);

    }

}





- (void)hudWasHidden:(MBProgressHUD *)hud

{

    // Remove HUD from screen when the HUD was hidded

    [hud removeFromSuperview];

    [hud release];

    hud = nil;

}

以下3个枚举值反应了3中下载进度的图形显示,均属于下载进度模式

MBProgressHUDModeDeterminate

MBProgressHUDModeDeterminateHorizontalBar

MBProgressHUDModeAnnularDeterminate

接下来是比较复杂的混合模式,混合了几个阶段,非常实用

@interface RootViewController ()<MBProgressHUDDelegate>



{

    MBProgressHUD *HUD;

}



@end





- (void)buttonsEvent:(UIButton *)button

{

    HUD = [[MBProgressHUD alloc] initWithView:self.view];

    [self.view addSubview:HUD];

    

    HUD.delegate = self;

    HUD.labelText = @"连接网络...";

    HUD.minSize = CGSizeMake(135.f, 135.f);

    

    [HUD showWhileExecuting:@selector(myMixedTask)

                   onTarget:self

                 withObject:nil

                   animated:YES];

}





- (void)myMixedTask

{

    // 阻塞操作(请将阻塞操作代替sleep函数)

    sleep(2);

    

    // 切换到下载模式(请将阻塞操作代替usleep函数)

    HUD.mode = MBProgressHUDModeDeterminate;

    HUD.labelText = @"下载进度";

    float progress = 0.0f;

    while (progress < 1.0f)

    {

        progress += 0.01f;

        HUD.progress = progress;

        usleep(50000);

    }

    

    // 切换到默认显示的模式(请将阻塞操作代替sleep函数)

    HUD.mode = MBProgressHUDModeIndeterminate;

    HUD.labelText = @"清理完毕";

    sleep(2);

    

    // 切换到自定义图片的模式,在主线程中显示图片(说明此方法执行在子线程中)

    __block UIImageView *imageView;

    dispatch_sync(SYS_UI_QUEUE, ^{

        UIImage *image = [UIImage imageNamed:@"37x-Checkmark.png"];

        imageView = [[UIImageView alloc] initWithImage:image];

    });

    HUD.customView = [imageView autorelease];

    HUD.mode = MBProgressHUDModeCustomView;

    HUD.labelText = @"完成";

    

    // 延时2秒后消失

    sleep(2);

}



- (void)hudWasHidden:(MBProgressHUD *)hud

{

    // Remove HUD from screen when the HUD was hidded

    [hud removeFromSuperview];

    [hud release];

    hud = nil;

}

总结:

1. 涉及到下载进度的时候,必须使用代理来实现进度条的显示

2. 这是用来指示阻塞操作的指示器

3. 混合模式使用非常方便

4. 可以使用自定义View