@interface ViewController ()
{
 NSProgress * progress;
}
@end

@implementation ViewController

- (void)viewDidLoad {
 [super viewDidLoad];
 // Do any additional setup after loading the view, typically from a nib.
 //這個方法將創(chuàng)建任務(wù)進度管理對象 UnitCount是一個基于UI上的完整任務(wù)的單元數(shù)
 progress = [NSProgress progressWithTotalUnitCount:10];
 NSTimer * timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(task) userInfo:nil repeats:YES];
 //對任務(wù)進度對象的完成比例進行監(jiān)聽
 [progress addObserver:self forKeyPath:@"fractionCompleted" options:NSKeyValueObservingOptionNew context:nil];
}
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context

{
 NSLog(@"進度= %f",progress.fractionCompleted);
}
-(void)task{
 //完成任務(wù)單元數(shù)+1
 
 if (progress.completedUnitCount<progress.totalUnitCount) {
  progress.completedUnitCount +=1;
 }
 
}

//顯示完后比例 如：10% completed
@property (null_resettable, copy) NSString *localizedDescription;
//完成數(shù)量 如：1 of 10
@property (null_resettable, copy) NSString *localizedAdditionalDescription;

- (void)viewDidLoad {
 [super viewDidLoad];
 // Do any additional setup after loading the view, typically from a nib.
 //這個方法將創(chuàng)建任務(wù)進度管理對象 UnitCount是一個基于UI上的完整任務(wù)的單元數(shù)
 progress = [NSProgress progressWithTotalUnitCount:10];
 //對任務(wù)進度對象的完成比例進行監(jiān)聽
 [progress addObserver:self forKeyPath:@"fractionCompleted" options:NSKeyValueObservingOptionNew context:nil];
 //向下分支出一個子任務(wù) 子任務(wù)進度總數(shù)為5個單元 即當(dāng)子任務(wù)完成時 父progerss對象進度走5個單元
 [progress becomeCurrentWithPendingUnitCount:5];
 [self subTaskOne];
 [progress resignCurrent];
 //向下分出第2個子任務(wù)
 [progress becomeCurrentWithPendingUnitCount:5];
 [self subTaskOne];
 [progress resignCurrent];
}

-(void)subTaskOne{
 //子任務(wù)總共有10個單元
 NSProgress * sub =[NSProgress progressWithTotalUnitCount:10];
 int i=0;
 while (i<10) {
  i++;
  sub.completedUnitCount++;
 }
}

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context

{
 NSLog(@"= %@",progress.localizedAdditionalDescription);
}

- (void)viewDidLoad {
 [super viewDidLoad];
 // Do any additional setup after loading the view, typically from a nib.
 //這個方法將創(chuàng)建任務(wù)進度管理對象 UnitCount是一個基于UI上的完整任務(wù)的單元數(shù)
 progress = [NSProgress progressWithTotalUnitCount:10];
 //對任務(wù)進度對象的完成比例進行監(jiān)聽
 [progress addObserver:self forKeyPath:@"fractionCompleted" options:NSKeyValueObservingOptionNew context:nil];
 //創(chuàng)建子節(jié)點
 NSProgress * sub = [NSProgress progressWithTotalUnitCount:10 parent:progress pendingUnitCount:5];
 NSProgress * sub2 = [NSProgress progressWithTotalUnitCount:10 parent:progress pendingUnitCount:5];
 for (int i=0; i<10; i++) {
  sub.completedUnitCount ++;
  sub2.completedUnitCount ++;
 }
}

//獲取當(dāng)前線程的進度管理對象根節(jié)點
//注意：當(dāng)有NSProgress對象調(diào)用了becomeCurrentWithPendingUnitCount:方法后，這個方法才能獲取到
+ (nullable NSProgress *)currentProgress;
//創(chuàng)建一個NSProgress對象，需要傳入進度的單元數(shù)量
+ (NSProgress *)progressWithTotalUnitCount:(int64_t)unitCount;
//和上一個方法功能相似 iOS9之后的新方法
+ (NSProgress *)discreteProgressWithTotalUnitCount:(int64_t)unitCount;
//iOS9之后的新方法 創(chuàng)建某個進度指示器節(jié)點的子節(jié)點
+ (NSProgress *)progressWithTotalUnitCount:(int64_t)unitCount parent:(NSProgress *)parent pendingUnitCount:(int64_t)portionOfParentTotalUnitCount;
//NSProgress實例的初始化方法 自父節(jié)點參數(shù)可以為nil
- (instancetype)initWithParent:(nullable NSProgress *)parentProgressOrNil userInfo:(nullable NSDictionary *)userInfoOrNil;
//注冊為當(dāng)前線程根節(jié)點
- (void)becomeCurrentWithPendingUnitCount:(int64_t)unitCount;
//取消注冊 與注冊方法必須同步出現(xiàn)
- (void)resignCurrent;
//iOS9新方法 向一個節(jié)點中添加一個子節(jié)點
- (void)addChild:(NSProgress *)child withPendingUnitCount:(int64_t)inUnitCount;
//進度單元總數(shù)
@property int64_t totalUnitCount;
//已完成的進度單元數(shù)
@property int64_t completedUnitCount;
//是否可取消
@property (getter=isCancellable) BOOL cancellable;
//是否可暫停
@property (getter=isPausable) BOOL pausable;
//進度比例 0-1之間
@property (readonly) double fractionCompleted;
//取消
- (void)cancel;
//暫停
- (void)pause;
//恢復(fù)
- (void)resume

//設(shè)置剩余時間 會影響localizedAdditionalDescription的值
/*
例如：0 of 10 — About 10 seconds remaining
*/
[progress setUserInfoObject:@10 forKey:NSProgressEstimatedTimeRemainingKey];
//設(shè)置完成速度信息 會影響localizedAdditionalDescription的值
/*
例如：Zero KB of 10 bytes (15 bytes/sec)
*/
[progress setUserInfoObject:@15 forKey:NSProgressThroughputKey];
/*
下面這些鍵值的生效 必須將NSProgress對象的kind屬性設(shè)置為 NSProgressKindFile
NSProgressFileOperationKindKey鍵對應(yīng)的是提示文字類型 會影響localizedDescription的值
NSProgressFileOperationKindKey可選的對應(yīng)值如下：
NSProgressFileOperationKindDownloading： 顯示Downloading files…
NSProgressFileOperationKindDecompressingAfterDownloading： 顯示Decompressing files…
NSProgressFileOperationKindReceiving： 顯示Receiving files…
NSProgressFileOperationKindCopying： 顯示Copying files…
*/
 [progress setUserInfoObject:NSProgressFileOperationKindDownloading forKey:NSProgressFileOperationKindKey];
/*
NSProgressFileTotalCountKey鍵設(shè)置顯示的文件總數(shù) 
例如：Copying 100 files…
*/
 [progress setUserInfoObject:@100 forKey:NSProgressFileTotalCountKey];
//設(shè)置已完成的數(shù)量
[progress setUserInfoObject:@1 forKey:NSProgressFileCompletedCountKey];