[摘要]本文是對(20160601)開源第三方學習之SVProgressHUD的講解，對學習IOS蘋果軟件開發有所幫助,與大家分享。

SVProgressHUD相信在很多項目中都有運用，運用於彈出窗提示效果；

地址：https://github.com/SVProgressHUD/SVProgressHUD

一：插件的運用

1.1 首先SVProgressHUD是一個單例（[SVProgressHUD method]），所以可以使用起來也相當方便跟簡單，可以寫在任意位置；但必須在主線程中進行顯示，或則會報閃退；也可以用於顯示一個提示信息。所述顯示時間取決於給定的字符串的長度（ 0.5至5秒）

其中幾種展現：
+ (void)showInfoWithStatus:(NSString *)string;
+ (void)showSuccessWithStatus:(NSString*)string;
+ (void)showErrorWithStatus:(NSString *)string;
+ (void)showImage:(UIImage*)image status:(NSString*)string;
+ (void)showProgress:(float)progress status:(NSString*)status;

簡單HUD銷毀：
+ (void)dismiss;
+ (void)dismissWithDelay:(NSTimeInterval)delay;
+ (void)dismissWithCompletion:(SVProgressHUDDismissCompletion)completion;
+ (void)dismissWithDelay:(NSTimeInterval)delay completion:(SVProgressHUDDismissCompletion)completion;

批量HUD銷毀
+ (void)popActivity;

1.2 SVProgressHUD可通過下列方法進行個性化定制:

+ (void)setDefaultStyle:(SVProgressHUDStyle)style;                  // 默認是SVProgressHUDStyleLight
+ (void)setDefaultMaskType:(SVProgressHUDMaskType)maskType;         // 默認是SVProgressHUDMaskTypeNone
+ (void)setDefaultAnimationType:(SVProgressHUDAnimationType)type;   // 默認是 SVProgressHUDAnimationTypeFlat
+ (void)setRingThickness:(CGFloat)width;                            // 默認是 2 pt
+ (void)setCornerRadius:(CGFloat)cornerRadius;                      // 默認是 14 pt
+ (void)setFont:(UIFont*)font;                                      // 默認是 [UIFont preferredFontForTextStyle:UIFontTextStyleSubheadline]
+ (void)setForegroundColor:(UIColor*)color;                         // 默認是 [UIColor blackColor], 僅對 SVProgressHUDStyleCustom 有效
+ (void)setBackgroundColor:(UIColor*)color;                         // 默認是 [UIColor whiteColor], 僅對 SVProgressHUDStyleCustom 有效
+ (void)setInfoImage:(UIImage*)image;                               //默認是bundle文件夾中的提示圖片.
+ (void)setSuccessImage:(UIImage*)image;                            // 默認是bundle文件夾中的成功圖片.
+ (void)setErrorImage:(UIImage*)image;                              // 默認是bundle文件夾中的錯誤圖片.
+ (void)setViewForExtension:(UIView*)view;                          // 默認是nil,僅當設置了 #define SV_APP_EXTENSIONS 時有效.

所以我們可以對於SVProgressHUD做一些調整，比如圖標跟文字的顯示，背景色等；已經是相當的靈活；

1.3 SVProgressHUD帶的四個通知，通過NSNotificationCenter 注冊4份通知,以響應正在顯示/消失:

SVProgressHUDWillAppearNotification 提示框即將出現

SVProgressHUDDidAppearNotification 提示框已經出現

SVProgressHUDWillDisappearNotification 提示框即將消失

SVProgressHUDDidDisappearNotification 提示框已經消失

每個通知傳遞一個userInfo字典,字典中包含HUD的狀態字符串（如果有的話） ，可通過SVProgressHUDStatusUserInfoKey作為鍵來獲取。

SVProgressHUD還發送通知:

SVProgressHUDDidReceiveTouchEventNotification當用戶觸摸整體屏幕上 和

' SVProgressHUDDidTouchDownInsideNotification當用戶直接在HUD接觸。這兩個通知沒有 userInfo參數，但包含了有關的觸摸的UIEvent` 參數.

實例：

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(handleNotification:)
                                                 name:SVProgressHUDWillAppearNotification
                                               object:nil];
    
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(handleNotification:)
                                                 name:SVProgressHUDDidAppearNotification
                                               object:nil];
    
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(handleNotification:)
                                                 name:SVProgressHUDWillDisappearNotification
                                               object:nil];
    
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(handleNotification:)
                                                 name:SVProgressHUDDidDisappearNotification
                                               object:nil];
}

- (void)handleNotification:(NSNotification *)notification {
    NSLog(@"Notification recieved: %@", notification.name);
    NSLog(@"Status user info key: %@", notification.userInfo[SVProgressHUDStatusUserInfoKey]);
}

輸出的內容為，其中Useful Information為提示的文本內容：

SVProgressHUD[793:34162] Notification recieved: SVProgressHUDWillAppearNotification
2016-06-09 21:00:13.285 SVProgressHUD[793:34162] Status user info key: Useful Information.

1.4 相關屬性介紹

1.4.1 SVProgressHUDAnimationType 動作類型

[SVProgressHUD setDefaultAnimationType:SVProgressHUDAnimationTypeFlat]; 圓圈的轉動動作
[SVProgressHUD setDefaultAnimationType:SVProgressHUDAnimationTypeNative]; 菊花型的轉動動作

1.4.2 SVProgressHUDMaskType 彈出窗後面的背景效果類型：

SVProgressHUDMaskTypeNone :當提示顯示的時間，用戶仍然可以做其他操作，比如View 上面的輸入等
SVProgressHUDMaskTypeClear : 用戶不可以做其他操作
SVProgressHUDMaskTypeBlack :　用戶不可以做其他操作，並且背景色是黑色
SVProgressHUDMaskTypeGradient :用戶不可以做其他操作，並且背景色是漸變的

除了插件自帶的幾種效果，還可以自定義背景色的效果
[SVProgressHUD setBackgroundLayerColor:[[UIColor redColor] colorWithAlphaComponent:0.4]];
[SVProgressHUD setDefaultMaskType:SVProgressHUDMaskTypeCustom];

1.4.3 SVProgressHUDStyle 彈出窗的樣式

 [SVProgressHUD setDefaultStyle:SVProgressHUDStyleLight]; 窗的背景塊是白色，字跟圓圈是黑色
 [SVProgressHUD setDefaultStyle:SVProgressHUDStyleDark]; 窗的背景塊是黑色，字跟圓圈是白色

若要自定義必須先設setDefaultStyle為SVProgressHUDStyleCustom,再進行setForegroundColor,setBackgroundColor的配置.

1.5:相關代碼

1.5.1 SVProgressHUD消息的時間

+ (NSTimeInterval)displayDurationForString:(NSString*)string {
    return MAX((float)string.length * 0.06 + 0.5, [self sharedView].minimumDismissTimeInterval);
}

設置一個最大值，至少是0.5秒，其它時間按提示的文本字數長度決定；

1.5.2 設定某個效果不影響全局屬性

+ (void)showSuccessWithStatus:(NSString*)status maskType:(SVProgressHUDMaskType)maskType {
    SVProgressHUDMaskType existingMaskType = [self sharedView].defaultMaskType;
    [self setDefaultMaskType:maskType];
    [self showSuccessWithStatus:status];
    [self setDefaultMaskType:existingMaskType];
}

首先保存全局的效果值，然後顯示當前的效果，完成後又把當前的效果值換成剛才的全局效果，這樣就可以兼容全局效果跟本次效果的轉換；

1.5.3通知並傳遞內容

創建消息通知：

    [[NSNotificationCenter defaultCenter] postNotificationName:SVProgressHUDDidReceiveTouchEventNotification
                                                        object:self
                                                      userInfo:[self notificationUserInfo]];

傳遞的內容：

- (NSDictionary*)notificationUserInfo{
    return (self.statusLabel.text ? @{SVProgressHUDStatusUserInfoKey : self.statusLabel.text} : nil);
}

把當前提示的內容傳遞給通知，方便後面在接收到消息時可以做處理；

二：知識點

2.1 使用 __attribute__, deprecated 關鍵字表示已過時的API

+ (void)showWithMaskType:(SVProgressHUDMaskType)maskType __attribute__((deprecated("Use show and setDefaultMaskType: instead.")));

此方法已經過時了，如果在項目中有運用到此方法編譯器就會報出相應的警告；如下面截圖，就是用到此方法時報的警告；

知識點擴展(其它可以見__attribute__是GNU C特色之一,在iOS用的比較廣泛)：

a:unavailable告訴編譯器該方法不可用

作用：告訴編譯器該方法不可用，如果強行調用編譯器會提示錯誤。比如某個類在構造的時候不想直接通過init來初始化，只能通過特定的初始化方法，就可以將init方法標記為unavailable。用法：__attribute__((unavailable))

例子：

#define UNAVAILABLE_ATTRIBUTE __attribute__((unavailable))
#define NS_UNAVAILABLE UNAVAILABLE_ATTRIBUTE

#import <Foundation/Foundation.h>

@interface Person : NSObject
@property(nonatomic,copy) NSString *name;
@property(nonatomic,assign) NSUInteger age;

- (instancetype)init NS_UNAVAILABLE;
- (instancetype)initWithName:(NSString *)name age:(NSUInteger)age;

@end

b:屬性後面加UI_APPEARANCE_SELECTOR表示這個是影響全局

@property (assign, nonatomic) SVProgressHUDStyle defaultStyle UI_APPEARANCE_SELECTOR;                   // default is SVProgressHUDStyleLight
@property (assign, nonatomic) SVProgressHUDMaskType defaultMaskType UI_APPEARANCE_SELECTOR;             // default is SVProgressHUDMaskTypeNone
@property (assign, nonatomic) SVProgressHUDAnimationType defaultAnimationType UI_APPEARANCE_SELECTOR;   // default is SVProgressHUDAnimationTypeFlat
@property (assign, nonatomic) CGSize minimumSize UI_APPEARANCE_SELECTOR;            // default is CGSizeZero, can be used to avoid resizing for a larger message

2.2 關鍵字extern 用於修飾常量可以讓外面的引用文件應用

在頭文件中使用extern來聲明全局常量，並在相關實現文件中定義其值，這種常量要出現在全局符號表中，所以其名稱應加以區別，通常用與之相關的類名做前綴；

在SVProgressHUD.h文件中定義的這些const

extern NSString * const SVProgressHUDDidReceiveTouchEventNotification;
extern NSString * const SVProgressHUDDidTouchDownInsideNotification;
extern NSString * const SVProgressHUDWillDisappearNotification;
extern NSString * const SVProgressHUDDidDisappearNotification;
extern NSString * const SVProgressHUDWillAppearNotification;
extern NSString * const SVProgressHUDDidAppearNotification;
extern NSString * const SVProgressHUDStatusUserInfoKey;

@interface SVProgressHUD : UIView
@end

然後在SVProgressHUD.m

NSString * const SVProgressHUDDidReceiveTouchEventNotification = @"SVProgressHUDDidReceiveTouchEventNotification";
NSString * const SVProgressHUDDidTouchDownInsideNotification = @"SVProgressHUDDidTouchDownInsideNotification";
NSString * const SVProgressHUDWillDisappearNotification = @"SVProgressHUDWillDisappearNotification";
NSString * const SVProgressHUDDidDisappearNotification = @"SVProgressHUDDidDisappearNotification";
NSString * const SVProgressHUDWillAppearNotification = @"SVProgressHUDWillAppearNotification";
NSString * const SVProgressHUDDidAppearNotification = @"SVProgressHUDDidAppearNotification";
NSString * const SVProgressHUDStatusUserInfoKey = @"SVProgressHUDStatusUserInfoKey";


@interface SVProgressHUD ()
@end

就可以在其它地方進行運用：

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(handleNotification:)
                                                 name:SVProgressHUDWillAppearNotification
                                               object:nil];
    
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(handleNotification:)
                                                 name:SVProgressHUDDidAppearNotification
                                               object:nil];
    
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(handleNotification:)
                                                 name:SVProgressHUDWillDisappearNotification
                                               object:nil];
    
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(handleNotification:)
                                                 name:SVProgressHUDDidDisappearNotification
                                               object:nil];
}

- (void)handleNotification:(NSNotification *)notification {
    NSLog(@"Notification recieved: %@", notification.name);
    NSLog(@"Status user info key: %@", notification.userInfo[SVProgressHUDStatusUserInfoKey]);
}

2.3生成Bundle包及運用

Bundle簡單理解，就是資源文件包。我們將許多圖片、XIB、文本文件組織在一起，打包成一個Bundle文件。方便在其他項目中引用包內的資源。Bundle是靜態的，也就是說，我們包含到包中的資源文件作為一個資源包是不參加項目編譯的。也就意味著，bundle包中不能包含可執行的文件。它僅僅是作為資源，被解析成為特定的2進制數據。默認生成的配置跟strings文件都是可以刪除；將要使用的bundle集成到項目中後，就可以使用了。需要注意的就是，bundle是靜態的，不進行編譯的資源文件。所以，要使用bundle中的資源，就需要找到相應的資源路徑。

        NSBundle *bundle = [NSBundle bundleForClass:[SVProgressHUD class]];
        NSURL *url = [bundle URLForResource:@"SVProgressHUD" withExtension:@"bundle"];
        NSBundle *imageBundle = [NSBundle bundleWithURL:url];
        
        UIImage* infoImage = [UIImage imageWithContentsOfFile:[imageBundle pathForResource:@"info" ofType:@"png"]];
        UIImage* successImage = [UIImage imageWithContentsOfFile:[imageBundle pathForResource:@"success" ofType:@"png"]];
        UIImage* errorImage = [UIImage imageWithContentsOfFile:[imageBundle pathForResource:@"error" ofType:@"png"]];

當然也可以定義宏來簡化代碼：

#define MYBUNDLE_NAME @ "SVProgressHUD.bundle"
#define MYBUNDLE_PATH [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent: MYBUNDLE_NAME]
#define MYBUNDLE [NSBundle bundleWithPath: MYBUNDLE_PATH]

其它一些擴展：

NSString * bundlePath = [[ NSBundle mainBundle] pathForResource: @ "MyBundle" ofType :@ "bundle"];
NSBundle *resourceBundle = [NSBundle bundleWithPath:bundlePath];
UIViewController *vc = [[UIViewController alloc] initWithNibName:@"vc_name" bundle:resourceBundle];

圖片獲得bundle中的資源

UIImageView *imgView=[[UIImageView alloc] initWithFrame:CGRectMake(50, 50, 50, 50)];
UIImage *image = [UIImage imageNamed:@"MyBundle.bundle/img_collect_success"];
[imgView setImage:image];

或者

UIImageView *imgView=[[UIImageView alloc] initWithFrame:CGRectMake(50, 50, 50, 50)];
NSString *imgPath= [bundlePath stringByAppendingPathComponent :@"img_collect_success.png"];
UIImage *image_1=[UIImage imageWithContentsOfFile:imgPath];
[imgView setImage:image_1];

2.4 UIView的Tint Color屬性

在iOS 7後，UIView新增加了一個tintColor屬性，這個屬性定義了一個非默認的著色顏色值，其值的設置會影響到以視圖為根視圖的整個視圖層次結構。它主要是應用到諸如app圖標、導航欄、按鈕等一些控件上，以獲取一些有意思的視覺效果。

默認情況下，一個視圖的tintColor是為nil的，這意味著視圖將使用父視圖的tint color值。當我們指定了一個視圖的tintColor後，這個色值會自動傳播到視圖層次結構(以當前視圖為根視圖)中所有的子視圖上。如果系統在視圖層次結構中沒有找到一個非默認的tintColor值，則會使用系統定義的顏色值(藍色，RGB值為[0,0.478431,1]，我們可以在IB中看到這個顏色)。因此，這個值總是會返回一個顏色值，即我們沒有指定它。

如果我們想指定整個App的tint color，則可以通過設置window的tint color。這樣同一個window下的所有子視圖都會繼承此tint color。

若想了解關於Tint Color屬性可以查看這篇文章

2.5 UIImage的渲染模式：UIImage.renderingMode

正如2.4點所介紹那些，在IOS7以後UIImage也會受到Tint Color的影響，著色（Tint Color）是iOS7界面中的一個.設置UIImage的渲染模式：UIImage.renderingMode重大改變，你可以設置一個UIImage在渲染時是否使用當前視圖的Tint Color。UIImage新增了一個只讀屬性：renderingMode，對應的還有一個新增方法：imageWithRenderingMode:，它使用UIImageRenderingMode枚舉值來設置圖片的renderingMode屬性。該枚舉中包含下列值：

UIImageRenderingModeAutomatic  // 根據圖片的使用環境和所處的繪圖上下文自動調整渲染模式（默認）。  
UIImageRenderingModeAlwaysOriginal   // 始終繪制圖片原始狀態，不使用Tint Color。  
UIImageRenderingModeAlwaysTemplate   // 始終根據Tint Color繪制圖片，忽略圖片的顏色信息。 

運用：

UIImage *img = [UIImage imageNamed:@ "myimage" ]; 
img = [img imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate]; 

當然也可以兼容，是否有imageWithRenderingMode再做處理：

        if ([[UIImage class] instancesRespondToSelector:@selector(imageWithRenderingMode:)]) {
            _infoImage = [infoImage imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];
            _successImage = [successImage imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];
            _errorImage = [errorImage imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];
        } else {
            _infoImage = infoImage;
            _successImage = successImage;
            _errorImage = errorImage;
        }

2.6UIControl

在開發應用的時候，經常會用到各種各樣的控件，諸如按鈕(UIButton)、滑塊(UISlider)、分頁控件(UIPageControl)等。這些控件用來與用戶進行交互，響應用戶的操作。我們查看這些類的繼承體系，可以看到它們都是繼承於UIControl類。UIControl是控件類的基類，它是一個抽象基類，我們不能直接使用UIControl類來實例化控件，它只是為控件子類定義一些通用的接口，並提供一些基礎實現，以在事件發生時，預處理這些消息並將它們發送到指定目標對象上。UIControl也是UIView的子類；想詳細了解UIControl可以查看這文章;下面創建一個控件實例：

#import <UIKit/UIKit.h>

@interface ImageControl : UIControl

- (instancetype)initWithFrame:(CGRect)frame title:(NSString *)title image:(UIImage *)image;

@end

#import "ImageControl.h"

@implementation ImageControl {
    
    UILabel     *_label;
    UIImageView *_imageView;
}

- (instancetype)initWithFrame:(CGRect)frame title:(NSString *)title image:(UIImage *)image {
    
    self = [super initWithFrame:frame];
    
    if (self) {
        
        self.backgroundColor = [UIColor clearColor];
        self.layer.borderWidth = 1.0f;
        self.layer.borderColor = [UIColor grayColor].CGColor;
        self.layer.cornerRadius = 5.0f;
        self.layer.masksToBounds = YES;
        
        CGFloat width = CGRectGetWidth(self.bounds);
        CGFloat height = CGRectGetHeight(self.bounds);
        
        [self addSubview:({
            
            _imageView = [[UIImageView alloc] initWithFrame:self.bounds];
            _imageView.image = image;
            _imageView;
        })];
        
        
        [self addSubview:({
            _label = [[UILabel alloc] initWithFrame:(CGRect){0.0f, height - 30.0f, width, 30.0f}];
            _label.textAlignment = NSTextAlignmentCenter;
            _label.textColor = [UIColor whiteColor];
            _label.text = title;
            _label;
        })];
    }
    
    return self;
}

- (void)sendAction:(SEL)action to:(id)target forEvent:(UIEvent *)event {
    
    // 由對象本身來處理事件
    [super sendAction:@selector(handleAction:) to:self forEvent:event];
}

- (BOOL)beginTrackingWithTouch:(UITouch *)touch withEvent:(UIEvent *)event {
    [super beginTrackingWithTouch:touch withEvent:event];
    
    NSLog(@"Begin %d", self.tracking);
    
    return YES;
}

- (BOOL)continueTrackingWithTouch:(UITouch *)touch withEvent:(UIEvent *)event {
    [super continueTrackingWithTouch:touch withEvent:event];
    
    NSLog(@"Continue %d %@", self.tracking, (self.touchInside ? @"YES" : @"NO"));
    
    return YES;
}

- (void)endTrackingWithTouch:(UITouch *)touch withEvent:(UIEvent *)event {
    [super endTrackingWithTouch:touch withEvent:event];
    
    CGPoint position = [touch locationInView:self];
    
    if (CGRectContainsPoint(_label.frame, position)) {
        
        // 在此觸發一個UIControlEventTouchUpInside事件行為
        [self sendActionsForControlEvents:UIControlEventTouchUpInside];
    }
    
    NSLog(@"End %d", self.tracking);
}

- (void)cancelTrackingWithEvent:(UIEvent *)event {
    [super cancelTrackingWithEvent:event];
    
    NSLog(@"Cancel");
}

- (void)handleAction:(id)sender {
    
    NSLog(@"handle Action");
    
    NSLog(@"target-actoin: %@", self.allTargets);
}

//- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
//    [super touchesBegan:touches withEvent:event];
//    
//    NSLog(@"Touch began");
//}
//
//- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
//    
//    [super touchesMoved:touches withEvent:event];
//    
//    NSLog(@"Touch Moved");
//}
//
//- (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
//    [super touchesEnded:touches withEvent:event];
//    
//    NSLog(@"Touch End");
//}
//
//- (void)touchesCancelled:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
//    
//    [super touchesCancelled:touches withEvent:event];
//    
//    NSLog(@"Touch Cancel");
//}

@end

而在SVProgressHUD中的運用如下：

- (UIControl*)overlayView {
    if(!_overlayView) {
#if !defined(SV_APP_EXTENSIONS)
        CGRect windowBounds = [[[UIApplication sharedApplication] delegate] window].bounds;
        _overlayView = [[UIControl alloc] initWithFrame:windowBounds];
#else
        _overlayView = [[UIControl alloc] initWithFrame:[UIScreen mainScreen].bounds];
#endif
        _overlayView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
        _overlayView.backgroundColor = [UIColor clearColor];
        [_overlayView addTarget:self action:@selector(overlayViewDidReceiveTouchEvent:forEvent:) forControlEvents:UIControlEventTouchDown];
    }
    return _overlayView;
}