在开发中经常遇到需要添加hud的情形，每次添加的代码都在10行左右，遂新建一个ViewController的Category来添加hud。由于分类不能直接添加属性，就考虑到了runtime。
下面讲具体的实施步骤
新建工程－－新建文件，选择Objective-C File 如下图：
屏幕快照 2016-01-19 21.43.58.png
导入MBProgressHUD, 现在项目结构如图：
屏幕快照 2016-01-19 21.48.11.png
在UIViewController+HUD.h中导入MBProgressHUD.h，
#import <UIKit/UIKit.h>
#import "MBProgressHUD.h"
@interface UIViewController (HUD)
@end
在UIViewController+HUD.m中导入runtime.h，并添加hud属性：
#import "UIViewController+HUD.h"
#import <objc/runtime.h>
@interface UIViewController(Private)
@property (nonatomic, strong) MBProgressHUD *progressHud;
@end
@implementation UIViewController (HUD)
const char *kHudKey = "ProgressHUD_Key";
@end
接下来是关键的一步－设置hud的setter与getter方法：
- (void)setProgressHud:(MBProgressHUD *)progressHud
{
objc_setAssociatedObject(self, kHudKey, progressHud, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
- (MBProgressHUD *)progressHud
{
MBProgressHUD *hud = objc_getAssociatedObject(self, kHudKey);
if (!hud) {
UIView *view = self.navigationController.view;
hud = [[MBProgressHUD alloc] initWithView:view];
hud.removeFromSuperViewOnHide = YES;
[view addSubview:hud];
self.progressHud = hud;
}
return hud;
}
在setter中设置连接， 在getter中初始化。
好了，接下来就可以正常使用属性了，现在，我们对hud进行扩展。
写两个基本的show、hide方法，其余的实现在其基础上变化即可：
#pragma mark - Private
- (void)showHudWithMessage:(NSString *)message model:(MBProgressHUDMode)mode
{
if (self.progressHud.taskInProgress) {
return;
}
self.progressHud.taskInProgress = YES;
self.progressHud.mode = mode ?: MBProgressHUDModeIndeterminate;
self.progressHud.labelText = message;
self.progressHud.labelFont = [UIFont systemFontOfSize:15];
[self.progressHud show:YES];
[self.progressHud hide:YES afterDelay:15];
}
- (void)hideHudWithMessage:(NSString *)message image:(UIImage *)image
{
self.progressHud.customView = [[UIImageView alloc] initWithImage:image];
self.progressHud.mode = MBProgressHUDModeCustomView;
self.progressHud.labelText = message;
self.progressHud.labelFont = [UIFont systemFontOfSize:15];
[self.progressHud show:YES];
[self performSelector:@selector(hideHud) withObject:nil afterDelay:0.7];
}
再实现下面的方法大概就够用了：
- (void)showHud;
- (void)showHudWithMessage:(NSString *)message;
- (void)showDeterminateHudWithMessage:(NSString *)message;
- (void)changeHudProgress:(double)precent;
- (void)hideHud;
- (void)hideHudWithSuccessMessage:(NSString *)message;
- (void)hideHudWithErrorMessage:(NSString *)message;
具体的实现直接看代码吧！
https://github.com/Xigtun/RuntimeDemo
