1：通用的weakify和strongify
/**
* 强弱引用转换，用于解决代码块（block）与强引用self之间的循环引用问题
* 调用方式: `@weakify_self`实现弱引用转换，`@strongify_self`实现强引用转换
*
* 示例：
* @weakify_self
* [obj block:^{
* @strongify_self
* self.PRoperty = something;
* }];*/#ifndef weakify_self#if__has_feature(objc_arc)#defineweakify_self autoreleasepool{} __weak __typeof__(self) weakSelf = self;#else#defineweakify_self autoreleasepool{} __block __typeof__(self) blockSelf = self;#endif#endif#ifndef strongify_self#if__has_feature(objc_arc)#definestrongify_self try{} @finally{} __typeof__(weakSelf) self = weakSelf;#else#definestrongify_self try{} @finally{} __typeof__(blockSelf) self = blockSelf;#endif#endif/**
* 强弱引用转换，用于解决代码块（block）与强引用对象之间的循环引用问题
* 调用方式: `@weakify(object)`实现弱引用转换，`@strongify(object)`实现强引用转换
*
* 示例：
* @weakify(object)
* [obj block:^{
* @strongify(object)
* strong_object = something;
* }];*/#ifndef weakify#if__has_feature(objc_arc)#defineweakify(object) autoreleasepool{} __weak __typeof__(object) weak##_##object = object;#else#defineweakify(object) autoreleasepool{} __block __typeof__(object) block##_##object = object;#endif#endif#ifndef strongify#if__has_feature(objc_arc)#definestrongify(object) try{} @finally{} __typeof__(object) strong##_##object = weak##_##object;#else#definestrongify(object) try{} @finally{} __typeof__(object) strong##_##object = block##_##object;#endif#endif
运用（这两个宏一定成对出现，先weak再strong）：
@weakify(self);//定义了一个__weak的self_weak_变量[RACObserve(self, name) subscribeNext:^(NSString *name) {
@strongify(self);//局域定义了一个__strong的self指针指向self_weakself.outputLabel.text =name;
}];
2：objc runtime 动态增加属性
说明：给类扩展增加了一个新属性。通常下类扩展只允许添加方法。必须要先引入 objc/runtime.h，主要是下面两个方法：
赋值：
OBJC_EXPORTvoidobjc_setAssociatedObject(idobject,constvoid*key, id value, objc_AssociationPolicy policy)
获得值：
OBJC_EXPORT id objc_getAssociatedObject(idobject,constvoid*key)
实例（引用）：
UILabel+Associate.h
#import<UIKit/UIKit.h>@interface UILabel (Associate)- (void) setFlashColor:(UIColor *) flashColor;- (UIColor *) getFlashColor;
@end
UILabel+Associate.m
#import"UILabel+Associate.h"#import<objc/runtime.h>@implementation UILabel (Associate)staticcharflashColorKey;- (void) setFlashColor:(UIColor *) flashColor{
objc_setAssociatedObject(self,&flashColorKey, flashColor, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}- (UIColor *) getFlashColor{returnobjc_getAssociatedObject(self, &flashColorKey);
}
@end
调用代码：
UILabel *lab =[[UILabel alloc] init];
[lab setFlashColor:[UIColor redColor]];
NSLog(@"%@", [lab getFlashColor]);
3:navigationController popToViewController跳转到上上层
NSUInteger index=self.navigationController.viewControllers.count-3;
[self.navigationController popToViewController:[self.navigationController.viewControllers objectAtIndex:index] animated:YES];
如果动画是翻转页面，有可能是因为当前页面有键盘，可以先把键盘回收后，动作就变成正常的回退动画效果
4：App跳转到设置
UIapplication*app =[UIApplication sharedApplication];
NSURL*settingsURL =[NSURL URLWithString:UIApplicationOpenSettingsURLString];if([app canOpenURL:settingsURL]) {
[app openURL:settingsURL];
}
5:ios时间戳13位转换
IOS的时间转为13位时间戳//取当前时间的秒数，这边是到秒数NSTimeInterval time =[[NSDate date] timeIntervalSince1970];//到毫秒数，则再*1000longlongcurTime=[[NSDate date] timeIntervalSince1970]*1000;//ios生成的时间戳是10位13时间戳转为IOS的时间
NSString* timeStampString =@"1423189125874";
NSDate*date = [NSDate dateWithTimeIntervalSince1970:[timeStampString doubleValue] /1000];
或者
NSString* timeStampString =@"1423189125874";
NSTimeInterval _interval=[[timeStampString substringToIndex:10] doubleValue];
NSDate*date = [NSDate dateWithTimeIntervalSince1970:_interval];
6:iOS之整型(NSInteger)转换警告Values of type 'NSInteger' should not be used as format arguments;
苹果app支持arm64以后会有一个问题：NSInteger变成64位了，和原来的int （%d）不匹配，会报如下warning，
Values of type 'NSInteger' should not be used as format arguments; add an explicit cast to 'long' instead
解决办法：1、系统推荐方法 [NSString stringWithFormat:@“%ld", (long)number];2、强制转换 [NSString stringWithFormat:@"%d", (int)number];3、[NSString stringWithFormat:@“%@", @(number)];
7：本地语言添加文件（解决一些系统自带的Title为英语 比如Cannel Done等）
1：新建文件，Resource->Strings File 命名，2：然后点击这个.strings 右边有个Localization->Localizeation，增加一个英语；3：到Project-Info-Localizations 然后增加Chinses(Simplified) 选择.strings后就可以了
8:SDWebImage获得缓存大小，并对它进行清除
floattmpSize =[[SDImageCache sharedImageCache] getSize];
NSString*clearCacheName =@"当前缓存已清理";if(tmpSize>0) {
clearCacheName=tmpSize >=1? [NSString stringWithFormat:@"成功清理缓存(%.2fM)",tmpSize] : [NSString stringWithFormat:@"成功清理缓存(%.2fK)",tmpSize *1024];
}
[[SDImageCache sharedImageCache] clearDisk];
说明：直接sd_setImageWithURL 就会有缓存