转载：多年iOS开发经验总结
转载：http://www.jianshu.com/p/1ff9e44ccc78
总结了几个月的东西终于能和大家分享了，不多说，直接看东西！
1、禁止手机睡眠
[UIApplication sharedApplication].idleTimerDisabled = YES;2、隐藏某行cell
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
// 如果是你需要隐藏的那一行，返回高度为0
if(indexPath.row == YouWantToHideRow)
return 0;
return 44;
}
// 然后再你需要隐藏cell的时候调用
[self.tableView beginUpdates];
[self.tableView endUpdates];3、禁用button高亮
button.adjustsImageWhenHighlighted = NO;
或者在创建的时候
UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];4、tableview遇到这种报错failed to obtain a cell from its dataSource
是因为你的cell被调用的早了。先循环使用了cell，后又创建cell。顺序错了
可能原因：1、xib的cell没有注册 2、内存中已经有这个cell的缓存了(也就是说通过你的cellId找到的cell并不是你想要的类型)，这时候需要改下cell的标识
5、cocoa pods报这个错误：unable to access 'https://github.com/facebook/pop.git/': Operation timed out after 0 milliseconds with 0 out of 0 bytes received
解决办法：原因可能是网络问题，网络请求超时了，只需要重试就行了
6、cocoa pods 出现ERROR: While executing gem ... (Errno::EPERM)
7、动画切换window的根控制器
// options是动画选项
[UIView transitionWithView:[UIApplication sharedApplication].keyWindow duration:0.5f options:UIViewAnimationOptionTransitionCrossDissolve animations:^{
BOOL oldState = [UIView areAnimationsEnabled];
[UIView setAnimationsEnabled:NO];
[UIApplication sharedApplication].keyWindow.rootViewController = [RootViewController new];
[UIView setAnimationsEnabled:oldState];
} completion:^(BOOL finished) {
}];8、去除数组中重复的对象
NSArray *newArr = [oldArr valueForKeyPath:@“@distinctUnionOfObjects.self"];9、编译的时候遇到 no such file or directory: ／users／apple／XXX
是因为编译的时候，在此路径下找不到这个文件，解决这个问题，首先是是要检查缺少的文件是不是在工程中，如果不在工程中，需要从本地拖进去，如果发现已经存在工程中了，或者拖进去还是报错，这时候需要去build phases中搜索这个文件，这时候很可能会搜出现两个相同的文件，这时候，有一个路径是正确的，删除另外一个即可。如果删除了还是不行，需要把两个都删掉，然后重新往工程里拖进这个文件即可
build phases
10、iOS8系统中，tableView最好实现下-tableView: heightForRowAtIndexPath:这个代理方法，要不然在iOS8中可能就会出现显示不全或者无法响应事件的问题
11、iOS8中实现侧滑功能的时候这个方法必须实现，要不然在iOS8中无法侧滑
// 必须写的方法，和editActionsForRowAtIndexPath配对使用，里面什么不写也行
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
}12、三个通知
NSSystemTimeZoneDidChangeNotification监听修改时间界面的两个按钮状态变化
UIApplicationSignificantTimeChangeNotification 监听用户改变时间 （只要点击自动设置按钮就会调用） NSSystemClockDidChangeNotification 监听用户修改时间（时间不同才会调用）
13、SDWebImage本地缓存有时候会害人。如果之前缓存过一张图片，即使下次服务器换了这张图片，但是图片url没换，用sdwebimage下载下来的还是以前那张,所以遇到这种问题，不要先去怼服务器，清空下缓存再试就好了。
14、上线前注意：
1）、删掉代码中所有的测试代码
2）、如果后台有审核模式，提醒后台开启此模式
3）、主流程再跑一跑
4）、全局搜索waring，检查所有标记waring的地方
15、跳进app权限设置
// 跳进app设置
if (UIApplicationOpenSettingsURLString != NULL) {
NSURL *url = [NSURL URLWithString:UIApplicationOpenSettingsURLString];
[[UIApplication sharedApplication] openURL:url];
}
}16、给一个view截图
UIGraphicsBeginImageContextWithOptions(view.bounds.size, YES, 0.0);
[view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();17、开发中如果要动态修改tableView的tableHeaderView或者tableFooterView的高度，需要给tableView重新设置，而不是直接更改高度。正确的做法是重新设置一下tableView.tableFooterView = 更改过高度的view。为什么？其实在iOS8以上直接改高度是没有问题的，在iOS8中出现了contentSize不准确的问题，这是解决办法。
18、注意对象为nil的时候，调用此对象分类的方法不会执行
19、collectionView的内容小于其宽高的时候是不能滚动的，设置可以滚动：
collectionView.alwaysBounceHorizontal = YES;
collectionView.alwaysBounceVertical = YES;20、设置navigationBar上的title颜色和大小
[self.navigationController.navigationBar setTitleTextAttributes:@{NSForegroundColorAttributeName : [UIColor youColor], NSFontAttributeName : [UIFont systemFontOfSize:15]}]21、颜色转图片
+ (UIImage *)cl_imageWithColor:(UIColor *)color {
CGRect rect = CGRectMake(0.0f, 0.0f, 1.0f, 1.0f);
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(context, [color CGColor]);
CGContextFillRect(context, rect);
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}22、view设置圆角
#define ViewBorderRadius(View, Radius, Width, Color)\
\
[View.layer setCornerRadius:(Radius)];\
[View.layer setMasksToBounds:YES];\
[View.layer setBorderWidth:(Width)];\
[View.layer setBorderColor:[Color CGColor]] // view圆角23、强／弱引用
#define WeakSelf(type) __weak typeof(type) weak##type = type; // weak
#define StrongSelf(type) __strong typeof(type) type = weak##type; // strong24、由角度转换弧度
#define DegreesToRadian(x) (M_PI * (x) / 180.0)25、由弧度转换角度
#define RadianToDegrees(radian) (radian*180.0)/(M_PI)26、获取图片资源
#define GetImage(imageName) [UIImage imageNamed:[NSString stringWithFormat:@"%@",imageName]]27、获取temp
#define PathTemp NSTemporaryDirectory()28、获取沙盒 Document
#define PathDocument [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject]29、获取沙盒 Cache
#define PathCache [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) firstObject]30、GCD代码只执行一次
#define kDISPATCH_ONCE_BLOCK(onceBlock) static dispatch_once_t onceToken; dispatch_once(&onceToken, onceBlock);31、自定义NSLog
#ifdef DEBUG
#define NSLog(fmt, ...) NSLog((@"%s [Line %d] " fmt), __PRETTY_FUNCTION__, __LINE__, ##__VA_ARGS__)
#else
#define NSLog(...)
#endif32、Font
#define FontL(s) [UIFont systemFontOfSize:s weight:UIFontWeightLight]
#define FontR(s) [UIFont systemFontOfSize:s weight:UIFontWeightRegular]
#define FontB(s) [UIFont systemFontOfSize:s weight:UIFontWeightBold]
#define FontT(s) [UIFont systemFontOfSize:s weight:UIFontWeightThin]
#define Font(s) FontL(s)33、FORMAT
#define FORMAT(f, ...) [NSString stringWithFormat:f, ## __VA_ARGS__]34、在主线程上运行
#define kDISPATCH_MAIN_THREAD(mainQueueBlock) dispatch_async(dispatch_get_main_queue(), mainQueueBlock);35、开启异步线程
#define kDISPATCH_GLOBAL_QUEUE_DEFAULT(globalQueueBlock) dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), globalQueueBlocl);36、通知
#define NOTIF_ADD(n, f) [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(f) name:n object:nil]
#define NOTIF_POST(n, o) [[NSNotificationCenter defaultCenter] postNotificationName:n object:o]
#define NOTIF_REMV() [[NSNotificationCenter defaultCenter] removeObserver:self]37、随机颜色
+ (UIColor *)RandomColor {
NSInteger aRedValue = arc4random() % 255;
NSInteger aGreenValue = arc4random() % 255;
NSInteger aBlueValue = arc4random() % 255;
UIColor *randColor = [UIColor colorWithRed:aRedValue / 255.0f green:aGreenValue / 255.0f blue:aBlueValue / 255.0f alpha:1.0f];
return randColor;
}38、获取window
+(UIWindow*)getWindow {
UIWindow* win = nil; //[UIApplication sharedApplication].keyWindow;
for (id item in [UIApplication sharedApplication].windows) {
if ([item class] == [UIWindow class]) {
if (!((UIWindow*)item).hidden) {
win = item;
break;
}
}
}
return win;
}39、修改textField的placeholder的字体颜色、大小
[textField setValue:[UIColor redColor] forKeyPath:@"_placeholderLabel.textColor"];
[textField setValue:[UIFont boldSystemFontOfSize:16] forKeyPath:@"_placeholderLabel.font"];40、统一收起键盘
[[[UIApplication sharedApplication] keyWindow] endEditing:YES];41、控制屏幕旋转，在控制器中写
/** 是否支持自动转屏 */
- (BOOL)shouldAutorotate {
return YES;
}
/** 支持哪些屏幕方向 */
- (UIInterfaceOrientationMask)supportedInterfaceOrientations {
return UIInterfaceOrientationMaskLandscapeLeft | UIInterfaceOrientationMaskLandscapeRight;
}
/** 默认的屏幕方向（当前ViewController必须是通过模态出来的UIViewController（模态带导航的无效）方式展现出来的，才会调用这个方法） */
- (UIInterfaceOrientation)preferredInterfaceOrientationForPresentation {
return UIInterfaceOrientationLandscapeLeft | UIInterfaceOrientationLandscapeRight;
}42、获取app缓存大小
- (CGFloat)getCachSize {
NSUInteger imageCacheSize = [[SDImageCache sharedImageCache] getSize];
//获取自定义缓存大小
//用枚举器遍历 一个文件夹的内容
//1.获取 文件夹枚举器
NSString *myCachePath = [NSHomeDirectory() stringByAppendingPathComponent:@"Library/Caches"];
NSDirectoryEnumerator *enumerator = [[NSFileManager defaultManager] enumeratorAtPath:myCachePath];
__block NSUInteger count = 0;
//2.遍历
for (NSString *fileName in enumerator) {
NSString *path = [myCachePath stringByAppendingPathComponent:fileName];
NSDictionary *fileDict = [[NSFileManager defaultManager] attributesOfItemAtPath:path error:nil];
count += fileDict.fileSize;//自定义所有缓存大小
}
// 得到是字节 转化为M
CGFloat totalSize = ((CGFloat)imageCacheSize+count)/1024/1024;
return totalSize;
}43、清理app缓存
- (void)handleClearView {
//删除两部分
//1.删除 sd 图片缓存
//先清除内存中的图片缓存
[[SDImageCache sharedImageCache] clearMemory];
//清除磁盘的缓存
[[SDImageCache sharedImageCache] clearDisk];
//2.删除自己缓存
NSString *myCachePath = [NSHomeDirectory() stringByAppendingPathComponent:@"Library/Caches"];
[[NSFileManager defaultManager] removeItemAtPath:myCachePath error:nil];
}44、模型转字典
static NSSet *classes;
- (NSMutableDictionary *)getParameterDictionary {
NSMutableDictionary *dict = [NSMutableDictionary dictionary];
Class c = self.class;
while (c) {
unsigned count;
objc_property_t *properties = class_copyPropertyList([c class], &count);
for (int i = 0; i < count; i++) {
NSString *key = [NSString stringWithUTF8String:property_getName(properties[i])];
dict[key] = [self valueForKey:key];
}
free(properties);
// 获得父类
c = class_getSuperclass(c);
if ([self isClassFromFoundation:c]) break;
}
return dict;
}
- (BOOL)isClassFromFoundation:(Class)c
{
if (c == [NSObject class] || c == [NSManagedObject class]) return YES;
__block BOOL result = NO;
[[self foundationClasses] enumerateObjectsUsingBlock:^(Class foundationClass, BOOL *stop) {
if ([c isSubclassOfClass:foundationClass]) {
result = YES;
*stop = YES;
}
}];
return result;
}
- (NSSet *)foundationClasses
{
if (classes == nil) {
// 集合中没有NSObject，因为几乎所有的类都是继承自NSObject，具体是不是NSObject需要特殊判断
classes = [NSSet setWithObjects:
[NSURL class],
[NSDate class],
[NSValue class],
[NSData class],
[NSError class],
[NSArray class],
[NSDictionary class],
[NSString class],
[NSAttributedString class], nil];
}
return classes;
}45、交换两个方法实现
Class aClass = [self class];
SEL originalSelector = @selector(viewWillAppear:);
SEL swizzledSelector = @selector(xxx_viewWillAppear:);
Method originalMethod = class_getInstanceMethod(aClass, originalSelector);
Method swizzledMethod = class_getInstanceMethod(aClass, swizzledSelector);
BOOL didAddMethod =
class_addMethod(aClass,
originalSelector,
method_getImplementation(swizzledMethod),
method_getTypeEncoding(swizzledMethod));
if (didAddMethod) {
class_replaceMethod(aClass,
swizzledSelector,
method_getImplementation(originalMethod),
method_getTypeEncoding(originalMethod));
} else {
method_exchangeImplementations(originalMethod, swizzledMethod);
}46、打印百分号和引号
NSLog(@"%%");
NSLog(@"\"");47、几个常用权限判断
if ([CLLocationManager authorizationStatus] ==kCLAuthorizationStatusDenied) {
NSLog(@"没有定位权限");
}
AVAuthorizationStatus statusVideo = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo];
if (statusVideo == AVAuthorizationStatusDenied) {
NSLog(@"没有摄像头权限");
}
//是否有麦克风权限
AVAuthorizationStatus statusAudio = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeAudio];
if (statusAudio == AVAuthorizationStatusDenied) {
NSLog(@"没有录音权限");
}
[PHPhotoLibrary requestAuthorization:^(PHAuthorizationStatus status) {
if (status == PHAuthorizationStatusDenied) {
NSLog(@"没有相册权限");
}
}];48、获取手机型号
+ (NSString *)getDeviceInfo {
struct utsname systemInfo;
uname(&systemInfo);
NSString *platform = [NSString stringWithCString:systemInfo.machine encoding:NSASCIIStringEncoding];
if ([platform isEqualToString:@"iPhone1,1"]) return @"iPhone 2G";
if ([platform isEqualToString:@"iPhone1,2"]) return @"iPhone 3G";
if ([platform isEqualToString:@"iPhone2,1"]) return @"iPhone 3GS";
if ([platform isEqualToString:@"iPhone3,1"]) return @"iPhone 4";
if ([platform isEqualToString:@"iPhone3,2"]) return @"iPhone 4";
if ([platform isEqualToString:@"iPhone3,3"]) return @"iPhone 4";
if ([platform isEqualToString:@"iPhone4,1"]) return @"iPhone 4S";
if ([platform isEqualToString:@"iPhone5,1"]) return @"iPhone 5";
if ([platform isEqualToString:@"iPhone5,2"]) return @"iPhone 5";
if ([platform isEqualToString:@"iPhone5,3"]) return @"iPhone 5c";
if ([platform isEqualToString:@"iPhone5,4"]) return @"iPhone 5c";
if ([platform isEqualToString:@"iPhone6,1"]) return @"iPhone 5s";
if ([platform isEqualToString:@"iPhone6,2"]) return @"iPhone 5s";
if ([platform isEqualToString:@"iPhone7,1"]) return @"iPhone 6 Plus";
if ([platform isEqualToString:@"iPhone7,2"]) return @"iPhone 6";
if ([platform isEqualToString:@"iPhone8,1"]) return @"iPhone 6s";
if ([platform isEqualToString:@"iPhone8,2"]) return @"iPhone 6s Plus";
// 日行两款手机型号均为日本独占，可能使用索尼FeliCa支付方案而不是苹果支付
if ([platform isEqualToString:@"iPhone9,1"]) return @"国行、日版、港行iPhone 7";
if ([platform isEqualToString:@"iPhone9,2"]) return @"港行、国行iPhone 7 Plus";
if ([platform isEqualToString:@"iPhone9,3"]) return @"美版、台版iPhone 7";
if ([platform isEqualToString:@"iPhone9,4"]) return @"美版、台版iPhone 7 Plus";
if ([platform isEqualToString:@"iPhone8,4"]) return @"iPhone SE";
if ([platform isEqualToString:@"iPod1,1"]) return @"iPod Touch 1G";
if ([platform isEqualToString:@"iPod2,1"]) return @"iPod Touch 2G";
if ([platform isEqualToString:@"iPod3,1"]) return @"iPod Touch 3G";
if ([platform isEqualToString:@"iPod4,1"]) return @"iPod Touch 4G";
if ([platform isEqualToString:@"iPod5,1"]) return @"iPod Touch 5G";
if ([platform isEqualToString:@"iPad1,1"]) return @"iPad 1G";
if ([platform isEqualToString:@"iPad2,1"]) return @"iPad 2";
if ([platform isEqualToString:@"iPad2,2"]) return @"iPad 2";
if ([platform isEqualToString:@"iPad2,3"]) return @"iPad 2";
if ([platform isEqualToString:@"iPad2,4"]) return @"iPad 2";
if ([platform isEqualToString:@"iPad2,5"]) return @"iPad Mini 1G";
if ([platform isEqualToString:@"iPad2,6"]) return @"iPad Mini 1G";
if ([platform isEqualToString:@"iPad2,7"]) return @"iPad Mini 1G";
if ([platform isEqualToString:@"iPad3,1"]) return @"iPad 3";
if ([platform isEqualToString:@"iPad3,2"]) return @"iPad 3";
if ([platform isEqualToString:@"iPad3,3"]) return @"iPad 3";
if ([platform isEqualToString:@"iPad3,4"]) return @"iPad 4";
if ([platform isEqualToString:@"iPad3,5"]) return @"iPad 4";
if ([platform isEqualToString:@"iPad3,6"]) return @"iPad 4";
if ([platform isEqualToString:@"iPad4,1"]) return @"iPad Air";
if ([platform isEqualToString:@"iPad4,2"]) return @"iPad Air";
if ([platform isEqualToString:@"iPad4,3"]) return @"iPad Air";
if ([platform isEqualToString:@"iPad4,4"]) return @"iPad Mini 2G";
if ([platform isEqualToString:@"iPad4,5"]) return @"iPad Mini 2G";
if ([platform isEqualToString:@"iPad4,6"]) return @"iPad Mini 2G";
if ([platform isEqualToString:@"i386"]) return @"iPhone Simulator";