颜色
#define UIColorFromARGB(rgbValue) [UIColor colorWithRed:((float)((rgbValue & 0xFF0000) >> 16))/255.0 green:((float)((rgbValue & 0xFF00) >> 8))/255.0 \
blue:((float)(rgbValue & 0xFF))/255.0 alpha:((float)((rgbValue & 0xFF000000) >> 24))/255.0]

1、改变 UITextField 占位文字 颜色
[_userName setValue:[UIColor whiteColor] forKeyPath:@"_placeholderLabel.textColor"];

2、禁止横屏 在Appdelegate 使用
- (NSUInteger)application:(UIApplication *)application supportedInterfaceOrientationsForWindow:(UIWindow *)window  
{  
    return UIInterfaceOrientationMaskPortrait;  
}

3、修改状态栏颜色 （默认黑色，修改为白色）
//1.在Info.plist中设置UIViewControllerBasedStatusBarAppearance 为NO
//2.在需要改变状态栏颜色的 AppDelegate中在 didFinishLaunchingWithOptions 方法中增加： 
[[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent];
//3.如果需要在单个ViewController中添加，在ViewDidLoad方法中增加：
[[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent];

4、模糊效果
    UIBlurEffect *effect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleLight];
    UIVisualEffectView *test = [[UIVisualEffectView alloc] initWithEffect:effect];
    test.frame = self.view.bounds;
    test.alpha = 0.5;
    [self.view addSubview:test];

5、强制横屏代码
#pragma mark - 强制横屏代码
- (BOOL)shouldAutorotate
{
    //是否支持转屏
    return NO;
}

- (UIInterfaceOrientationMask)supportedInterfaceOrientations
{
    //支持哪些转屏方向
    return UIInterfaceOrientationMaskLandscape;
}

- (UIInterfaceOrientation)preferredInterfaceOrientationForPresentation
{
    return UIInterfaceOrientationLandscapeRight;
}

- (BOOL)prefersStatusBarHidden
{
    return NO;
}

6、在状态栏显示有网络请求的提示器
   [UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
   [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;

7、相对路径
    $(SRCROOT)/

8、视图是否自动（只是把第一个自动）向下挪64
    self.automaticallyAdjustsScrollViewInsets = NO; //不让系统帮咱们把scrollView及其子类的视图向下调整64

9、 隐藏手机的状态栏
-(BOOL)prefersStatusBarHidden {
return YES;
}

10、代理的安全保护【断是否有代理，和代理是否执行了代理方法】
if (self.delegate && [self.delegate respondsToSelector:@selector(passValueWithArray:)]) {
    // make you codes

}

11、在ARC工程中导入MRC的类和在MRC工程中导入ARC的类
// 在ARC工程中导入MRC的类  我们选中工程->选中targets中的工程,然后选中Build Phases->在导入的类后边加入标记 -  fno-objc-arc
// 在MRC工程中导入ARC的类 路径与上面一致,在该类后面加上标记 -fobjc-arc

12、通过2D仿射函数实现小的动画效果(变大缩小) --可用于自定义pageControl中
[UIView animateWithDuration:0.3 animations:^{
    imageView.transform = CGAffineTransformMakeScale(2, 2);
} completion:^(BOOL finished) {
    imageView.transform = CGAffineTransformMakeScale(1.0, 1.0);
}];

13、查看系统所有字体
for (id familyName in [UIFont familyNames]) {
    NSLog(@"%@", familyName);
    for (id fontName in [UIFont fontNamesForFamilyName:familyName]) NSLog(@"  %@", fontName);
}

14、判断一个字符串是否为数字

NSCharacterSet *notDigits = [[NSCharacterSet decimalDigitCharacterSet] invertedSet];
if ([str rangeOfCharacterFromSet:notDigits].location == NSNotFound) {// 是数字

} else {// 不是数字

}

15、将一个view保存为pdf格式
- (void)createPDFfromUIView:(UIView*)aView saveToDocumentsWithFileName:(NSString*)aFilename
{
    NSMutableData *pdfData = [NSMutableData data];
    UIGraphicsBeginPDFContextToData(pdfData, aView.bounds, nil);
    UIGraphicsBeginPDFPage();
    CGContextRef pdfContext = UIGraphicsGetCurrentContext();
    [aView.layer renderInContext:pdfContext];
    UIGraphicsEndPDFContext();

    NSArray* documentDirectories = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask,YES);
    NSString* documentDirectory = [documentDirectories objectAtIndex:0];
    NSString* documentDirectoryFilename = [documentDirectory stringByAppendingPathComponent:aFilename];
    [pdfData writeToFile:documentDirectoryFilename atomically:YES];
    NSLog(@"documentDirectoryFileName: %@",documentDirectoryFilename);
}

16、让一个view在父视图中心
child.center = [parent convertPoint:parent.center fromView:parent.superview];

17、获取当前导航控制器下前一个控制器
- (UIViewController *)backViewController
{
    NSInteger myIndex = [self.navigationController.viewControllers indexOfObject:self];

    if ( myIndex != 0 && myIndex != NSNotFound ) {
        return [self.navigationController.viewControllers objectAtIndex:myIndex-1];
    } else {
        return nil;
    }
}

18、保存UIImage到本地
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *filePath = [[paths objectAtIndex:0] stringByAppendingPathComponent:@"Image.png"];
[UIImagePNGRepresentation(image) writeToFile:filePath atomically:YES];

19、键盘上方增加工具栏
UIToolbar *keyboardDoneButtonView = [[UIToolbar alloc] init];
[keyboardDoneButtonView sizeToFit];
UIBarButtonItem *doneButton = [[UIBarButtonItem alloc] initWithTitle:@"Done"
                                                               style:UIBarButtonItemStyleBordered target:self
                                                              action:@selector(doneClicked:)];
[keyboardDoneButtonView setItems:[NSArray arrayWithObjects:doneButton, nil]];
txtField.inputAccessoryView = keyboardDoneButtonView;

20、在image上绘制文字并生成新的image
    UIFont *font = [UIFont boldSystemFontOfSize:12];
    UIGraphicsBeginImageContext(image.size);
    [image drawInRect:CGRectMake(0,0,image.size.width,image.size.height)];
    CGRect rect = CGRectMake(point.x, point.y, image.size.width, image.size.height);
    [[UIColor whiteColor] set];
    [text drawInRect:CGRectIntegral(rect) withFont:font]; 
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

21、判断一个view是否为另一个view的子视图
// 如果myView是self.view本身，也会返回yes
BOOL isSubView = [myView isDescendantOfView:self.view];

22、判断一个字符串是否包含另一个字符串
// 方法一、这种方法只适用于iOS8之后，如果是配iOS8之前用方法二
if ([str containsString:otherStr]) NSLog(@"包含");

// 方法二
NSRange range = [str rangeOfString:otherStr];
if (range.location != NSNotFound) NSLog(@"包含");

23、判断某一行的cell是否已经显示
CGRect cellRect = [tableView rectForRowAtIndexPath:indexPath];
BOOL completelyVisible = CGRectContainsRect(tableView.bounds, cellRect);

24、让导航控制器pop回指定的控制器
NSMutableArray *allViewControllers = [NSMutableArray arrayWithArray:[self.navigationController viewControllers]];
for (UIViewController *aViewController in allViewControllers) {
    if ([aViewController isKindOfClass:[RequiredViewController class]]) {
        [self.navigationController popToViewController:aViewController animated:NO];
        break;
    }
}

25、获取屏幕方向
UIInterfaceOrientation orientation = [UIApplication sharedApplication].statusBarOrientation;

if(orientation == 0) //Default orientation 
    //默认
else if(orientation == UIInterfaceOrientationPortrait)
    //竖屏
else if(orientation == UIInterfaceOrientationLandscapeLeft)
    // 左横屏
else if(orientation == UIInterfaceOrientationLandscapeRight)
    //右横屏

26、UIWebView添加单击手势不响应
UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(webViewClick)];
        tap.delegate = self;
        [_webView addGestureRecognizer:tap];

// 因为webView本身有一个单击手势，所以再添加会造成手势冲突，从而不响应。需要绑定手势代理，并实现下边的代理方法
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer{
    return YES;
}

27、获取手机RAM容量

// 需要导入#import
mach_port_t host_port;
    mach_msg_type_number_t host_size;
    vm_size_t pagesize;

    host_port = mach_host_self();
    host_size = sizeof(vm_statistics_data_t) / sizeof(integer_t);
    host_page_size(host_port, &pagesize);

    vm_statistics_data_t vm_stat;

    if (host_statistics(host_port, HOST_VM_INFO, (host_info_t)&vm_stat, &host_size) != KERN_SUCCESS) {
        NSLog(@"Failed to fetch vm statistics");
    }

    /* Stats in bytes */
    natural_t mem_used = (vm_stat.active_count +
                          vm_stat.inactive_count +
                          vm_stat.wire_count) * pagesize;
    natural_t mem_free = vm_stat.free_count * pagesize;
    natural_t mem_total = mem_used + mem_free;
    NSLog(@"已用: %u 可用: %u 总共: %u", mem_used, mem_free, mem_total);

28、地图上两个点之间的实际距离

// 需要导入#import   位置A、B
CLLocation *locA = [[CLLocation alloc] initWithLatitude:34 longitude:113];
CLLocation *locB = [[CLLocation alloc] initWithLatitude:31.05 longitude:121.76];
// CLLocationDistance求出的单位为米
CLLocationDistance distance = [locA distanceFromLocation:locB];

29、在应用中打开设置的某个界面

// 打开设置->通用
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"prefs:root=General"]];

// 以下是设置其他界面
prefs:root=General&path=About
prefs:root=General&path=ACCESSIBILITY
prefs:root=AIRPLANE_MODE
prefs:root=General&path=AUTOLOCK
prefs:root=General&path=USAGE/CELLULAR_USAGE
prefs:root=Brightness
prefs:root=Bluetooth
prefs:root=General&path=DATE_AND_TIME
prefs:root=FACETIME
prefs:root=General
prefs:root=General&path=Keyboard
prefs:root=CASTLE
prefs:root=CASTLE&path=STORAGE_AND_BACKUP
prefs:root=General&path=INTERNATIONAL
prefs:root=LOCATION_SERVICES
prefs:root=ACCOUNT_SETTINGS
prefs:root=MUSIC
prefs:root=MUSIC&path=EQ
prefs:root=MUSIC&path=VolumeLimit
prefs:root=General&path=Network
prefs:root=NIKE_PLUS_IPOD
prefs:root=NOTES
prefs:root=NOTIFICATIONS_ID
prefs:root=Phone
prefs:root=Photos
prefs:root=General&path=ManagedConfigurationList
prefs:root=General&path=Reset
prefs:root=Sounds&path=Ringtone
prefs:root=Safari
prefs:root=General&path=Assistant
prefs:root=Sounds
prefs:root=General&path=SOFTWARE_UPDATE_LINK
prefs:root=STORE
prefs:root=TWITTER
prefs:root=FACEBOOK
prefs:root=General&path=USAGE prefs:root=VIDEO
prefs:root=General&path=Network/VPN
prefs:root=Wallpaper
prefs:root=WIFI
prefs:root=INTERNET_TETHERING
prefs:root=Phone&path=Blocked
prefs:root=DO_NOT_DISTURB

30、监听scrollView是否滚动到了顶部／底部

-(void)scrollViewDidScroll: (UIScrollView*)scrollView
{
    float scrollViewHeight = scrollView.frame.size.height;
    float scrollContentSizeHeight = scrollView.contentSize.height;
    float scrollOffset = scrollView.contentOffset.y;

    if (scrollOffset == 0)
    {
        // 滚动到了顶部
    }
    else if (scrollOffset + scrollViewHeight == scrollContentSizeHeight)
    {
        // 滚动到了底部
    }
}

31、从导航控制器中删除某个控制器

// 方法一、知道这个控制器所处的导航控制器下标
NSMutableArray *navigationArray = [[NSMutableArray alloc] initWithArray: self.navigationController.viewControllers];
[navigationArray removeObjectAtIndex: 2]; 
self.navigationController.viewControllers = navigationArray;

// 方法二、知道具体是哪个控制器
NSArray* tempVCA = [self.navigationController viewControllers];
for(UIViewController *tempVC in tempVCA)
{
    if([tempVC isKindOfClass:[urViewControllerClass class]])
    {
        [tempVC removeFromParentViewController];
    }
}

32、触摸事件类型

UIControlEventTouchCancel 取消控件当前触发的事件
UIControlEventTouchDown 点按下去的事件
UIControlEventTouchDownRepeat 重复的触动事件
UIControlEventTouchDragEnter 手指被拖动到控件的边界的事件
UIControlEventTouchDragExit 一个手指从控件内拖到外界的事件
UIControlEventTouchDragInside 手指在控件的边界内拖动的事件
UIControlEventTouchDragOutside 手指在控件边界之外被拖动的事件
UIControlEventTouchUpInside 手指处于控制范围内的触摸事件
UIControlEventTouchUpOutside 手指超出控制范围的控制中的触摸事件

33、比较两个UIImage是否相等
- (BOOL)image:(UIImage *)image1 isEqualTo:(UIImage *)image2
{
    NSData *data1 = UIImagePNGRepresentation(image1);
    NSData *data2 = UIImagePNGRepresentation(image2);

    return [data1 isEqual:data2];
}

34、代码方式调整屏幕亮度
// brightness属性值在0-1之间，0代表最小亮度，1代表最大亮度
[[UIScreen mainScreen] setBrightness:0.5];

35、根据经纬度获取城市等信息

// 创建经纬度
CLLocation *location = [[CLLocation alloc] initWithLatitude:latitude longitude:longitude];
//创建一个译码器
CLGeocoder *cLGeocoder = [[CLGeocoder alloc] init];
[cLGeocoder reverseGeocodeLocation:userLocation completionHandler:^(NSArray *placemarks, NSError *error) {
    CLPlacemark *place = [placemarks objectAtIndex:0];
    // 位置名
    NSLog(@"name,%@",place.name);
    // 街道
    NSLog(@"thoroughfare,%@",place.thoroughfare);
    // 子街道
    NSLog(@"subThoroughfare,%@",place.subThoroughfare);
    // 市
    NSLog(@"locality,%@",place.locality);
    // 区
    NSLog(@"subLocality,%@",place.subLocality); 
    // 国家
    NSLog(@"country,%@",place.country);
    }
}];

36、如何防止添加多个NSNotification观察者？
// 解决方案就是添加观察者之前先移除下这个观察者
[[NSNotificationCenter defaultCenter] removeObserver:observer name:name object:object];
[[NSNotificationCenter defaultCenter] addObserver:observer selector:selector name:name object:object];

37、处理字符串，使其首字母大写
NSString *str = @"abcdefghijklmn";
 NSString *resultStr;
if (str && str.length > 0) {
     resultStr = [str stringByReplacingCharactersInRange:NSMakeRange(0,1) withString:[[str substringToIndex:1] capitalizedString]];
}
NSLog(@"%@", resultStr);

38、获取字符串中的数字
- (NSString *)getNumberFromStr:(NSString *)str
{
    NSCharacterSet *nonDigitCharacterSet = [[NSCharacterSet decimalDigitCharacterSet] invertedSet];
    return [[str componentsSeparatedByCharactersInSet:nonDigitCharacterSet] componentsJoinedByString:@""];
}

39、为UIView的某个方向添加边框
- (void)wzb_addBorder:(WZBBorderDirectionType)direction color:(UIColor *)color width:(CGFloat)width
{
    CALayer *border = [CALayer layer];
    border.backgroundColor = color.CGColor;
    switch (direction) {
        case WZBBorderDirectionTop:
        {
            border.frame = CGRectMake(0.0f, 0.0f, self.bounds.size.width, width);
        }
            break;
        case WZBBorderDirectionLeft:
        {
            border.frame = CGRectMake(0.0f, 0.0f, width, self.bounds.size.height);
        }
            break;
        case WZBBorderDirectionBottom:
        {
            border.frame = CGRectMake(0.0f, self.bounds.size.height - width, self.bounds.size.width, width);
        }
            break;
        case WZBBorderDirectionRight:
        {
            border.frame = CGRectMake(self.bounds.size.width - width, 0, width, self.bounds.size.height);
        }
            break;
        default:
            break;
    }
    [self.layer addSublayer:border];
}

40、自动搜索功能，用户连续输入的时候不搜索，用户停止输入的时候自动搜索(我这里设置的是0.5s，可根据需求更改)
// 输入框文字改变的时候调用
-(void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText{
    // 先取消调用搜索方法
    [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(searchNewResult) object:nil];
    // 0.5秒后调用搜索方法
    [self performSelector:@selector(searchNewResult) withObject:nil afterDelay:0.5];
}

41、修改UISearchBar的占位文字颜色
// 方法一（推荐使用）
UITextField *searchField = [searchBar valueForKey:@"_searchField"];
[searchField setValue:[UIColor blueColor] forKeyPath:@"_placeholderLabel.textColor"];

// 方法二（已过期）
[[UILabel appearanceWhenContainedIn:[UISearchBar class], nil] setTextColor:[UIColor redColor]];

 // 方法三（已过期）
NSDictionary *placeholderAttributes = @{NSForegroundColorAttributeName : [UIColor redColor], NSFontAttributeName : [UIFont fontWithName:@"HelveticaNeue" size:15],};
NSAttributedString *attributedPlaceholder = [[NSAttributedString alloc] initWithString:searchBar.placeholder attributes:placeholderAttributes];
[[UITextField appearanceWhenContainedIn:[UISearchBar class], nil] setAttributedPlaceholder:attributedPlaceholder];

42、动画执行removeFromSuperview
[UIView animateWithDuration:0.2
                animations:^{
                     view.alpha = 0.0f;
                } completion:^(BOOL finished){
                    [view removeFromSuperview];
                }];

43、修改image颜色
UIImage *image = [UIImage imageNamed:@"test"];
imageView.image = [image imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];
CGRect rect = CGRectMake(0, 0, image.size.width, image.size.height);
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextClipToMask(context, rect, image.CGImage);
CGContextSetFillColorWithColor(context, [[UIColor redColor] CGColor]);
CGContextFillRect(context, rect);
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

UIImage *flippedImage = [UIImage imageWithCGImage:img.CGImage scale:1.0 orientation: UIImageOrientationDownMirrored];
imageView.image = flippedImage;

44、利用runtime获取一个类所有属性
- (NSArray *)allPropertyNames:(Class)aClass
{
    unsigned count;
    objc_property_t *properties = class_copyPropertyList(aClass, &count);

    NSMutableArray *rv = [NSMutableArray array];

    unsigned i;
    for (i = 0; i < count; i++)
    {
        objc_property_t property = properties[i];
        NSString *name = [NSString stringWithUTF8String:property_getName(property)];
        [rv addObject:name];
    }

    free(properties);

    return rv;
}

45、让push跳转动画像modal跳转动画那样效果(从下往上推上来)

- (void)push
{
TestViewController *vc = [[TestViewController alloc] init];
    vc.view.backgroundColor = [UIColor redColor];
    CATransition* transition = [CATransition animation];
    transition.duration = 0.4f;
    transition.type = kCATransitionMoveIn;
    transition.subtype = kCATransitionFromTop;
    [self.navigationController.view.layer addAnimation:transition forKey:kCATransition];
    [self.navigationController pushViewController:vc animated:NO];
}

- (void)pop
{
CATransition* transition = [CATransition animation];
    transition.duration = 0.4f;
    transition.type = kCATransitionReveal;
    transition.subtype = kCATransitionFromBottom;
    [self.navigationController.view.layer addAnimation:transition forKey:kCATransition];
    [self.navigationController popViewControllerAnimated:NO];
}