iOS开发常用代码总结(三)

41、适配iOS11

if (@available(ios 11.0,*)) {        UIScrollView.appearance.contentInsetAdjustmentBehavior = UIScrollViewContentInsetAdjustmentNever;        UITableView.appearance.estimatedRowHeight = 0;        UITableView.appearance.estimatedSectionFooterHeight = 0;        UITableView.appearance.estimatedSectionHeaderHeight = 0;    }

42、查看系统所有字体

// 打印字体for (id familyName in [UIFont familyNames]) {    NSLog(@"%@", familyName);    for (id fontName in [UIFont fontNamesForFamilyName:familyName]) NSLog(@"  %@", fontName);}

43、获取随机数

NSInteger i = arc4random();

44、获取随机数小数(0-1之间)

#define ARC4RANDOM_MAX      0x100000000double val = ((double)arc4random() / ARC4RANDOM_MAX);

45、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];

46、键盘栏上方增加工具栏

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;

47、UICollectionView自动滚动到某行

// 重写viewDidLayoutSubviews方法-(void)viewDidLayoutSubviews {   [super viewDidLayoutSubviews];   [self.collectionView scrollToItemAtIndexPath:indexPath atScrollPosition:UICollectionViewScrollPositionCenteredVertically animated:NO];}

48、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];    }}

49、判断字典中是否包含某个key值

if ([dic objectForKey:@"yourKey"]) {    NSLog(@"有这个值");} else {    NSLog(@"没有这个值");}

50、选中textView所有文本

[self.textView setSelectedTextRange:[self.textView textRangeFromPosition:self.textView.beginningOfDocument toPosition:self.textView.endOfDocument]]

51、隐藏UITextView/UITextField光标

textField.tintColor = [UIColor clearColor];

52、当UITextView/UITextField中没有文字时，禁用回车键

textField.enablesReturnKeyAutomatically = YES;

53、获取随机UUID

    NSString *result;    if([[[UIDevice currentDevice] systemVersion] floatValue] > 6.0)    {       result = [[NSUUID UUID] UUIDString];    }    else    {        CFUUIDRef uuidRef = CFUUIDCreate(NULL);        CFStringRef uuid = CFUUIDCreateString(NULL, uuidRef);        CFRelease(uuidRef);        result = (__bridge_transfer NSString *)uuid;    }

54、修改UISearBar内部背景颜色

    UITextField *textField = [_searchBar valueForKey:@"_searchField"];    textField.backgroundColor = [UIColor redColor];

55、UITextView滚动到顶部

    // 方法一    [self.textView scrollRangeToVisible:NSMakeRange(0, 0)];    // 方法二    [self.textView setContentOffset:CGPointZero animated:YES];

56、通知监听APP生命周期

    UIApplicationDidEnterBackgroundNotification 应用程序进入后台    UIApplicationWillEnterForegroundNotification 应用程序将要进入前台    UIApplicationDidFinishLaunchingNotification 应用程序完成启动    UIApplicationDidFinishLaunchingNotification 应用程序由挂起变的活跃    UIApplicationWillResignActiveNotification 应用程序挂起(有电话进来或者锁屏)    UIApplicationDidReceiveMemoryWarningNotification 应用程序收到内存警告    UIApplicationDidReceiveMemoryWarningNotification 应用程序终止(后台杀死、手机关机等)    UIApplicationSignificantTimeChangeNotification 当有重大时间改变(凌晨0点，设备时间被修改，时区改变等)    UIApplicationWillChangeStatusBarOrientationNotification 设备方向将要改变    UIApplicationDidChangeStatusBarOrientationNotification 设备方向改变    UIApplicationWillChangeStatusBarFrameNotification 设备状态栏frame将要改变    UIApplicationDidChangeStatusBarFrameNotification 设备状态栏frame改变    UIApplicationBackgroundRefreshStatusDidChangeNotification 应用程序在后台下载内容的状态发生变化    UIApplicationProtectedDataWillBecomeUnavailable 本地受保护的文件被锁定,无法访问    UIApplicationProtectedDataWillBecomeUnavailable 本地受保护的文件可用了

57、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

58、设置UITextField光标位置

    // textField需要设置的textField，index要设置的光标位置- (void)cursorLocation:(UITextField *)textField index:(NSInteger)index{    NSRange range = NSMakeRange(index, 0);    UITextPosition *start = [textField positionFromPosition:[textField beginningOfDocument] offset:range.location];    UITextPosition *end = [textField positionFromPosition:start offset:range.length];    [textField setSelectedTextRange:[textField textRangeFromPosition:start toPosition:end]];}

59、去除webView底部黑色

    [webView setBackgroundColor:[UIColor clearColor]];    [webView setOpaque:NO];    for (UIView *v1 in [webView subviews])    {        if ([v1 isKindOfClass:[UIScrollView class]])        {            for (UIView *v2 in v1.subviews)            {                if ([v2 isKindOfClass:[UIImageView class]])                {                    v2.hidden = YES;                }            }        }    }

60、解决当UIScrollView上有UIButton的时候，触摸到button滑动不了的问题

// 子类化UIScrollView，并重写以下方法- (instancetype)initWithFrame:(CGRect)frame {    if (self = [super initWithFrame:frame]) {        self.delaysContentTouches = NO;    }    return self;}- (BOOL)touchesShouldCancelInContentView:(UIView *)view {    if ([view isKindOfClass:UIButton.class]) {        return YES;    }    return [super touchesShouldCancelInContentView:view];}