iOS開發的一些奇巧淫技

iOS的一些小技巧

TableView不顯示沒內容的Cell怎麼辦?

相似這種,我不想讓下面那些空的顯示.

很簡單.

self.tableView.tableFooterView = [[UIView alloc] init];
試過的都說好.

加完這句以後就變成了這樣.

自定義了leftBarbuttonItem左滑返回手勢失效了怎麼辦?

    self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc]
                                         initWithImage:img
                                         style:UIBarButtonItemStylePlain
                                         target:self
                                         action:@selector(onBack:)];
self.navigationController.interactivePopGestureRecognizer.delegate = (id<UIGestureRecognizerDelegate>)self;

ScrollView莫名其妙不能在viewController劃到頂怎麼辦?

self.automaticallyAdjustsScrollViewInsets = NO;

鍵盤事件寫的好煩躁,都想摔鍵盤了,怎麼辦?

1. 買個結實的鍵盤.

2. 使用IQKeyboardManager(github上可搜索),用完以後腰也不疼了,腿也不酸了.

爲何個人app總是不流暢,到底哪裏出了問題?

如圖

這個神器叫作:KMCGeigerCounter
快去github搬運吧.

怎麼在不新建一個Cell的狀況下調整separaLine的位置?

_myTableView.separatorInset = UIEdgeInsetsMake(0, 100, 0, 0);

怎麼點擊self.view就讓鍵盤收起,須要添加一個tapGestures麼?

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
   [self.view endEditing:YES];
}

怎麼給每一個ViewController設定默認的背景圖片?

使用基類啊,少年.

想在代碼裏改在xib裏添加的layoutAttributes,可是怎麼用代碼找啊?

像拉button同樣的拉你的約束.nslayoutattribute也是能夠拉線的.

怎麼像safari同樣滑動的時候隱藏navigationbar?

navigationController.hidesBarsOnSwipe = Yes

導航條返回鍵帶的title太討厭了,怎麼讓它消失!

[[UIBarButtonItem appearance] setBackButtonTitlePositionAdjustment:UIOffsetMake(0, -60)
                                                     forBarMetrics:UIBarMetricsDefault];

CoreData用起來好煩,語法又臭又長,怎麼辦?

MagicalRecord

CollectionView 怎麼實現tableview那種懸停的header?

CSStickyHeaderFlowLayout

能不能只用一個pan手勢來代替UISwipegesture的各個方向?

- (void)pan:(UIPanGestureRecognizer *)sender
{

typedef NS_ENUM(NSUInteger, UIPanGestureRecognizerDirection) {
    UIPanGestureRecognizerDirectionUndefined,
    UIPanGestureRecognizerDirectionUp,
    UIPanGestureRecognizerDirectionDown,
    UIPanGestureRecognizerDirectionLeft,
    UIPanGestureRecognizerDirectionRight
};

static UIPanGestureRecognizerDirection direction = UIPanGestureRecognizerDirectionUndefined;

switch (sender.state) {

    case UIGestureRecognizerStateBegan: {

        if (direction == UIPanGestureRecognizerDirectionUndefined) {

            CGPoint velocity = [sender velocityInView:recognizer.view];

            BOOL isVerticalGesture = fabs(velocity.y) > fabs(velocity.x);

            if (isVerticalGesture) {
                if (velocity.y > 0) {
                    direction = UIPanGestureRecognizerDirectionDown;
                } else {
                    direction = UIPanGestureRecognizerDirectionUp;
                }
            }

            else {
                if (velocity.x > 0) {
                    direction = UIPanGestureRecognizerDirectionRight;
                } else {
                    direction = UIPanGestureRecognizerDirectionLeft;
                }
            }
        }

        break;
    }

    case UIGestureRecognizerStateChanged: {
        switch (direction) {
            case UIPanGestureRecognizerDirectionUp: {
                [self handleUpwardsGesture:sender];
                break;
            }
            case UIPanGestureRecognizerDirectionDown: {
                [self handleDownwardsGesture:sender];
                break;
            }
            case UIPanGestureRecognizerDirectionLeft: {
                [self handleLeftGesture:sender];
                break;
            }
            case UIPanGestureRecognizerDirectionRight: {
                [self handleRightGesture:sender];
                break;
            }
            default: {
                break;
            }
        }
        break;
    }

    case UIGestureRecognizerStateEnded: {
        direction = UIPanGestureRecognizerDirectionUndefined;   
        break;
    }

    default:
        break;
}

}

拉伸圖片的時候怎麼才能讓圖片不變形？

1. UIImage *image = [[UIImage imageNamed:@"xxx"] stretchableImageWithLeftCapWidth:10 topCapHeight:10];
   (剛纔有人提醒這個已經deprecated了哈,如今的方法叫resizableImageWithCapInsets).

2. 
   

怎麼播放GIF的時候這麼卡，有沒有好點的庫？

FlipBoard出品的太適合你了。https://github.com/Flipboard/FLAnimatedImage

怎麼一句話添加上拉刷新？

https://github.com/samvermette/SVPullToRefresh

[tableView addPullToRefreshWithActionHandler:^{
// prepend data to dataSource, insert cells at top of table view
// call [tableView.pullToRefreshView stopAnimating] when done
} position:SVPullToRefreshPositionBottom];

怎麼把tableview裏cell的小對勾的顏色改爲別的顏色？

_mTableView.tintColor = [UIColor redColor];

原本個人statusbar是lightcontent的，結果用UIImagePickerController會致使個人statusbar的樣式變成黑色，怎麼辦？

- (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated {    [[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent]; }

怎麼把個人navigationbar弄成透明的而不是帶模糊的效果？

[self.navigationBar setBackgroundImage:[UIImage new]                         forBarMetrics:UIBarMetricsDefault]; self.navigationBar.shadowImage = [UIImage new]; self.navigationBar.translucent = YES;

怎麼改變uitextfield placeholder的顏色和位置？

繼承uitextfield，重寫這個方法
- (void) drawPlaceholderInRect:(CGRect)rect {    [[UIColor blueColor] setFill];    [self.placeholder drawInRect:rect withFont:self.font lineBreakMode:UILineBreakModeTailTruncation alignment:self.textAlignment]; }