22 amazing technologies developed by iOS, ios22

22 amazing technologies developed by iOS, ios22

I have summed up 22 tips for iOS development based on my own practical development experience. In a very happy tone, I can easily solve all kinds of hard-hitting problems encountered during the development process.

　　1. What should I do if no Cell is displayed in TableView?

Similar to Figure 1, I don't want to display the empty ones below. It's easy to add "self. tableView. tableFooterView = [[UIView alloc] init];". After trying this sentence, it will look like Figure 2.

　　2. The custom leftBarbuttonItem left slide returned gesture is invalid. What should I do?

123456

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

　　3. Why can't ScrollView be switched to the top of viewController?

1	self.automaticallyAdjustsScrollViewInsets = NO;

　　4. What should I do if I want to throw my keyboard when writing a keyboard event?

• Buy a strong keyboard;
• IQKeyboardManager (available on GitHub) does not hurt your waist and legs after you use it.

　　5. Why is there a problem with my apps?

　　

This is called KMCGeigerCounter. Go to GitHub and move it.

　　6. How can I adjust the separaLine position without creating a Cell?

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

　　7. How can I click self. view to collapse the keyboard? Do I need to add a tapGestures?

1234	- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{   [self.view endEditing:YES];}

　　8. How to set the Default background image for each ViewController?

Use the base class.

　　9. I want to change the layoutAttributes added in xib in the code, but how can I find it using the code?

Nslayoutattribute can also be used to pull your constraints like a Button.

　　10. How can I hide the navigationbar when sliding like Safari?

1	navigationController.hidesBarsOnSwipe = Yes

　　11. The title of the navigation bar's return key is so annoying. How can I make it disappear?

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

　　12. CoreData is so annoying to use. What should I do if the syntax is smelly and long?

MagicRecord

　　13. How does CollectionView implement the hovering header of tableview?

CSStickyHeaderFlowLayout

　　14. Can I use only one pan gesture to replace all directions of UISwipegesture?

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- (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;}}

　　15. How can I make the image not deformed when stretching the image?

Method 1:

1	UIImage *image = [[UIImage imageNamed:@"xxx"] stretchableImageWithLeftCapWidth:10 topCapHeight:10];

Note: A developer reminds me that this application has been disabled. The current method is resizableImageWithCapInsets.

Method 2,

　　16. Why is there a better library when playing GIF videos?

FLAnimatedImage produced by FlipBoard is very suitable for you.

　　17. How can I add pull-up refresh in one sentence?

Use the SVPullToRefresh Library:

1234	[tableView addPullToRefreshWithActionHandler:^{// prepend data to dataSource, insert cells at top of table view// call [tableView.pullToRefreshView stopAnimating] when done} position:SVPullToRefreshPositionBottom];

　　18. How can I change the Cell color in tableview to another color?

1	_mTableView.tintColor = [UIColor redColor];

　　19. Originally, my statusbar was lightcontent. Using UIImagePickerController will make my statusbar style black. What should I do?

1234	- (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated{    [[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent];}

　　20. How can I make my navigationbar transparent instead of blurred?

1234	[self.navigationBar setBackgroundImage:[UIImage new]                         forBarMetrics:UIBarMetricsDefault];self.navigationBar.shadowImage = [UIImage new];self.navigationBar.translucent = YES;

　　21. How can I change the color and position of uitextfield placeholder?

Inherit uitextfield and override this method:

1234	- (void) drawPlaceholderInRect:(CGRect)rect {    [[UIColor blueColor] setFill];    [self.placeholder drawInRect:rect withFont:self.font lineBreakMode:UILineBreakModeTailTruncation alignment:self.textAlignment];}

　　22. Why do you know so many strange tricks?

Click Stack Overflow!