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最新推荐文章于 2020-02-03 21:50:49 发布

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最新推荐文章于 2020-02-03 21:50:49 发布

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本文汇总了iOS开发中遇到的各种常见问题及其解决方案，包括TableView优化、ScrollView问题解决、手势识别改进等，为开发者提供实用的技巧。

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TableView不显示没内容的Cell怎么办?

类似这种,我不想让下面那些空的显示.

这里写图片描述
很简单

self.tableView.tableFooterView = [[UIView alloc] init];

试过的都说好.

加完这句之后就变成了这样.

这里写图片描述

自定义了leftBarbuttonItem左滑返回手势失效了怎么办?

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划到顶怎么办?

self.automaticallyAdjustsScrollViewInsets = NO;

键盘事件写的好烦躁,都想摔键盘了,怎么办?

使用IQKeyboardManager(github上可搜索)

为什么我的app老是不流畅,到底哪里出了问题?

KMCGeigerCounter,快去github搬运吧.

怎么在不新建一个Cell的情况下调整separaLine的位置?

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

怎么点击self.view就让键盘收起,需要添加一个tapGestures么?

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

怎么给每个ViewController设定默认的背景图片?

使用基类啊,少年。

怎么像safari一样滑动的时候隐藏navigationbar?

navigationController.hidesBarsOnSwipe = Yes

导航条返回键带的title太讨厌了,怎么让它消失!

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

CoreData用起来好烦,语法又臭又长,怎么办?

MagicRecord

CSStickyHeaderFlowLayou

能不能只用一个pan手势来代替UISwipegesture的各个方向?

- (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;
}

拉伸图片的时候怎么才能让图片不变形？

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

怎么播放GIF的时候这么卡，有没有好点的库?

FlipBoard出品的太适合你了：
https://github.com/Flipboard/FLAnimatedImage

怎么一句话添加上拉刷新？

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];

怎么把tableview里cell的小对勾的颜色改成别的颜色？

_mTableView.tintColor = [UIColor redColor];

本来我的statusbar是lightcontent的，结果用UIImagePickerController会导致我的statusbar的样式变成黑色，怎么办？

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

怎么把我的navigationbar弄成透明的而不是带模糊的效果？

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

怎么改变uitextfield placeholder的颜色和位置？

继承UITextField，重写这个方法

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

你为什么知道这么多奇怪的花招？

去stackoverflow刷问题啊，少年！