iOS开发的一些实用小技巧

iOS开发的一些实用小技巧

分类： iOS2015-01-04
11:57 2447人阅读 评论(3) 收藏 举报

iOS

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.



很简单.

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

试过的都说好.

加完这句之后就变成了这样.



自定义了leftBarbuttonItem左滑返回手势失效了怎么办?

[objc] view
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self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc]

initWithImage:img

style:UIBarButtonItemStylePlain

target:self

action:@selector(onBack:)];

self.navigationController.interactivePopGestureRecognizer.delegate = (id)self;

ScrollView莫名其妙不能在viewController划到顶怎么办?

[objc] view
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self.automaticallyAdjustsScrollViewInsets = NO;

键盘事件写的好烦躁,都想摔键盘了,怎么办?

1.买个结实的键盘.

2.使用IQKeyboardManager(github上可搜索),用完之后腰也不疼了,腿也不酸了.

为什么我的app老是不流畅,到底哪里出了问题?

如图



这个神器叫做: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?

[objc] view
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_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?

[objc] view
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- (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。

想在代码里改在xib里添加的layoutAttributes,但是怎么用代码找啊?

像拉button一样的拉你的约束.nslayoutattribute也是可以拉线的.

怎么像safari一样滑动的时候隐藏navigationbar?

[objc] view
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self.navigationController.hidesBarsOnSwipe = YES;

导航条返回键带的title太讨厌了,怎么让它消失!

[objc] view
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[[UIBarButtonItem appearance] setBackButtonTitlePositionAdjustment:UIOffsetMake(0, -60)

forBarMetrics:UIBarMetricsDefault];

CoreData用起来好烦,语法又臭又长,怎么办?

Magical Record https://github.com/magicalpanda/MagicalRecord

CollectionView 怎么实现tableview那种悬停的header?

CSStickyHeaderFlowLayout

能不能只用一个pan手势来代替UISwipegesture的各个方向?

[objc] view
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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;

}

}

拉伸图片的时候怎么才能让图片不变形？

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

2.



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

[objc] view
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[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？

[objc] view
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_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？

[objc] view
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- (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？

[objc] view
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[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

[objc] view
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- (void) drawPlaceholderInRect:(CGRect)rect {

[[UIColor blueColor] setFill];

[self.placeholder drawInRect:rect withFont:self.font lineBreakMode:UILineBreakModeTailTruncation alignment:self.textAlignment];

}