http://www.cnblogs.com/xiaochao12345/p/4312407.html
本文作者@叶孤城___，他结合自身的实践开发经验总结出了22个iOS开发的小技巧，以非常欢乐的语调轻松解决开发过程中所遇到的各种苦逼难题，光读着便已忍俊不禁。
1. TableView不显示没内容的Cell怎么办？
类似于图1，我不想让下面的那些空显示。很简单，添加“self.tableView.tableFooterView = [[UIView alloc] init];”试过都说好，加完这句之后就变成了图2的样子。
2. 自定义了leftBarbuttonItem左滑返回手势失效了怎么办？
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self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc]
initWithImage:img
style:UIBarButtonItemStylePlain
target:self
action:@selector(onBack:)];
self.navigationController.interactivePopGestureRecognizer.delegate = (id<UIGestureRecognizerDelegate>)self;
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3. ScrollView莫名其妙不能在viewController划到顶怎么办？
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self.automaticallyAdjustsScrollViewInsets = NO;
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4. 键盘事件写得好烦躁，都想摔键盘了怎么办？
- 买个结实的键盘；
- 使用IQKeyboardManager（GitHub上可搜索），用完之后腰也不疼了，腿也不酸了。
5. 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上搬运吧。
6. 怎么在不新建一个Cell的情况下调整separaLine的位置？
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_myTableView.separatorInset = UIEdgeInsetsMake(0, 100, 0, 0);
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7. 怎么点击self.view就让键盘收起，需要添加一个tapGestures么？
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- (
void
)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
[self.view endEditing:YES];
}
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8. 怎么给每个ViewController设定默认的背景图片？
使用基类啊，少年。
9. 想在代码里改在xib里添加的layoutAttributes，但该怎么用代码找？
像拉Button一样地拉你的约束，nslayoutattribute也是可以拉线的。
10. 怎么像Safari一样滑动的时候隐藏navigationbar？
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navigationController.hidesBarsOnSwipe = Yes
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11. 导航条返回键带的title太讨厌了，怎么让它消失？
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[[UIBarButtonItem <span id=
"3_nwp"
style=
"width: auto; height: auto; float: none;"
><a id=
"3_nwl"
href=
"http://cpro.baidu.com/cpro/ui/uijs.php?c=news&cf=1001&ch=0&di=128&fv=11&jk=daa32d9bb1e0b2b5&k=app&k0=app&kdi0=0&luki=3&n=10&p=baidu&q=06011078_cpr&rb=0&rs=1&seller_id=1&sid=b5b2e0b19b2da3da&ssp2=1&stid=0&t=tpclicked3_hc&tu=u1922429&u=http%3A%2F%2Fwww%2Eadmin10000%2Ecom%2Fdocument%2F5765%2Ehtml&urlid=0"
target=
"_blank"
mpid=
"3"
style=
"text-decoration: none;"
><span style=
"color:#0000ff;font-size:14px;width:auto;height:auto;float:none;"
>app</span></a></span>earance] setBackButtonTitlePositionAdjustment:UIOffsetMake(0, -60)
forBarMetrics:UIBarMetricsDefault];
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12. CoreData用起来好烦，语法又臭又长怎么办？
MagicRecord
13. CollectionView怎么实现tableview那种悬停的header？
CSStickyHeaderFlowLayout
14. 能不能只用一个pan手势来代替UISwipegesture的各个方向？
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- (
void
)pan:(UIPanGestureRecognizer *)sender
{
typedef
NS_ENUM(NSUInteger, UIPanGestureRecognizerDirection) {
UIPanGestureRecognizerDirectionUndefined,
UIPanGestureRecognizerDirectionUp,
UIPanGestureRecognizerDirectionDown,
UIPanGestureRecognizerDirectionLeft,
UIPanGestureRecognizerDirectionRight
};
static
UIPanGestureRecognizerDirection direction = UIPanGestureRecognizerDirectionUndefined;
<span id=
"1_nwp"
style=
"width: auto; height: auto; float: none;"
><a id=
"1_nwl"
href=
"http://cpro.baidu.com/cpro/ui/uijs.php?c=news&cf=1001&ch=0&di=128&fv=11&jk=daa32d9bb1e0b2b5&k=switch&k0=switch&kdi0=0&luki=4&n=10&p=baidu&q=06011078_cpr&rb=0&rs=1&seller_id=1&sid=b5b2e0b19b2da3da&ssp2=1&stid=0&t=tpclicked3_hc&tu=u1922429&u=http%3A%2F%2Fwww%2Eadmin10000%2Ecom%2Fdocument%2F5765%2Ehtml&urlid=0"
target=
"_blank"
mpid=
"1"
style=
"text-decoration: none;"
><span style=
"color:#0000ff;font-size:14px;width:auto;height:auto;float:none;"
>
switch
</span></a></span> (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: {
<span id=
"2_nwp"
style=
"width: auto; height: auto; float: none;"
><a id=
"2_nwl"
href=
"http://cpro.baidu.com/cpro/ui/uijs.php?c=news&cf=1001&ch=0&di=128&fv=11&jk=daa32d9bb1e0b2b5&k=switch&k0=switch&kdi0=0&luki=4&n=10&p=baidu&q=06011078_cpr&rb=0&rs=1&seller_id=1&sid=b5b2e0b19b2da3da&ssp2=1&stid=0&t=tpclicked3_hc&tu=u1922429&u=http%3A%2F%2Fwww%2Eadmin10000%2Ecom%2Fdocument%2F5765%2Ehtml&urlid=0"
target=
"_blank"
mpid=
"2"
style=
"text-decoration: none;"
><span style=
"color:#0000ff;font-size:14px;width:auto;height:auto;float:none;"
>
switch
</span></a></span> (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
;
}
}
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15. 拉伸图片的时候怎么才能让图片不变形？
方法一：
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UIImage *image = [[UIImage imageNamed:@
"xxx"
] stretchableImageWithLeftCapWidth:10 topCapHeight:10];
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注：有开发者提醒这个已经弃用，现在的方法叫resizableImageWithCapInsets。
方法二，如图：
16. 怎么播放GIF的时候这么卡，有没有好点的库？
FlipBoard出品的FLAnimatedImage太适合你了。
17. 怎么一句话添加上拉刷新？
使用SVPullToRefresh库：
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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];
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18. 怎么把tableview里Cell的小对勾颜色改成别的颜色？
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_mTableView.tintColor = [UIColor redColor];
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19. 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？
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- (
void
)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(
BOOL
)animated
{
[[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent];
}
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20. 怎么把我的navigationbar弄成透明的而不是带模糊的效果？
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[self.navigationBar setBackgroundImage:[UIImage
new
]
forBarMetrics:UIBarMetricsDefault];
self.navigationBar.shadowImage = [UIImage
new
];
self.navigationBar.translucent = YES;
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21. 怎么改变uitextfield placeholder的颜色和位置？
继承uitextfield，重写这个方法：
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- (
void
) drawPlaceholderInRect:(CGRect)rect {
[[UIColor blueColor] setFill];
[self.placeholder drawInRect:rect withFont:self.font lineBreakMode:UILineBreakModeTailTruncation alignment:self.textAlignment];
}
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22. 你为什么知道这么多奇怪的花招？
去Stack Overflow刷问题啊，少年！
