iOS-开发技巧

Posted 2020-06-19

1. TableView不显示没内容的Cell怎么办？ 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，

2. 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 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;
}
} 

1. 拉伸图片的时候怎么才能让图片不变形？ 方法一： UIImage *image = [[UIImage imageNamed:@"xxx"] stretchableImageWithLeftCapWidth:10 topCapHeight:10];
   注：有开发者提醒这个已经弃用，现在的方法叫resizableImageWithCapInsets。

2. 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。

3. 怎么一句话添加上拉刷新？ 使用SVPullToRefresh库： [tableView addPullToRefreshWithActionHandler:^{
   // prepend data to dataSource, insert cells at top of table view
   // call [tableView.pullToRefreshView stopAnimating] when done
   } position:SVPullToRefreshPositionBottom]; 

4. 怎么把tableview里Cell的小对勾颜色改成别的颜色？ _mTableView.tintColor = [UIColor redColor]; 

5. 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];
  } 

1. 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; 

1. 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];
     } 

22.在使用SB的时候对UIimageView 设置为圆行（圆角） 选中imageView