小代码合集

解决block中self的引用

__weak typeof(self) weakSelf = self

iOS获得屏幕大小

//宽度:
UIScreen mainScreen] bounds].size.width

//高度:
UIScreen mainScreen] bounds].size.height

//可以将屏幕大小定义成一个宏:
#define SCREEN_WIDTH ([[UIScreen mainScreen] bounds].size.width)

#define SCREEN_HEIGHT ([[UIScreen mainScreen] bounds].size.height)

延时执行可以尝试NSTimer方法

例子：UIAlertViewController自动消失

UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"提示" message:@"没有上一部了" preferredStyle:UIAlertControllerStyleAlert];

[self presentViewController:alert animated:NO completion:nil];

[NSTimer scheduledTimerWithTimeInterval:0.5 target:self selector:@selector(creatAlert:) userInfo:alert repeats:NO];

- (void)creatAlert:(NSTimer *)timer {

    UIAlertController *alert = [timer userInfo];

    [alert dismissViewControllerAnimated:YES completion:nil];

    alert = nil;

}

定制statusBar部分

-(UIStatusBarStyle)preferredStatusBarStyle

{

    return UIStatusBarStyleLightContent;

}

   NSString 和 NSNumber 

NSString *str = @"120".

NSNumberFormatter *numberFormatter = [[NSNumberFormatter alloc] init];

[numberFormatter setNumberStyle:NSNumberFormatterDecimalStyle];

NSNumber *numTemp = [numberFormatter numberFromString:str];

NSNumber *num = [NSNumber numberWithInt:2] ;

NSNumberFormatter *numberFormatter = [[NSNumberFormatter alloc] init];

NSString* str = [numberFormatter stringFromNumber:num];

UINavigationController先pop再push，push操作将无效。

解决方案是：

1. 从self.navigationController.viewControllers中拿出需要保留的View Controller放到一个数组中

2. 向数组中添加需要push的View Controller

3. 调用[self.navigationController setViewControllers:array animated:YES]

InvestmentViewController *investmentList = [[InvestmentViewController alloc] init];
investmentList.hidesBottomBarWhenPushed = YES;
NSMutableArray *arrView = [NSMutableArray arrayWithArray:self.navigationController.viewControllers];
int index = (int)[arrView indexOfObject:self];
[arrView removeObjectAtIndex:index];
[arrView addObject:investmentList];
[self.navigationController setViewControllers:arrView animated:YES];