iOS常用小知识纪录

空位补0:   [NSString stringWithFormat:@"%ld:%02ld",(long)self.hour,(long)self.minute];

给view设置圆角:  bgView.layer.cornerRadius = 8.;

圆形的Button : startBtn.layer.cornerRadius = 39.;//（大约这个值，就为圆形了。）

 startBtn.layer.borderWidth = 1.0;

 startBtn.layer.borderColor =[UIColor blueColor].CGColor;

 startBtn.clipsToBounds = YES;//去除边界

给UIView设置图片

 UIImage *image = [UIImage imageNamed:@"xxxxx"];

 UIView *myView = [[UIView alloc] init];

 myView.backgroundColor = [UIColor colorWithPatternImage:image];

// 设置左上右上角为圆角   

UIView *alertTimerView = [[UIView alloc] init];

alertTimerView.center = CGPointMake(MainScreenWidth * 0.5, MainScreenHeight * 0.5);

alertTimerView.bounds = CGRectMake(0, 0, alertTimerViewW, alertTimerViewH);

alertTimerView.backgroundColor = [UIColor colorWithPatternImage:image];

alertTimerView.layer.cornerRadius = alertTimerViewCornerRadius;

UIBezierPath *topBezierPath = [UIBezierPath bezierPathWithRoundedRect:alertTimerView.bounds byRoundingCorners:UIRectCornerTopLeft |UIRectCornerTopRight cornerRadii:CGSizeMake(alertTimerViewCornerRadius , alertTimerViewCornerRadius)];

CAShapeLayer *topMaskLayer = [CAShapeLayer layer];

topMaskLayer.frame = alertTimerView.bounds;
topMaskLayer.path = topBezierPath.CGPath;
alertTimerView.layer.mask = topMaskLayer;

[self.view addSubview:alertTimerView];

// 刷新指定行

　　NSIndexPath *path = [NSIndexPath indexPathForRow:alertView.tag inSection:0];

     [self.tableview reloadRowsAtIndexPaths:@[path] withRowAnimation:UITableViewRowAnimationRight];

// 刷新指定collectionView

　　NSIndexPath *path = [NSIndexPath indexPathForRow:indexPath.row inSection:0];

     [self.collectionView reloadItemsAtIndexPaths:@[path]];

 //  遍历打印数组

 　NSEnumerator *enu = [_selectTreats objectEnumerator];

    id obj;

    while (obj = enu.nextObject) {

        NSLog(@"obj===%@==",obj);

    }    

    [_selectTreats enumerateObjectsWithOptions:NSEnumerationReverse usingBlock:^(id str,NSUInteger index, BOOL* te){

        NSLog(@"%@,%d",str,index);

    }];