去除nsstring中的空格
NSCharacterSet *whitespace = [NSCharacterSet whitespaceAndNewlineCharacterSet];
NSString *username = [mUsernameField stringValue];
username = [username stringByTrimmingCharactersInSet:whitespace];
让覆盖在下面层的视图接受触摸事件
searchImage.exclusiveTouch = YES;//第一层
searchImage.userInteractionEnabled = NO;
myMapView.exclusiveTouch = NO;//第二层
myMapView.userInteractionEnabled = YES;
防止屏幕暗掉锁屏
[[UIApplication sharedApplication] setIdleTimerDisabled:YES];
状态栏的网络活动风火轮是否旋转
[UIApplication sharedApplication].networkActivityIndicatorVisible，默认值是NO。
键盘透明
textField.keyboardAppearance = UIKeyboardAppearanceAlert;
截取屏幕图片
//创建一个基于位图的图形上下文并指定大小为CGSizeMake(200,400)
UIGraphicsBeginImageContext(CGSizeMake(200,400));
//renderInContext 呈现接受者及其子范围到指定的上下文
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
//返回一个基于当前图形上下文的图片
UIImage *aImage = UIGraphicsGetImageFromCurrentImageContext();
//移除栈顶的基于当前位图的图形上下文
UIGraphicsEndImageContext();
//以png格式返回指定图片的数据
imageData = UIImagePNGRepresentation(aImage);
更改cell选中的背景
UIView *myview = [[UIView alloc] init];
myview.frame = CGRectMake(0, 0, 320, 47);
myview.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"0006.png"]];
cell.selectedBackgroundView = myview;
从本地加载图片
NSString *boundle = [[NSBundle mainBundle] resourcePath];
[web1
loadHTMLString:[NSString stringWithFormat:@"<img
src='http://fei263.blog.163.com/blog/0001.png'/>"] baseURL:[NSURL
fileURLWithPath:boundle]];
View自己调用自己的方法:
[self performSelector:@selector(loginToNext) withObject:nil afterDelay:2];//黄色段为方法名,和延迟几秒执行.
动画:一个接一个地显示一系列的图象
NSArray
*myImages = [NSArray arrayWithObjects: [UIImage
imageNamed:@"myImage1.png"], [UIImage imageNamed:@"myImage2.png"],
[UIImage imageNamed:@"myImage3.png"], [UIImage
imageNamed:@"myImage4.gif"], nil];
UIImageView *myAnimatedView = [UIImageView alloc];
[myAnimatedView initWithFrame:[self bounds]];
myAnimatedView.animationImages = myImages; //animationImages属性返回一个存放动画图片的数组
myAnimatedView.animationDuration = 0.25; //浏览整个图片一次所用的时间
myAnimatedView.animationRepeatCount = 0; // 0 = loops forever 动画重复次数
[myAnimatedView startAnimating];
[self addSubview:myAnimatedView];
[myAnimatedView release];