iOS 简单提示view

+(void)showMessage:(NSString *)message
{
UIWindow * window = [UIApplication sharedApplication].keyWindow;
UIView *showview = [[UIView alloc]init];
showview.backgroundColor = [UIColor blackColor];
showview.frame = CGRectMake(1, 1, 1, 1);
showview.alpha = 1.0f;
showview.layer.cornerRadius = 5.0f;
showview.layer.masksToBounds = YES;
[window addSubview:showview];

UILabel *label = [[UILabel alloc]init];
CGSize LabelSize = [message sizeWithFont:[UIFont systemFontOfSize:17] constrainedToSize:CGSizeMake(290, 9000)];
label.frame = CGRectMake(10, 5, LabelSize.width, LabelSize.height);
label.text = message;
label.textColor = [UIColor whiteColor];
label.textAlignment = NSTextAlignmentCenter;
label.backgroundColor = [UIColor clearColor];
label.font = [UIFont boldSystemFontOfSize:13];
[showview addSubview:label];
showview.frame = CGRectMake((ScreenWidth - LabelSize.width - 20)/2, 200, LabelSize.width+20, LabelSize.height+10);
[UIView animateWithDuration:2.5 animations:^{
showview.alpha = 0;
} completion:^(BOOL finished) {
[showview removeFromSuperview];
}];
}

#define ScreenWidth [[UIScreen mainScreen] bounds].size.width//获取屏幕宽度