UIlabel多行文字自动换行 （自动折行）

UIView *footerView = [[UIView alloc]initWithFrame:CGRectMake(10, 100, 300, 180)];UILabel *label = [[UILabel alloc]initWithFrame:CGRectMake(10, 100, 300, 150)];label.text = @"Hello world! Hello world!Hello world! Hello world! Hello world! Hello world! Hello world! Hello world!Hello world! Hello world! Hello world! Hello world! Hello world! Helloworld!";//背景颜色为红色label.backgroundColor = [UIColor redColor];//设置字体颜色为白色label.textColor = [UIColor whiteColor];//文字居中显示label.textAlignment = UITextAlignmentCenter;//自动折行设置label.lineBreakMode = UILineBreakModeWordWrap;label.numberOfLines = 0;