ios开发小技巧

1.设置UILable  的行间距  和 计算带行间距的高度

/*

UILabel* 展示的控件

(NSString*)str  内容

withFont:(float)font 字体大小

WithSpace:(float)space 行间距

*/

//给UILabel设置行间距和字间距

-(void)setLabelSpace:(UILabel*)label withValue:(NSString*)str withFont:(float)font WithSpace:(float)space{

NSMutableParagraphStyle *paraStyle = [[NSMutableParagraphStyle alloc] init];

paraStyle.lineBreakMode = NSLineBreakByCharWrapping;

paraStyle.alignment = NSTextAlignmentLeft;

paraStyle.lineSpacing = space;//设置行间距

paraStyle.hyphenationFactor = 1.0;

paraStyle.firstLineHeadIndent = 0.0;

paraStyle.paragraphSpacingBefore = 0.0;

paraStyle.headIndent = 0;

paraStyle.tailIndent = 0;

//设置字间距 NSKernAttributeName:@1.5f

UIFont *tfont = [UIFont systemFontOfSize:font];

NSDictionary *dic = @{NSFontAttributeName:tfont, NSParagraphStyleAttributeName:paraStyle, NSKernAttributeName:@1.5f

};

NSAttributedString *attributeStr = [[NSAttributedString alloc] initWithString:str attributes:dic];

label.attributedText = attributeStr;

}

/*

计算UILabel的高度(带有行间距的情况)

(NSString*)str  内容

withFont:(float)font 字体大小

WithSpace:(float)space 行间距

(CGFloat)width  UILable的宽度

*/

//计算UILabel的高度(带有行间距的情况)

-(CGFloat)getSpaceLabelHeight:(NSString*)str withFont:(float)font withWidth:(CGFloat)width WithSpace:(float)space{

NSMutableParagraphStyle *paraStyle = [[NSMutableParagraphStyle alloc] init];

paraStyle.lineBreakMode = NSLineBreakByCharWrapping;

paraStyle.alignment = NSTextAlignmentLeft;

paraStyle.lineSpacing = space;

paraStyle.hyphenationFactor = 1.0;

paraStyle.firstLineHeadIndent = 0.0;

paraStyle.paragraphSpacingBefore = 0.0;

paraStyle.headIndent = 0;

paraStyle.tailIndent = 0;

UIFont *tfont = [UIFont systemFontOfSize:font];

NSDictionary *dic = @{NSFontAttributeName:tfont, NSParagraphStyleAttributeName:paraStyle, NSKernAttributeName:@1.5f

};

CGSize size = [str boundingRectWithSize:CGSizeMake(width, CGFLOAT_MAX) options:NSStringDrawingUsesLineFragmentOrigin attributes:dic context:nil].size;

returnsize.height;

}

2.禁止程序运行时自动锁屏

[[UIApplication sharedApplication] setIdleTimerDisabled:YES];

3.取消系统的返回手势

self.navigationController.interactivePopGestureRecognizer.enabled = NO;

4.百度坐标跟火星坐标相互转换

//百度转火星坐标

+ (CLLocationCoordinate2D )bdToGGEncrypt:(CLLocationCoordinate2D)coord

{

double x = coord.longitude - 0.0065, y = coord.latitude - 0.006;

double z = sqrt(x * x + y * y) - 0.00002 * sin(y * M_PI);

double theta = atan2(y, x) - 0.000003 * cos(x * M_PI);

CLLocationCoordinate2D transformLocation ;

transformLocation.longitude = z * cos(theta);

transformLocation.latitude = z * sin(theta);

returntransformLocation;

}

//火星坐标转百度坐标

+ (CLLocationCoordinate2D )ggToBDEncrypt:(CLLocationCoordinate2D)coord

{

double x = coord.longitude, y = coord.latitude;

double z = sqrt(x * x + y * y) + 0.00002 * sin(y * M_PI);

double theta = atan2(y, x) + 0.000003 * cos(x * M_PI);

CLLocationCoordinate2D transformLocation ;

transformLocation.longitude = z * cos(theta) + 0.0065;

transformLocation.latitude = z * sin(theta) + 0.006;

returntransformLocation;

}

6.简单写出增、删、改、查的SQL语句

增:   insert into tb_blogs(name, url) values('aaa','http://www.baidu.com');

删：deletefrom tb_blogs where blogid = 1;

改：update tb_blogs set url ='www.baidu.com'where blogid = 1;

查:   select name, url from tb_blogs where blogid = 1;