iOS 笔记 （持续更新。。。）

1.设置父视图透明不影响子视图

view.backgroundColor = [[UIColor blackColor] colorWithAlphaComponent:0.5];

2.给文字加下划线并且添加颜色

[string addAttribute:NSForegroundColorAttributeName value:[UIColor lightGrayColor] range:strRange];  //设置颜色

[str addAttribute:NSUnderlineStyleAttributeName value:[NSNumber numberWithInteger:NSUnderlineStyleSingle] range:strRange];//下划线

3./Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport

4.地图上两点之间的距离计算（经纬度）

double R = 6371000;//地球半径

    double LonA = p1.x *M_PI / 180;

    double LonB = p2.x *M_PI / 180;

    double LatA = p1.y *M_PI / 180;

    double LatB = p2.y *M_PI / 180;

    double d = R *acos(cos(LatA) *cos(LatB) * cos(LonA - LonB) +sin(LatA) * sin(LatB));

    d = sqrt(pow(d,2) + pow(p1.z - p2.z,2));