- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    self.mapView = [[MKMapView alloc] initWithFrame:self.view.bounds];
    self.mapView.mapType = MKMapTypeStandard;
    self.mapView.scrollEnabled = YES;
    //  设置地图不可旋转
    self.mapView.rotateEnabled = NO;
    self.mapView.zoomEnabled = YES;
    self.mapView.showsUserLocation = YES;
    
    //  设置地图中心的经纬度
    CLLocationCoordinate2D center = {39.910650,116.47030};
    //  设置地图显示的范围,数值越小细节越清楚
    MKCoordinateSpan span = {0.01,0.01};
    //  二者合一设置显示区域
    MKCoordinateRegion region = {center,span};
    [self.mapView setRegion:region animated:YES];

    [self.view addSubview:self.mapView];
    
    UILongPressGestureRecognizer *longGesture = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPress:)];
    [self.mapView addGestureRecognizer:longGesture];
    
    //  设置代理
    self.mapView.delegate = self;
    
}

- (void)longPress:(UILongPressGestureRecognizer *)longGesture{
    
    //  获取长按点得坐标
    CGPoint postion = [longGesture locationInView:self.mapView];
    //  将长按点坐标转换为经纬度
    CLLocationCoordinate2D coord2D = [self.mapView convertPoint:postion toCoordinateFromView:self.mapView];
    //  创建一个圆形覆盖层对象
    MKCircle *circle = [MKCircle circleWithCenterCoordinate:coord2D radius:100];
    //  将单个的覆盖层加入到指定的层级
    [self.mapView addOverlay:circle level:MKOverlayLevelAboveLabels];
    
}

//  该方法返回的MKOverlayRenderer负责绘制覆盖层控件
- (MKOverlayRenderer *)mapView:(MKMapView *)mapView rendererForOverlay:(id<MKOverlay>)overlay{

    MKCircle *circle = (MKCircle *)overlay;
    // iOS7之后,推荐使用MKXxxRenderer来负责渲染覆盖层控件
    MKCircleRenderer *circleRend = [[MKCircleRenderer alloc] initWithCircle:circle];
    circleRend.alpha = 0.3;
    //  填充颜色
    circleRend.fillColor = [UIColor blueColor];
    //  边框颜色
    circleRend.strokeColor = [UIColor redColor];
    
    return circleRend;
}


/*********iOS7新增的MKTileOverlay覆盖层*******************************************
- (void)longPress:(UILongPressGestureRecognizer *)longGesture{
    
    //  指定本地图片覆盖
    NSURL *url = [[NSBundle mainBundle] URLForResource:@"hmt" withExtension:@"png"];
    MKTileOverlay *tileOverlay = [[MKTileOverlay alloc] initWithURLTemplate:[url description]];
    [self.mapView addOverlay:tileOverlay];
    
}

//  该方法返回的MKOverlayRenderer负责绘制覆盖层控件
- (MKOverlayRenderer *)mapView:(MKMapView *)mapView rendererForOverlay:(id<MKOverlay>)overlay{
    
    MKTileOverlayRenderer *tileRender = [[MKTileOverlayRenderer alloc] initWithOverlay:(MKTileOverlay *)overlay];
    tileRender.alpha = 0.2;
    return circleRend;
}
*/