ios 设置 MKMapView 的缩放级别

Setting the zoom level for a MKMapView

提问by system

I have a map which shows correctly, the only thing I want to do now is set the zoom level when it loads. Is there a way to do this?

我有一张显示正确的地图，我现在唯一想做的就是在加载时设置缩放级别。有没有办法做到这一点？

Thanks

谢谢

回答by Carnal

I found myself a solution, which is very simple and does the trick. Use MKCoordinateRegionMakeWithDistancein order to set the distance in meters vertically and horizontally to get the desired zoom. And then of course when you update your location you'll get the right coordinates, or you can specify it directly in the CLLocationCoordinate2Dat startup, if that's what you need to do:

我为自己找到了一个解决方案，它非常简单并且可以解决问题。用于MKCoordinateRegionMakeWithDistance在垂直和水平方向以米为单位设置距离以获得所需的缩放。当然，当您更新您的位置时，您将获得正确的坐标，或者您可以直接在CLLocationCoordinate2D启动时指定它，如果您需要这样做：

CLLocationCoordinate2D noLocation;
MKCoordinateRegion viewRegion = MKCoordinateRegionMakeWithDistance(noLocation, 500, 500);
MKCoordinateRegion adjustedRegion = [self.mapView regionThatFits:viewRegion];          
[self.mapView setRegion:adjustedRegion animated:YES];
self.mapView.showsUserLocation = YES;

Swift:

迅速：

let location = ...
let region = MKCoordinateRegion( center: location.coordinate, latitudinalMeters: CLLocationDistance(exactly: 5000)!, longitudinalMeters: CLLocationDistance(exactly: 5000)!)
mapView.setRegion(mapView.regionThatFits(region), animated: true)

回答by quentinadam

Based on the fact that longitude lines are spaced apart equally at any point of the map, there is a very simple implementation to set the centerCoordinate and zoomLevel:

基于经度线在地图的任何点均等距的事实，有一个非常简单的实现来设置 centerCoordinate 和 zoomLevel：

@interface MKMapView (ZoomLevel)

@property (assign, nonatomic) NSUInteger zoomLevel;

- (void)setCenterCoordinate:(CLLocationCoordinate2D)centerCoordinate
                  zoomLevel:(NSUInteger)zoomLevel
                   animated:(BOOL)animated;

@end


@implementation MKMapView (ZoomLevel)

- (void)setZoomLevel:(NSUInteger)zoomLevel {
    [self setCenterCoordinate:self.centerCoordinate zoomLevel:zoomLevel animated:NO];
}

- (NSUInteger)zoomLevel {
    return log2(360 * ((self.frame.size.width/256) / self.region.span.longitudeDelta)) + 1;
}

- (void)setCenterCoordinate:(CLLocationCoordinate2D)centerCoordinate
zoomLevel:(NSUInteger)zoomLevel animated:(BOOL)animated {
    MKCoordinateSpan span = MKCoordinateSpanMake(0, 360/pow(2, zoomLevel)*self.frame.size.width/256);
    [self setRegion:MKCoordinateRegionMake(centerCoordinate, span) animated:animated];
}

@end

回答by PostMan

It's not built in, but I've seen / used thiscode. This allows you to use this:

它不是内置的，但我见过/使用过这段代码。这允许您使用它：

[mapView setCenterCoordinate:myCoord zoomLevel:13 animated:YES];

Note: This is not my code, I did not write it, so therefore can't take credit for it

注意：这不是我的代码，不是我写的，所以不能相信它

回答by DerekH

You can also zoom by using MKCoordinateRegion and setting its span latitude & longitude delta. Below is a quick reference and hereis the iOS reference. It won't do anything fancy but should allow you to set zoom when it draws the map.

您还可以使用 MKCoordinateRegion 并设置其跨度纬度和经度增量进行缩放。下面是一个快速参考，这里是 iOS 参考。它不会做任何花哨的事情，但应该允许您在绘制地图时设置缩放。

---

---

MKCoordinateRegion region;
region.center.latitude = {desired lat};
region.center.longitude = {desired lng};
region.span.latitudeDelta = 1;
region.span.longitudeDelta = 1;
mapView.region = region;

---

---

Edit 1:

编辑1：

MKCoordinateRegion region;
region.center.latitude = {desired lat};
region.center.longitude = {desired lng};
region.span.latitudeDelta = 1;
region.span.longitudeDelta = 1;
region = [mapView regionThatFits:region];
[mapView setRegion:region animated:TRUE];

回答by Vlad Spreys

Swift implementation

Swift 实现

import Foundation
import MapKit

class MapViewWithZoom: MKMapView {

    var zoomLevel: Int {
        get {
            return Int(log2(360 * (Double(self.frame.size.width/256) / self.region.span.longitudeDelta)) + 1);
        }

        set (newZoomLevel){
            setCenterCoordinate(coordinate:self.centerCoordinate, zoomLevel: newZoomLevel, animated: false)
        }
    }

    private func setCenterCoordinate(coordinate: CLLocationCoordinate2D, zoomLevel: Int, animated: Bool) {
        let span = MKCoordinateSpan(latitudeDelta: 0, longitudeDelta: 360 / pow(2, Double(zoomLevel)) * Double(self.frame.size.width) / 256)
        setRegion(MKCoordinateRegion(center: coordinate, span: span), animated: animated)
    }
}

回答by swennemen

A simple Swift implementation, if you use outlets.

一个简单的 Swift 实现，如果你使用 outlet。

@IBOutlet weak var mapView: MKMapView! {
    didSet {
        let noLocation = CLLocationCoordinate2D()
        let viewRegion = MKCoordinateRegionMakeWithDistance(noLocation, 500, 500)
        self.mapView.setRegion(viewRegion, animated: false)
    }
}

Based on @Carnal's answer.

基于@Carnal 的回答。

回答by zero3nna

For Swift 3it's pretty fast forward:

对于Swift 3，它的速度非常快：

private func setMapRegion(for location: CLLocationCoordinate2D, animated: Bool)
{
    let viewRegion = MKCoordinateRegionMakeWithDistance(location, <#T##latitudinalMeters: CLLocationDistance##CLLocationDistance#>, <#T##longitudinalMeters: CLLocationDistance##CLLocationDistance#>)
    MapView.setRegion(viewRegion, animated: animated)
}

Just define the lat-, long-Meters <CLLocationDistance>and the mapView will fit the zoom level to your values.

只需定义经纬度，<CLLocationDistance>mapView 就会根据您的值调整缩放级别。

回答by Nick

Based on @AdilSoomro's great answer. I have come up with this:

基于@AdilSoomro 的精彩回答。我想出了这个：

@interface MKMapView (ZoomLevel)
- (void)setCenterCoordinate:(CLLocationCoordinate2D)centerCoordinate
                  zoomLevel:(NSUInteger)zoomLevel
                   animated:(BOOL)animated;

-(double) getZoomLevel;
@end



@implementation MKMapView (ZoomLevel)

- (void)setCenterCoordinate:(CLLocationCoordinate2D)centerCoordinate
                  zoomLevel:(NSUInteger)zoomLevel animated:(BOOL)animated {
    MKCoordinateSpan span = MKCoordinateSpanMake(0, 360/pow(2, zoomLevel)*self.frame.size.width/256);
    [self setRegion:MKCoordinateRegionMake(centerCoordinate, span) animated:animated];
}


-(double) getZoomLevel {
    return log2(360 * ((self.frame.size.width/256) / self.region.span.longitudeDelta));
}

@end

回答by dispatchMain

I hope following code fragment would help you.

我希望以下代码片段对您有所帮助。

- (void)handleZoomOutAction:(id)sender {
    MKCoordinateRegion newRegion=MKCoordinateRegionMake(mapView.region.center,MKCoordinateSpanMake(mapView.region.s       pan.latitudeDelta/0.5, mapView.region.span.longitudeDelta/0.5));
    [mapView setRegion:newRegion];
}


- (void)handleZoomInAction:(id)sender {
    MKCoordinateRegion newRegion=MKCoordinateRegionMake(mapView.region.center,MKCoordinateSpanMake(mapView.region.span.latitudeDelta*0.5, mapView.region.span.longitudeDelta*0.5));
    [mapView setRegion:newRegion];
}

You can choose any value in stead of 0.5 to reduce or increase zoom level. I have used these methods on click of two buttons.

您可以选择任何值而不是 0.5 来减少或增加缩放级别。我在点击两个按钮时使用了这些方法。

回答by David T

A Swift 2.0 answer utilising NSUserDefaults to save and restore the map's zoom and position.

使用 NSUserDefaults 保存和恢复地图缩放和位置的 Swift 2.0 答案。

Function to save the map position and zoom:

保存地图位置和缩放的函数：

func saveMapRegion() {
    let mapRegion = [
        "latitude" : mapView.region.center.latitude,
        "longitude" : mapView.region.center.longitude,
        "latitudeDelta" : mapView.region.span.latitudeDelta,
        "longitudeDelta" : mapView.region.span.longitudeDelta
    ]
    NSUserDefaults.standardUserDefaults().setObject(mapRegion, forKey: "mapRegion")
}

Run the function each time the map is moved:

每次移动地图时运行该函数：

func mapView(mapView: MKMapView, regionDidChangeAnimated animated: Bool) 
{
        saveMapRegion();
}

Function to save the map zoom and position:

保存地图缩放和位置的函数：

func restoreMapRegion() 
{
    if let mapRegion = NSUserDefaults.standardUserDefaults().objectForKey("mapRegion") 
    {

        let longitude = mapRegion["longitude"] as! CLLocationDegrees
        let latitude = mapRegion["latitude"] as! CLLocationDegrees
        let center = CLLocationCoordinate2D(latitude: latitude, longitude: longitude)

        let longitudeDelta = mapRegion["latitudeDelta"] as! CLLocationDegrees
        let latitudeDelta = mapRegion["longitudeDelta"] as! CLLocationDegrees
        let span = MKCoordinateSpan(latitudeDelta: latitudeDelta, longitudeDelta: longitudeDelta)

        let savedRegion = MKCoordinateRegion(center: center, span: span)

        self.mapView.setRegion(savedRegion, animated: false)
    }
}

Add this to viewDidLoad:

将此添加到 viewDidLoad：

restoreMapRegion()