MkMapView取消加载谷歌瓷砖 [英] MkMapView cancel loading google tiles

问题描述

我有一个需要在MkMapView顶部导入叠加贴图的情况。
叠加层完全覆盖下面的谷歌图块，因此不需要加载，加上它增加了应用程序的开销。

I have a case where I need to import an overlay map in top of MkMapView. The overlay totally covers the google tiles below so there is no need loading, plus it adds overhead to the app.

有没有办法告诉mkMapView停止加载磁贴？

Is there a way to tell mkMapView to stop loading tiles?

推荐答案

实际上有两种方法可以实现真正的隐藏Google磁贴方法（johndope解决方案只放一个覆盖在它上面，但不会阻止瓷砖加载。）

Actually there are 2 ways to implement the real "Hide Google tiles" method (johndope solution only puts an overlay on top of it but doesn't prevent the tiles from loading).

请注意，下面描述的选项可能会使您的申请被拒绝，而选项2则不会，但是更复杂。

Beware that option one described below might get your application rejected while option 2 will not but is a bit more complex.

公共部分：检索 MKMapTileView 对象

Common Part: Retrieve the MKMapTileView object

每个 MKMapView 里面都有一个未记录的类： MKMapTileView 。检索它不是拒绝的理由。在此代码中， MKMapView 实例将被称为 mapView

Inside each MKMapView lies an undocumented class of type: MKMapTileView. Retrieving it is NOT a reason for rejection. In this code the MKMapView instance will be called mapView

UIView* scrollview = [[[[mapView subviews] objectAtIndex:0] subviews] objectAtIndex:0];
UIView* mkTiles = [[scrollview subviews] objectAtIndex:0]; // <- MKMapTileView instance

选项1：未记录的方法（!!可以是拒绝理由!!）

if ( [mkTiles respondsToSelector:@selector(setDrawingEnabled:)])
    [mkTiles performSelector:@selector(setDrawingEnabled:) withObject:(id)NO];

这将阻止未记录的方法 setDrawingEnabled to在 MKMapTileView 实例上调用。

This will prevent the undocumented method setDrawingEnabled to be called on the MKMapTileView instance.

选项2：方法调整

在你的控制器实现之外，你会写一些像：

Outside of your controller implementation you will write someting like:

// Import runtime.h to unleash the power of objective C 
#import <objc/runtime.h>

// this will hold the old drawLayer:inContext: implementation
static void (*_origDrawLayerInContext)(id, SEL, CALayer*, CGContextRef);

// this will override the drawLayer:inContext: method
static void OverrideDrawLayerInContext(UIView *self, SEL _cmd, CALayer *layer, CGContextRef context)
{
    // uncommenting this next line will still perform the old behavior
    //_origDrawLayerInContext(self, _cmd, layer, context);

    // change colors if needed so that you don't have a black background
    layer.backgroundColor = RGB(35, 160, 211).CGColor;

    CGContextSetRGBFillColor(context, 35/255.0f, 160/255.0f, 211/255.0f, 1.0f);
    CGContextFillRect(context, layer.bounds);
}

代码中的某处（加载地图视图后！）：

And somewhere in your code (once your map view is loaded!) :

// Retrieve original method object
Method  origMethod = class_getInstanceMethod([mkTiles class], 
                                             @selector(drawLayer:inContext:));

// from this method, retrieve its implementation (actual work done)
_origDrawLayerInContext = (void *)method_getImplementation(origMethod);

// override this method with the one you created    
if(!class_addMethod([mkTiles class],
                    @selector(drawLayer:inContext:), 
                    (IMP)OverrideDrawLayerInContext,
                    method_getTypeEncoding(origMethod)))
{
    method_setImplementation(origMethod, (IMP)OverrideDrawLayerInContext);
}

希望这有助于任何人，此代码最初在此博文。

Hope this helps anyone, this code was originally described in this blog post.

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