Android Google Maps按纬度和经度缩放到特定区域 [英] android google maps zoom to a specific area by lat and long

问题描述

我知道如何按级别缩放Google地图 但是我想要在Google地图上显示特定区域

I know how to zoom google maps by level but what I want is to display a specific area on google maps

我的意思是我只想显示纬度= 24.453&周围的区域.长= 35.547&半径= 200公里

I mean I want just to show the area around Lat = 24.453 & Long = 35.547 & Radius = 200km

如何实现?

推荐答案

感谢@Ken和

Thanks to @Ken and How does this Google Maps zoom level calculation work? I got a solution.

private fun getZoomLevel(radius: Double): Float {
    return if (radius > 0) {
        // val scale = radius / 300 // This constant depends on screen size.
        // Calculate scale depending on screen dpi.
        val scale = radius * resources.displayMetrics.densityDpi / 100000
        (16 - Math.log(scale) / Math.log(2.0)).toFloat()
    } else 16f
}

我不知道它如何取决于屏幕尺寸(dpi，宽度，高度)，所以这是另一个变体:

I don't know how it depends on screen size (dpi, width, height), so this is another variant:

private fun getZoomLevel(radius: Double): Float {
    return if (radius > 0) {
        val metrics = resources.displayMetrics
        val size = if (metrics.widthPixels < metrics.heightPixels) metrics.widthPixels
        else metrics.heightPixels
        val scale = radius * size / 300000
        (16 - Math.log(scale) / Math.log(2.0)).toFloat()
    } else 16f
}

用法:

private fun zoomMapToRadius(latitude: Double, longitude: Double, radius: Double) {
    val position = LatLng(latitude, longitude)
    val center = CameraUpdateFactory.newLatLngZoom(position, getZoomLevel(radius))
    googleMap?.animateCamera(center)
}

或

private fun zoomMapToRadius(/*latitude: Double, longitude: Double,*/ radius: Double) {
    //val position = LatLng(latitude, longitude)
    //val center = CameraUpdateFactory.newLatLng(position)
    //googleMap?.moveCamera(center)
    val zoom = CameraUpdateFactory.zoomTo(getZoomLevel(radius))
    googleMap?.animateCamera(zoom)
}

更新

一个更准确的解决方案在这里: https://stackoverflow.com/a/56464293/2914140 .

A more accurate solution is here: https://stackoverflow.com/a/56464293/2914140.

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