获取位置 android Kotlin

问题描述

我最近添加了获取位置功能.当我尝试显示经度和纬度时，它返回零.

I recently added get location function. When I try to show longitude and latitude, it returns zero.

这是我的 LocationListener 类:

This my LocationListener class:

inner class MylocationListener: LocationListener {
    constructor():super(){
        mylocation= Location("me")
        mylocation!!.longitude
        mylocation!!.latitude
    }

    override fun onLocationChanged(location: Location?) {
        mylocation=location
    }

    override fun onStatusChanged(p0: String?, p1: Int, p2: Bundle?) {}

    override fun onProviderEnabled(p0: String?) {}

    override fun onProviderDisabled(p0: String?) {}
}

这是我的 GetUserLocation 函数:

And this my GetUserLocation function:

fun GetUserLocation(){
    var mylocation= MylocationListener()
    var locationManager=getSystemService(Context.LOCATION_SERVICE) as LocationManager
    locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,0,0.1f,mylocation)
}

这是我返回经度和纬度的函数:

And this my function to return my longitude and latitude:

fun getLoction (view: View){
    prgDialog!!.show();

    GetUserLocation()

    button.setTextColor(getResources().getColor(R.color.green));
    textView.text = mylocation!!.latitude.toFloat().toString()
    Toast.makeText(this, mylocation!!.latitude.toFloat().toString(), Toast.LENGTH_LONG).show()
    Toast.makeText(this, mylocation!!.longitude.toFloat().toString(), Toast.LENGTH_LONG).show()

    prgDialog!!.hide()
}

推荐答案

当 GetUserLocation 返回时，locationManager 超出范围并可能被销毁，阻止 onLocationChanged 被调用并提供更新.

When GetUserLocation returns, locationManager goes out of scope and presumably is destroyed, preventing onLocationChanged from being called and providing updates.

此外，您已在 GetUserLocation 内定义了 mylocation，因此它也超出范围并进一步扼杀了任何机会或您获得更新.

Also, you've defined mylocation inside of GetUserLocation so it also goes out of scope and further kills any chance or your getting an update.

您还没有显示外部 mylocation 的声明位置和方式(在 GetUserLocation 之外)，但是无论它如何声明，它都被内部的一个遮蔽了GetUserLocation.所以你得到的不多.

You have not shown where and how the outer mylocation is declared (outside of GetUserLocation), but how ever it is declared, it is being shadowed by the one inside of GetUserLocation. So you aren't getting much.

以下是您可能如何操作的示例.(变量 thetext 在布局 xml 中定义并使用 Kotlin 扩展访问.)

Here is an example of how you might do it. (The variable thetext is defined within the layout xml and accessed with Kotlin extensions.)

// in the android manifest
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
// allow these through Appliation Manager if necessary

// inside a basic activity
private var locationManager : LocationManager? = null

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)
    setSupportActionBar(toolbar)

    // Create persistent LocationManager reference
    locationManager = getSystemService(LOCATION_SERVICE) as LocationManager?

    fab.setOnClickListener { view ->
        try {
            // Request location updates
            locationManager?.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0L, 0f, locationListener)
        } catch(ex: SecurityException) {
            Log.d("myTag", "Security Exception, no location available")
        }
    }
}

//define the listener
private val locationListener: LocationListener = object : LocationListener {
    override fun onLocationChanged(location: Location) {
        thetext.text = ("" + location.longitude + ":" + location.latitude)
    }
    override fun onStatusChanged(provider: String, status: Int, extras: Bundle) {}
    override fun onProviderEnabled(provider: String) {}
    override fun onProviderDisabled(provider: String) {}
}

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