我的app模块启动了一个位置跟踪器/提示器，作为前台服务运行。我工作得很好，但是Android Studio给了我这个警告:
private lateinit var locationActivity: Activity
=> Do not place Android context classes in static fields; this is a memory leak
模块代码如下:
package com.DevID.AppID
import android.Manifest
import android.app.*
import android.content.BroadcastReceiver
import android.content.Context
import android.content.Intent
import android.content.pm.PackageManager
import android.location.Location
import android.net.Uri
import android.os.Build
import android.os.IBinder
import android.os.Looper
import androidx.core.app.NotificationCompat
import androidx.core.content.ContextCompat
import com.android.volley.Request
import com.android.volley.RequestQueue
import com.android.volley.toolbox.StringRequest
import com.android.volley.toolbox.Volley
import com.google.android.gms.location.*
import java.util.*
import kotlin.concurrent.fixedRateTimer
private var createCount = 0
private var initialized = false
private var LocationServiceRunning = false
private var locationService: LocationService = LocationService()
private lateinit var locationIntent: Intent
private lateinit var locationCallback: LocationCallback
private lateinit var VolleyQueue: RequestQueue
private lateinit var locationActivity: Activity // **WARNING: Do not place Android context classes in static fields; this is a memory leak**
fun startLocationService(activity: Activity, enable: Boolean) {
LocationService.Enabled = enable
locationIntent = Intent(activity, locationService.javaClass)
VolleyQueue = Volley.newRequestQueue(activity)
locationActivity = activity
if (LocationService.Enabled) {
if (!LocationServiceRunning) {
if (ContextCompat.checkSelfPermission(activity, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
reportEvent("NOPERMIS")
val errorNotif = createNotification(
activity,
"Error: location not available",
"Click to open settings and allow location access",
NotificationCompat.PRIORITY_MAX,
Notification.CATEGORY_ERROR,
Intent(android.provider.Settings.ACTION_APPLICATION_DETAILS_SETTINGS, Uri.fromParts("package", activity.packageName, null))
)
(activity.getSystemService(Service.NOTIFICATION_SERVICE) as NotificationManager).notify(99, errorNotif)
} else {
reportEvent("STARTING")
createCount = 0
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) { // Oreo = Android 8.0 = API level 26
activity.startForegroundService(locationIntent)
} else {
activity.startService(locationIntent)
}
}
}
} else {
if (LocationServiceRunning) {
reportEvent("STOPPING")
activity.stopService(locationIntent)
} else {
(activity.getSystemService(Service.NOTIFICATION_SERVICE) as NotificationManager).cancel(99) // Clean up any error notifications
}
}
}
fun reportEvent(event: String) {
VolleyQueue.add(StringRequest(Request.Method.GET, "${LocationService.ReportURL}&report=$event", {}, {}))
}
fun createNotification(activity: Activity, title: String, text: String, priority: Int, category: String?, intent: Intent): Notification {
val channelID = "LOCATION_SERVICE"
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
val channelName = "Location Service"
val chan = NotificationChannel(channelID, channelName, NotificationManager.IMPORTANCE_LOW)
chan.lockscreenVisibility = Notification.VISIBILITY_PUBLIC
val manager = activity.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
manager.createNotificationChannel(chan)
}
return NotificationCompat.Builder(activity, channelID)
.setOngoing(true)
.setSmallIcon(R.drawable.ic_stat_ic_notification)
.setContentTitle(title)
.setContentText(if (text == "") null else text)
.setPriority(priority)
.setCategory(category)
.setContentIntent(
TaskStackBuilder.create(activity)
.addNextIntent(intent)
.getPendingIntent(0, PendingIntent.FLAG_UPDATE_CURRENT)
)
.setShowWhen(true)
.setWhen(System.currentTimeMillis())
.build()
}
class LocationService : Service() {
companion object {
var ReportURL: String = ""
var ReportInterval: Long = 60000 // 60 Seconds
var ReportTitle: String = "App is running"
var ReportText: String = ""
var Enabled: Boolean = false
}
private val startTime = now()
private var locGPS: String = ""
private var locCount = 0
private var locTime = startTime
private lateinit var locationTimer: Timer
private fun now(): Int {
return (System.currentTimeMillis() / 1000).toInt()
}
override fun onCreate() {
super.onCreate()
LocationServiceRunning = true
createCount++
if (Enabled) {
showNotification()
startLocationUpdates()
}
}
private fun showNotification() {
val locNotif = createNotification(
locationActivity,
ReportTitle,
ReportText,
NotificationCompat.PRIORITY_MIN,
Notification.CATEGORY_SERVICE,
Intent(this, MainActivity::class.java)
)
startForeground(99, locNotif)
}
private fun startLocationUpdates() {
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
return
}
locationTimer = fixedRateTimer("timer", false, 5000, ReportInterval * 1000) {
val start = now() - startTime
val last = now() - locTime
VolleyQueue.add(StringRequest( // https://developer.android.com/training/volley/simple
Request.Method.GET,
"${ReportURL}&gps=$locGPS&count=$locCount&start=$start&last=$last&wait=${ReportInterval}&agent=App",
{ response ->
val lines = response.lines()
lines.forEach { line ->
when {
line == "start" -> startLocationService(applicationContext as MainActivity, true)
line == "stop" -> startLocationService(applicationContext as MainActivity, false)
line.startsWith("text:") -> ReportText = line.substring(5)
line.startsWith("title:") -> ReportTitle = line.substring(6)
line == "show" -> showNotification()
else -> Log.w("ø_LocationService", "bad response line: $line")
}
}
},
{
ReportTitle = "Error: connection lost"
ReportText = ""
showNotification()
}
))
}
val request = LocationRequest.create().apply {
interval = ReportInterval
fastestInterval = 20000
priority = LocationRequest.PRIORITY_HIGH_ACCURACY
}
locationCallback = object : LocationCallback() {
override fun onLocationResult(locationResult: LocationResult) {
val location: Location = locationResult.lastLocation
locGPS = location.latitude.toString() + "," + location.longitude.toString()
locCount++
locTime = now()
}
}
LocationServices
.getFusedLocationProviderClient(this)
.requestLocationUpdates(request, locationCallback, Looper.getMainLooper())
initialized = true
}
override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
super.onStartCommand(intent, flags, startId)
return START_STICKY
}
override fun onBind(intent: Intent?): IBinder? {
return null
}
override fun onDestroy() {
super.onDestroy()
LocationServiceRunning = false
if (initialized) {
LocationServices
.getFusedLocationProviderClient(this)
.removeLocationUpdates(locationCallback)
locationTimer.cancel()
}
if (Enabled) {
reportEvent("RESTARTING")
val broadcastIntent = Intent()
broadcastIntent.action = "restartservice"
broadcastIntent.setClass(this, LocationServiceRestarter::class.java)
this.sendBroadcast(broadcastIntent)
}
}
}
class LocationServiceRestarter : BroadcastReceiver() {
override fun onReceive(context: Context?, intent: Intent?) {
Log.i("ø_LocationService", "LocationServiceRestarter triggered")
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
context!!.startForegroundService(Intent(context, LocationService::class.java))
} else {
context!!.startService(Intent(context, LocationService::class.java))
}
}
}
我可以避免内存泄漏而不完全重写我的代码吗?
删除
private lateinit var locationActivity: Activity
你需要的是一个Context，你的LocationService是一个Context。
fun startLocationService(activity: Activity, enable: Boolean) { ... }
fun createNotification(activity: Activity, ...) { ... }
fun startLocationService(context: Context, enable: Boolean) { ... }
fun createNotification(context: Context, ...) { ... }
和调用createNotification传递this作为第一个参数，而不是locationActivity。
你也可以使用applicationContext来代替locationActivity，就像你在调用startLocationService时所做的那样。