Fix incorrect back button color

mobile/src/main/java/com/github/shadowsocks/AppManager.kt

@@ -38,6 +38,7 @@ import android.support.v7.widget.DefaultItemAnimator
 import android.support.v7.widget.LinearLayoutManager
 import android.support.v7.widget.RecyclerView
 import android.support.v7.widget.Toolbar
+import android.util.TypedValue
 import android.view.*
 import android.widget.ImageView
 import android.widget.Switch
@@ -49,6 +50,7 @@ import com.github.shadowsocks.database.ProfileManager
 import com.github.shadowsocks.preference.DataStore
 import com.github.shadowsocks.utils.DirectBoot
 import com.github.shadowsocks.utils.Key
+import com.github.shadowsocks.utils.resolveResourceId
 import com.github.shadowsocks.utils.thread
 import java.util.concurrent.atomic.AtomicBoolean
 
@@ -181,9 +183,7 @@ class AppManager : AppCompatActivity(), Toolbar.OnMenuItemClickListener {
         setContentView(R.layout.layout_apps)
         toolbar = findViewById(R.id.toolbar)
         toolbar.setTitle(R.string.proxied_apps)
-        val arr = obtainStyledAttributes(intArrayOf(R.attr.homeAsUpIndicator))
-        toolbar.navigationIcon = arr.getDrawable(0)
-        arr.recycle()
+        toolbar.setNavigationIcon(theme.resolveResourceId(R.attr.homeAsUpIndicator))
         toolbar.setNavigationOnClickListener {
             val intent = parentActivityIntent
             if (shouldUpRecreateTask(intent) || isTaskRoot)

mobile/src/main/java/com/github/shadowsocks/ScannerActivity.kt

@@ -32,6 +32,7 @@ import android.support.v7.widget.Toolbar
 import android.widget.Toast
 import com.github.shadowsocks.database.Profile
 import com.github.shadowsocks.database.ProfileManager
+import com.github.shadowsocks.utils.resolveResourceId
 import com.google.zxing.Result
 import me.dm7.barcodescanner.zxing.ZXingScannerView
 
@@ -54,9 +55,7 @@ class ScannerActivity : AppCompatActivity(), ZXingScannerView.ResultHandler {
         setContentView(R.layout.layout_scanner)
         val toolbar = findViewById<Toolbar>(R.id.toolbar)
         toolbar.title = title
-        val arr = obtainStyledAttributes(intArrayOf(R.attr.homeAsUpIndicator))
-        toolbar.navigationIcon = arr.getDrawable(0)
-        arr.recycle()
+        toolbar.setNavigationIcon(theme.resolveResourceId(R.attr.homeAsUpIndicator))
         toolbar.setNavigationOnClickListener { navigateUp() }
         scannerView = findViewById(R.id.scanner)
         if (Build.VERSION.SDK_INT >= 25) getSystemService(ShortcutManager::class.java).reportShortcutUsed("scan")

mobile/src/main/java/com/github/shadowsocks/tasker/ConfigActivity.kt

@@ -37,6 +37,7 @@ import android.widget.Switch
 import com.github.shadowsocks.R
 import com.github.shadowsocks.database.Profile
 import com.github.shadowsocks.database.ProfileManager
+import com.github.shadowsocks.utils.resolveResourceId
 
 class ConfigActivity : AppCompatActivity() {
     inner class ProfileViewHolder(view: View) : RecyclerView.ViewHolder(view), View.OnClickListener {
@@ -44,9 +45,7 @@ class ConfigActivity : AppCompatActivity() {
         private val text = itemView.findViewById<CheckedTextView>(android.R.id.text1)
 
         init {
-            val typedArray = obtainStyledAttributes(intArrayOf(android.R.attr.selectableItemBackground))
-            view.setBackgroundResource(typedArray.getResourceId(0, 0))
-            typedArray.recycle()
+            view.setBackgroundResource(theme.resolveResourceId(android.R.attr.selectableItemBackground))
             itemView.setOnClickListener(this)
         }
 

mobile/src/main/java/com/github/shadowsocks/utils/Utils.kt

@@ -3,10 +3,13 @@ package com.github.shadowsocks.utils
 import android.content.BroadcastReceiver
 import android.content.Context
 import android.content.Intent
+import android.content.res.Resources
 import android.os.Build
+import android.support.annotation.AttrRes
 import android.support.v4.app.Fragment
 import android.support.v4.app.FragmentManager
 import android.support.v7.util.SortedList
+import android.util.TypedValue
 import com.github.shadowsocks.App.Companion.app
 import java.lang.reflect.InvocationTargetException
 import java.net.InetAddress
@@ -64,6 +67,15 @@ var Fragment.childFragManager: FragmentManager?
     get() = childFragmentManager
     set(value) = fieldChildFragmentManager.set(this, value)
 
+/**
+ * Based on: https://stackoverflow.com/a/26348729/2245107
+ */
+fun Resources.Theme.resolveResourceId(@AttrRes resId: Int): Int {
+    val typedValue = TypedValue()
+    if (!resolveAttribute(resId, typedValue, true)) throw Resources.NotFoundException()
+    return typedValue.resourceId
+}
+
 private class SortedListIterable<out T>(private val list: SortedList<T>) : Iterable<T> {
     override fun iterator(): Iterator<T> = SortedListIterator(list)
 }