Implement plugin entirely in Kotlin

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

@@ -39,7 +39,6 @@ import android.support.v7.app.AppCompatActivity
 import android.support.v7.content.res.AppCompatResources
 import android.support.v7.preference.PreferenceDataStore
 import android.support.v7.widget.TooltipCompat
-import android.text.TextUtils
 import android.util.Log
 import android.view.View
 import android.widget.TextView
@@ -355,7 +354,7 @@ class MainActivity : AppCompatActivity(), ShadowsocksConnection.Interface, Drawe
             }
             else -> null
         }
-        if (TextUtils.isEmpty(sharedStr)) return
+        if (sharedStr.isNullOrEmpty()) return
         val profiles = Profile.findAll(sharedStr).toList()
         if (profiles.isEmpty()) {
             Snackbar.make(findViewById(R.id.snackbar), R.string.profile_invalid_input, Snackbar.LENGTH_LONG).show()

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

@@ -143,7 +143,7 @@ class ProfileConfigFragment : PreferenceFragmentCompatDividers(), Toolbar.OnMenu
     override fun onPreferenceChange(preference: Preference?, newValue: Any?): Boolean = try {
         val selected = pluginConfiguration.selected
         pluginConfiguration = PluginConfiguration(pluginConfiguration.pluginsOptions +
-                (pluginConfiguration.selected to PluginOptions(selected, newValue as String?)), selected)
+                (pluginConfiguration.selected to PluginOptions(selected, newValue as? String?)), selected)
         DataStore.plugin = pluginConfiguration.toString()
         DataStore.dirty = true
         true

mobile/src/main/java/com/github/shadowsocks/bg/BaseService.kt

@@ -29,7 +29,6 @@ import android.os.Build
 import android.os.IBinder
 import android.os.RemoteCallbackList
 import android.support.v4.os.UserManagerCompat
-import android.text.TextUtils
 import android.util.Base64
 import android.util.Log
 import android.widget.Toast
@@ -218,7 +217,7 @@ object BaseService {
         fun onBind(intent: Intent): IBinder? = if (intent.action == Action.SERVICE) data.binder else null
 
         fun checkProfile(profile: Profile): Boolean =
-                if (TextUtils.isEmpty(profile.host) || TextUtils.isEmpty(profile.password)) {
+                if (profile.host.isEmpty() || profile.password.isEmpty()) {
                     stopRunner(true, (this as Context).getString(R.string.proxy_empty))
                     false
                 } else true

mobile/src/main/java/com/github/shadowsocks/plugin/PluginConfiguration.kt

@@ -50,7 +50,7 @@ class PluginConfiguration(val pluginsOptions: Map<String, PluginOptions>, val se
     })
 
     fun getOptions(id: String): PluginOptions = if (id.isEmpty()) PluginOptions() else
-        pluginsOptions.get(id) ?: PluginOptions(id, PluginManager.fetchPlugins()[id]?.defaultConfig)
+        pluginsOptions[id] ?: PluginOptions(id, PluginManager.fetchPlugins()[id]?.defaultConfig)
     val selectedOptions: PluginOptions get() = getOptions(selected)
 
     override fun toString(): String {