kotlin的多语安卓应用程序给出了这样的消息:在onCreate()之前，系统服务不可用于活动

Question

我试图按照本教程在android中制作一个多语言应用程序：https://www.youtube.com/watch?v=ywF-ySiBAsc

我在开发应用程序时使用了kotlin，但我遇到了一些错误，到目前为止我无法处理。

这是app_intro活动：

package com.xr.mapbased
import android.content.Context
import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.support.v7.app.AlertDialog
import android.widget.Button
import android.widget.TextView
import uk.co.chrisjenx.calligraphy.CalligraphyContextWrapper
import uk.co.chrisjenx.calligraphy.CalligraphyConfig
import android.content.DialogInterface
import android.media.VolumeShaper
import com.google.android.gms.stats.WakeLock
import java.util.*
import android.content.res.Configuration
import android.content.res.Resources
import android.preference.PreferenceManager
import android.view.Menu
import android.view.MenuItem
import com.climaxwares.mapbased.helper.LocaleHelper

class app_intro : AppCompatActivity() {
var btnSingIn: Button? = null
var btnRegister:Button? = null
var btnChangeLang:TextView? = null
var LocaleAttach:   LocaleHelper? = null
override fun attachBaseContext(newBase: Context) {
super.attachBaseContext(LocaleAttach?.onAttach(newBase,"en"))
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
CalligraphyConfig.initDefault(CalligraphyConfig.Builder()
.setDefaultFontPath("fonts/Roboto-medium.ttf")
.setFontAttrId(R.attr.fontPath)
.build()
)
val getLang = PreferenceManager.getDefaultSharedPreferences(baseContext)
setContentView(R.layout.activity_app_intro)
btnRegister = findViewById(R.id.RegisterBtn) as Button
btnSingIn = findViewById(R.id.SignInBtn) as Button
btnChangeLang = findViewById(R.id.change_lang) as TextView
val Language: String = getLang.getString("language","ar")
if(Language == null)
getLang.edit().putString("language","en")
updateView("ar")

}
private fun updateView(Language: String) {
val context: Context = LocaleAttach!!.setLocale(this,Language)
val resources: Resources = context.getResources();
btnSingIn!!.text = resources.getString(R.string.sign_in)
}
override fun onCreateOptionsMenu(menu: Menu): Boolean{
menuInflater.inflate(R.menu.lang_menu,menu)
return true
}
override fun onOptionsItemSelected(menuItem: MenuItem?): Boolean {
val getLang = PreferenceManager.getDefaultSharedPreferences(baseContext)
if(menuItem!!.getItemId() == R.id.language_en){
getLang.edit().putString("language","en")
updateView("en")
}

if(menuItem.getItemId() == R.id.language_ar){
getLang.edit().putString("language","ar")
updateView("ar")
}
return true
}
}

我得到了这些错误：

E/AndroidRuntime：致命异常：main流程：com.climaxwares.map-based，PID:10816java.lang.RuntimeException：无法启动活动ComponentInfo｛com.climaxwares.mapbased/com.climaxwares.mapbased.app_intro｝：java.lang.IollegalStateException：在onCreate()之前，系统服务对Activities不可用在android.app.ActivityThread.performLaunchActivity(ActivityThreads.java：2377)在android.app.ActivityThread.handleLaunchActivity(ActivityThreads.java：2429)在android.app.ActivityThread.access上$800(ActivityThreads.java:151)在android.app.ActivityThread$H.handleMessage(ActivityThreads.java:1342)在android.os.Handler.dispatchMessage(Handler.java:110)在android.os.Looper.loop(Looper.java：193)在android.app.ActivityThread.main(ActivityThreads.java:5533)位于java.lang.reflect.Method.invokeNative(Native Method)位于java.lang.reflect.Method.ioke(Method.java:515)网址：com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:829)网址：com.android.internal.os.ZygoteInit.main(ZygoteNit.java:645)在dalvik.system.NativeStart.main(本地方法)由以下原因引起：java.lang.IollegalStateException：onCreate()之前的活动无法使用系统服务在android.app.Activity.getSystemService(Activity.java:4595)在android.view.LayoutInflater.from(LayoutInflater.java:211)网址：com.android.internal.policy.impl.PhoneWindow.(PhoneWindow.java:289)网址：com.android.internal.policy.impl.policy.makeNewWindow(policy.java:61)网址：com.android.internal.policy.PolicyManager.makeNewWindow(PolicyManager.java:57)在android.app.Activity.attach(Activity.java:5253)在android.app.ActivityThread.performLaunchActivity(ActivityThreads.java:2308)在android.app.ActivityThread.handleLaunchActivity(ActivityThreads.java：2429)在android.app.ActivityThread.access上$800(ActivityThreads.java:151)在android.app.ActivityThread$H.handleMessage(ActivityThreads.java:1342)在android.os.Handler.dispatchMessage(Handler.java:110)在android.os.Looper.loop(Looper.java：193)在android.app.ActivityThread.main(ActivityThreads.java:5533)位于java.lang.reflect.Method.invokeNative(Native Method)位于java.lang.reflect.Method.ioke(Method.java:515)网址：com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:829)网址：com.android.internal.os.ZygoteInit.main(ZygoteNit.java:645)在dalvik.system.NativeStart.main(本地方法)

我会在这里回答更多问题，提前感谢：)

Answer 1

我们在Kotlin中没有静态方法？！

这就是问题所在，它在适配器文件本身中，而不是在MainActivity中。

所以当我试图调用这个类时，它给了我上面的错误。我发现这个教程非常有用。

https://android.jlelse.eu/daily-kotlin-static-methods-9330552cde8a

尽管我用Java制作了适配器文件，但它在开发中要直接得多。

这是适配器代码：

package com.xr.mapbased.helper;
import android.annotation.TargetApi;
import android.content.Context;
import android.content.SharedPreferences;
import java.util.*;
import android.content.res.Configuration;
import android.content.res.Resources;
import android.preference.PreferenceManager;
import android.os.Build;
import com.google.android.gms.stats.WakeLock;
import java.util.Locale;

public class LocaleJ {
private static final String SELECTED_LANGUAGE = "Locale.Helper.Selected.Language";
public static Context onAttach(Context context){
String lang = getPersistedData(context, Locale.getDefault().getLanguage());
return setLocale(context,lang);
}
public static Context onAttach(Context context,String defaultLanguage){
String lang = getPersistedData(context,defaultLanguage);
return setLocale(context,lang);
}
private static String getPersistedData(Context context, String lang) {
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);
return preferences.getString(SELECTED_LANGUAGE,lang);
}
private static void persist(Context context, String language) {
SharedPreferences pref = PreferenceManager.getDefaultSharedPreferences(context);
SharedPreferences.Editor editor = pref.edit();
editor.putString(SELECTED_LANGUAGE, language);
editor.apply();
}
public static Context setLocale(Context context, String lang) {
persist(context,lang);
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.N)
return updateResources(context,lang);
return updateResourcesLegacy(context,lang);
}
@TargetApi(Build.VERSION_CODES.N)
private static Context updateResources(Context context, String lang) {
Locale locale = new Locale(lang);
Locale.setDefault(locale);
Configuration config = context.getResources().getConfiguration();
config.setLocale(locale);
config.setLayoutDirection(locale);
return context.createConfigurationContext(config);
}
@SuppressWarnings("deprecation")
private static Context updateResourcesLegacy(Context context, String lang) {
Locale locale = new Locale(lang);
Locale.setDefault(locale);
Resources resources = context.getResources();
Configuration config = resources.getConfiguration();
config.locale = locale;
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1)
config.setLayoutDirection(locale);
resources.updateConfiguration(config,resources.getDisplayMetrics());
return context;
}

}