Android默认设置App内的语言为中文

1.通用的设置App语言的方法(需要注意版本的变化)

 public static Context initAppLanguage(Context context, String language) {

        if (currentLanguageIsSimpleChinese(context)) {
            Log.e("LanguageUtil", "当前是简体中文");
            return context;
        }

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
            //7.0及以上的方法
            Log.e("LanguageUtil", "7.0及以上");
            return createConfiguration(context, language);
        } else {
            Log.e("LanguageUtil", "7.0以下");
            updateConfiguration(context, language);
            return context;
        }
    }

    /**
     * 7.0及以上的修改app语言的方法
     *
     * @param context  context
     * @param language language
     * @return context
     */
    @RequiresApi(api = Build.VERSION_CODES.N)
    private static Context createConfiguration(Context context, String language) {
        Resources resources = context.getResources();
        Locale locale = new Locale(language);
        Configuration configuration = resources.getConfiguration();
        configuration.setLocale(locale);
        LocaleList localeList = new LocaleList(locale);
        LocaleList.setDefault(localeList);
        configuration.setLocales(localeList);
        return context.createConfigurationContext(configuration);
    }

    /**
     * 7.0以下的修改app语言的方法
     *
     * @param context  context
     * @param language language
     */
    @RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN_MR1)
    private static void updateConfiguration(Context context, String language) {
        Resources resources = context.getResources();
        Locale locale = new Locale(language);
        Locale.setDefault(locale);
        Configuration configuration = resources.getConfiguration();
        configuration.setLocale(locale);
        DisplayMetrics displayMetrics = resources.getDisplayMetrics();
        resources.updateConfiguration(configuration, displayMetrics);
    }

    /**
     * 判断当前的语言是否是简体中文
     *
     * @param context context
     * @return boolean
     */
    private static boolean currentLanguageIsSimpleChinese(Context context) {
        String language;
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
            language = context.getResources().getConfiguration().getLocales().get(0).getLanguage();
        } else {
            language = context.getResources().getConfiguration().locale.getLanguage();
        }
        Log.e("LanguageUtil", "language = " + language);
        return TextUtils.equals("zh", language);
    }

2.初始化的位置

• Android7.0及以前版本，Configuration中的语言相当于是App的全局设置。
• Android7.0及以后版本，使用了LocaleList。Configuration中的语言设置可能获取的不同，而是生效于各自的Context。也就是语言需要植入到Context中，每个Context都植入一遍。

7.0及以前的版本，在Application中的初始化(注意在项目清单文件中注册applicaiton)

public class MyApplication extends Application implements Application.ActivityLifecycleCallbacks {

    private boolean isRunInBackground;
    private int appCount;

    @Override
    public void onCreate() {
        super.onCreate();

        registerActivityLifecycleCallbacks(this);

        initLanguage();
    }


    @Override
    public void onActivityCreated(Activity activity, Bundle savedInstanceState) {

    }

    @Override
    public void onActivityStarted(Activity activity) {
        appCount++;
        if (isRunInBackground) {
            Log.e("TAG", "从后台进入前台");
            isRunInBackground = false;
            //防止应用程序切换到后台，然后通过设置设置语言，最后再将应用程序从后台切换回前台的情况
            initLanguage();
        }
    }

    @Override
    public void onActivityResumed(Activity activity) {

    }

    @Override
    public void onActivityPaused(Activity activity) {

    }

    @Override
    public void onActivityStopped(Activity activity) {
        appCount--;
        if (appCount == 0) {
            isRunInBackground = true;
            Log.e("TAG", "进入了后台");
        }
    }

    @Override
    public void onActivitySaveInstanceState(Activity activity, Bundle outState) {

    }

    @Override
    public void onActivityDestroyed(Activity activity) {

    }

    private void initLanguage() {
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.O) {
            //Application这种方式适用于8.0之前(不包括8.0)的版本
            LanguageUtil.initAppLanguage(getApplicationContext(), "zh");
        }
    }

8.0及之后的版本(在基类BaseActivity中重写attachBaseContext(Context newBase)方法)

public class BaseActivity extends AppCompatActivity {

    @Override
    protected void attachBaseContext(Context newBase) {
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.O) {
            super.attachBaseContext(newBase);
        } else {
            //zh：中文
            super.attachBaseContext(LanguageUtil.initAppLanguage(newBase, "zh"));
        }
    }
}

Github地址：https://github.com/lucklyperson/LanguageDemo

如果问题，欢迎指教。