aidl实现Android系统语言切换

参考和引用：ytmfdw博文

简要分析

One step：点击系统Settings直接看logcat

I/ActivityManager( 458): Config changes=2004 {1.0 ?mcc?mnc ja_JP ldltr sw800dp w800dp h1207dp 160dpi xlrg port finger -keyb/v/h -nav/h s.9}

I/ContactsProvider( 680): Locale has changed from zh_TW to ja_JP

I/ContactsDatabaseHelper( 680): Switching to locale ja_JP (ICU v51.1.0.1)

I/ContactsDatabaseHelper( 680): Locale change completed in 490ms

I/ContactsDatabaseHelper( 680): Switching to locale ja_JP (ICU v51.1.0.1)

Two_step ：Settings_apk

packages/apps/Settings/com/android/settings/LocalePicker.Java

发现其中onLocaleSelected(final Locale locale)方法，去调用了fromwork层下的

/frameworks/base/core/Java/com/android/internal/app/LocalePicker

下的updateLocale（）方法

public static void updateLocale(Locale locale) {
try {
IActivityManager am = ActivityManagerNative.getDefault();
Configuration config = am.getConfiguration();
config.setLocale(locale);
am.updateConfiguration(config);
BackupManager.dataChanged("com.android.providers.settings");
} catch (RemoteException e) {
}
}

实现步骤

One_step：添加一个公共方法

/frameworks/base/services/java/com/android/server/am/ActivityManagerService.java

public void updateLanguage(Configuration values) {
if (mHeadless)
return;
int changes = 0;
boolean kept = true;
if (values != null) {
Configuration newConfig = new Configuration(mConfiguration);
changes = newConfig.updateFrom(values);
if (changes != 0) {
if (DEBUG_SWITCH || DEBUG_CONFIGURATION) {
Slog.i(TAG, "Updating configuration to: " + values);
}
EventLog.writeEvent(EventLogTags.CONFIGURATION_CHANGED, changes);
if (values.locale != null) {
saveLocaleLocked(values.locale,
!values.locale.equals(mConfiguration.locale),
values.userSetLocale);
Slog.i(TAG, "update language::" + values.toString());
}
}
}
}

Two_step：修改代理

/frameworks/base/core/java/android/app/ActivityManagerNative.java

updateLanguage方法

public void updateLanguage(Configuration values) throws RemoteException
{
Parcel data = Parcel.obtain();
Parcel reply = Parcel.obtain();
data.writeInterfaceToken(IActivityManager.descriptor);
values.writeToParcel(data, 0);
mRemote.transact(UPDATE_LANGUAGE_TRANSACTION, data, reply, 0);
reply.readException();
data.recycle();
reply.recycle();
}

添加调用接口在方法体中，添加一分支：

public boolean onTransact(int code, Parcel data, Parcel reply, int flags)
throws RemoteException {
switch (code) {
…………
}

case UPDATE_LANGUAGE_TRANSACTION: {
data.enforceInterface(IActivityManager.descriptor);
Configuration config = Configuration.CREATOR.createFromParcel(data);
updateLanguage(config);
reply.writeNoException();
return true;
}

Three_step：声明常量

updateLanguage(Configuration values) 方法

/frameworks/base/core/java/android/app/IActivityManager.java

public void updateLanguage(Configuration values) throws RemoteException;
int UPDATE_LANGUAGE_TRANSACTION = IBinder.FIRST_CALL_TRANSACTION+161;
//（161视情况而定，不能重复）

Four_step：service中添加方法

import com.android.internal.app.LocalePicker;
import android.os.RemoteException;
import java.util.Locale;
import android.content.res.Configuration;
import android.app.IActivityManager;
import android.app.backup.BackupManager;
import android.app.ActivityManagerNative;
......
Locale locale;
public void updateLanguage(String arg,String arg1) {
// switch(arg)
// { case 1:
// locale = new Locale("zh","CN");
// break;
// default:
// break;
// }
locale = new Locale(arg,arg1);
Slog.e(TAG,"ldd_locale locale:"+locale);
String language = locale.getDisplayName();
Slog.e(TAG,"ldd_locale language:"+language);
try {
IActivityManager am = ActivityManagerNative.getDefault();
Configuration config = am.getConfiguration();
Slog.e(TAG,"ldd_locale old_language:"+config);
config.setLocale(locale);
Slog.e(TAG,"ldd_locale new_language:"+config);
am.updateLanguage(config);
Slog.e(TAG,"ldd_locale updateLanguage success");
BackupManager.dataChanged("com.android.providers.settings");
} catch (RemoteException e) {
}
}

Five_step：aidl接口

aidl接口

void updateLanguage(String arg,String arg1);

将3个文件push 到 /system/framework/ 后重启

应用层调用例：

中文简体 reemanService.updateLanguage(zh,CN);

中文香港 reemanService.updateLanguage(zh,HK);

中文繁体（台湾）zh_TW

英文（英国）en_GB

英文（美国）en_US

日文 ja_JP

韩文 ko_KR

调用接口需要系统重启，系统才会更新语言

Six_step：直接调用系统updateLocale方法

直接调用updateLocale()方法来传递参数locale来实现语言切换，而不需要系统重启

service中添加方法

public  void wakeLocale(String arg,String arg1){
Locale wake = new Locale(arg,arg1);
LocalePicker.updateLocale(wake);
Slog.e(TAG,"ldd_locale success");
}

系统签名&添加权限

在AndroidManifest.xml 中添加

android:sharedUserId="android.uid.system"

<uses-permission android:name="android.permission.CHANGE_CONFIGURATION" />

在Android.mk中添加

LOCAL_CERTIFICATE:=platform

在实际项目开发过程中，可能你需要用到第一种方法，后者的方法的应用程序需要内嵌入系统中来编译下执行？系统签名？……