android 在应用中切换语言

场景: 在设置中切换中英文,然后跳转MainActivity....
步骤:

1.在MyApplication 中初始化语言

public class MyApplication extends Application {
private static MyApplication instance;
public static MyApplication getInstance() {
return instance;
}
public static MyApplication getContext() {
return instance;
}
@Override
public void onCreate() {
super.onCreate();
instance = this;
String savedLanguage = LanguageUtil.getSavedLanguage();
if (TextUtils.isEmpty(savedLanguage)) {
LanguageUtil.setLanguage("cn"); // 设置默认语言为 "cn"
} else {
LanguageUtil.setLanguage(savedLanguage);
}
}
}

2.在 MainActivity 中 @Override onNewIntent()这个方法 , 如果不重写,当launch mode 为single task 时不会刷新

@Override
protected void onNewIntent(Intent intent) {
if (intent.getAction() == "language changed") {
finish();
startActivity(new Intent(this, MainActivity.class));
} else {
super.onNewIntent(intent);
}
}

3.设置界面代码和布局文件

public class SettingActivity extends BaseActivity {

RadioGroup rgLanguage;
RadioButton rbCn;
RadioButton rbEn;
private int checkedRadioButtonId;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_setting_language);

rgLanguage = super.$(this, R.id.rgLanguage);
rbCn = super.$(this, R.id.rbCn);
rbEn = super.$(this, R.id.rbEn);

if ("en".equals(LanguageUtil.getSavedLanguage())) {
rbEn.setChecked(true);
} else {
rbCn.setChecked(true);
}
checkedRadioButtonId = rgLanguage.getCheckedRadioButtonId();

super.$(this, R.id.btnConfirm).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (checkedRadioButtonId != rgLanguage.getCheckedRadioButtonId()) {
if (rbCn.isChecked()) {
LanguageUtil.setLanguage("cn");
} else if (rbEn.isChecked()) {
LanguageUtil.setLanguage("en");
}

finish();
Intent intent = new Intent(MyApplication.getContext(), FirstActivity.class);
intent.setAction("language changed");
startActivity(intent);
} else {
finish();
}
}
});
}
}

////////////////////////////////////////////////////////////////////
public class BaseActivity extends Activity {
public <T extends View> T $(Activity activity, int resId) {
return (T) activity.findViewById(resId);
}
}

设置界面 activity_setting_language.xml 布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">

<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:text="@string/switcher"/>

<RadioGroup
android:id="@+id/rgLanguage"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">

<RadioButton
android:id="@+id/rbCn"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="中文"/>

<RadioButton
android:id="@+id/rbEn"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="English"/>
</RadioGroup>

<Button
android:id="@+id/btnConfirm"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@string/confirm"/>

</LinearLayout>

4.LanguageUtil 代码

public class LanguageUtil {

/**
* 设置语言
*
* @param language "cn" = 中文, "en" = 英文
*/
public static void setLanguage(String language) {
Resources resources = MyApplication.getContext().getResources();
Configuration configuration = resources.getConfiguration();
configuration.locale = new Locale(language);
resources.updateConfiguration(configuration, null);

saveLanguage(language);
}

public static void saveLanguage(String language) {
MyApplication.getContext().getSharedPreferences("settings", Context.MODE_PRIVATE)
.edit().putString("language", language).commit();
}

public static String getSavedLanguage() {
return MyApplication.getContext().getSharedPreferences("settings", Context.MODE_PRIVATE)
.getString("language", "");
}
}

5.AndroidManifest.xml 中添加权限,以及MyApplication的注册

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