Copy this link when reproducing:
http://www.casperlee.com/en/y/blog/198
I believe that supporting for multiple languages is a necessary function of any Android application, so I'm gonna do this in my application now. Just like before, let's take it easy and enjoy a few beautiful photos first. The artist in the following photos is still Angel Wong.
To support for multiple languages in Android application, it involves the following steps:
- Add resource files for each specified language
- Add modules which allow user to change the current language of the application
- Change the language when user starts the application
Add resource files for each specified language
1. Right click on the item "app -> res" in the Project view, a menu will be popped up:
2. Select "New -> Android resource file" from the menu, another dialog will be popped up:
3. Type in "string.xml" as the file name, select "Locale" in the left box, and click on ">>" to move it to the right box, the dialog will change:
4. select "zh: Chinese" in the "Language" box, select "Any Region" from the "Specific Region Only" box, and click "OK" to continue. A new file "string.xml (zh)" will be created and shown under the item "values" in Android Studio:
5. Its actual structure on the disk is shown as below:
6. Open the default file "strings.xml", we can see that there is an item named "app_name". Change its value to:
<string name="app_name">Personal Expense Book</string>7. Open the file "string.xml (zh)" which was created, put the following text in:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="app_name">个人消费记录本</string>
</resources>8. Done.
Add modules which allow user to change the current language of the application
1. Add a main menu to the application.
I. Right click on the item "app -> res" in the Project view, select "New -> Directory" from the popped menu, a dialog will be popped up:
II. Type in "menu", and click "OK" to continue, Android Studio will create a folder named "menu" in the "res" folder.
III. Right click on the item "app -> res -> menu" in the Project view, select "New -> Menu resource file" from the popped menu, a dialog will be popped up:
IV. Type in "main.xml" as the file name, and click "OK" to continue, Android Studio will create the file.
V. Open the file, and put the following text in to define 2 menu items:
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
<item android:id="@+id/miSettings" android:title="@string/mi_settings_title"/>
<item android:id="@+id/miAbout" android:title="@string/mi_about_title"/>
</menu>VI. Open the file "app -> res -> values -> strings.xml", and add 2 strings into it:
<resources>
...
<string name="mi_settings_title">Settings</string>
<string name="mi_about_title">About</string>
</resources>VII. Open the file "app -> res -> values -> string.xml (zh)", and add 2 strings into it:
...
<string name="mi_settings_title">设置</string>
<string name="mi_about_title">关于</string>
</resources>VIII. Override related functions in the main activity:
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.miSettings:
Intent intent = new Intent();
intent.setClass(MainActivity.this, SettingsActivity.class);
this.startActivity(intent);
break;
case R.id.miAbout:
Toast.makeText(this, "About", Toast.LENGTH_SHORT).show();
break;
}
return super.onOptionsItemSelected(item);
}IX: Done.
2. Add an activity which allows user to change the current language of the application.
I. Right click on the item "app -> java -> com.casperlee.personalexpense", select "New -> Activity -> Empty activity" from the popped menu, a dialog will be popped up:
II. Type in "SettingsActivity" as the activity name, leave other options to the default, and click "Finish" to create a new activity.
III. When creating the activity, Android Studio also created the layout file "activity_settings.xml" which is used by "SettingsActivity". Open the file "activity_settings.xml" in the project view, and put the following text in:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_settings"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#FF000000"
android:gravity="center_horizontal"
tools:context="com.casperlee.personalexpense.SettingsActivity">
<LinearLayout
android:id="@+id/layout0"
android:orientation="horizontal"
android:paddingTop="8dp"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center">
<Button
android:id="@+id/btn_apply"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1.0"
android:text="@string/btn_apply_caption" />
<Button
android:id="@+id/btn_cancel"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1.0"
android:text="@string/btn_cancel_caption" />
</LinearLayout>
<LinearLayout
android:id="@+id/layout1"
android:orientation="horizontal"
android:paddingTop="8dp"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@id/layout0">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1.0"
android:text="@string/text_language_caption"
android:gravity="right"
android:layout_gravity="center"
android:paddingRight="@dimen/activity_horizontal_margin"
android:textColor="@color/colorWhite" />
<LinearLayout
android:id="@+id/layout_language"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_weight="1.0">
<RadioGroup
android:id="@+id/rg_languages"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<RadioButton
android:id="@+id/rb_english"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="English"
android:textColor="@color/colorWhite" />
<RadioButton
android:id="@+id/rb_chinese"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="中文"
android:textColor="@color/colorWhite" />
<RadioButton
android:id="@+id/rb_default"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@string/rb_default_caption"
android:textColor="@color/colorWhite" />
</RadioGroup>
</LinearLayout>
</LinearLayout>
</RelativeLayout>IV. Open the file "app -> res -> values -> colors.xml" in the project view, add a color into it:
<?xml version="1.0" encoding="utf-8"?>
<resources>
...
<color name="colorWhite">#FFFFFF</color>
</resources>V. Open the file "app -> res -> values -> strings.xml", and add several strings into it:
<resources>
...
<string name="btn_apply_caption">Apply</string>
<string name="btn_cancel_caption">Cancel</string>
<string name="text_language_caption">Language</string>
<string name="rb_default_caption">Default</string>
</resources>VI. Open the file "app -> res -> values -> string.xml (zh)", and add several strings into it:
<?xml version="1.0" encoding="utf-8"?>
<resources>
...
<string name="btn_apply_caption">应用</string>
<string name="btn_cancel_caption">取消</string>
<string name="text_language_caption">语言</string>
<string name="rb_default_caption">默认</string>
</resources>VII. Open the file "app -> java -> com.casperlee.personalexpense -> SettingsActivity", and put the following code in:
package com.casperlee.personalexpense;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.Toast;
import com.casperlee.personalexpense.bll.AppParamBll;
public class SettingsActivity extends AppCompatActivity {
private Layout ui;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_settings);
this.ui = new Layout();
this.initSettings();
this.setListeners();
}
private void initSettings() {
switch (AppParamBll.getInstance().getAppLanguage()) {
case 0:
this.ui.rgLanguages.check(R.id.rb_english);
break;
case 1:
this.ui.rgLanguages.check(R.id.rb_chinese);
break;
default:
this.ui.rgLanguages.check(R.id.rb_default);
break;
}
}
private void setListeners() {
OnMyClickListener listener = new OnMyClickListener();
this.ui.btnApply.setOnClickListener(listener);
this.ui.btnCancel.setOnClickListener(listener);
}
private void performApplyButtonClick() throws Exception {
int language = 0;
switch (this.ui.rgLanguages.getCheckedRadioButtonId()) {
case R.id.rb_english:
language = 0;
break;
case R.id.rb_chinese:
language = 1;
break;
default:
language = 2;
break;
}
AppParamBll.getInstance().setAppLanguage(language);
this.finish();
}
private void performCancelButtonClick() {
this.finish();
}
private class Layout {
private Button btnApply;
private Button btnCancel;
private RadioGroup rgLanguages;
private RadioButton rbEnglish;
private RadioButton rbChinese;
private RadioButton rbDefault;
public Layout() {
this.initialize();
}
private void initialize() {
this.btnApply = (Button) findViewById(R.id.btn_apply);
this.btnCancel = (Button) findViewById(R.id.btn_cancel);
this.rgLanguages = (RadioGroup) findViewById(R.id.rg_languages);
this.rbEnglish = (RadioButton) findViewById(R.id.rb_english);
this.rbChinese = (RadioButton) findViewById(R.id.rb_chinese);
this.rbDefault = (RadioButton) findViewById(R.id.rb_default);
}
}
private class OnMyClickListener implements View.OnClickListener {
@Override
public void onClick(View v) {
try {
if (v == SettingsActivity.this.ui.btnApply) {
SettingsActivity.this.performApplyButtonClick();
} else if (v == SettingsActivity.this.ui.btnCancel) {
SettingsActivity.this.performCancelButtonClick();
}
}
catch (Exception e) {
Toast.makeText(SettingsActivity.this, e.getMessage(), Toast.LENGTH_LONG);
}
}
}
}VIII. Open the file "app -> java -> com.casperlee.personalexpense -> bll -> AppParamBll", and add a few functions:
...
private static final String Language = "Language";
...
public int getAppLanguage() {
String paramValue = this.dal.GetParamValue(Language, "2");
int result = Integer.parseInt(paramValue);
if (result < 0 || result > 2) {
result = 2;
}
return result;
}
public void setAppLanguage(int aLanguage) throws Exception {
if (aLanguage < 0 || aLanguage > 2) {
throw new Exception("The parameter is invalid!");
}
String paramValue = Integer.toString(aLanguage);
if (!this.dal.UpdateParam(Language, paramValue)) {
this.dal.AddParam(Language, paramValue);
}
}IX: Done.
Change the language when user starts the application
1. Open the file "app -> java -> com.casperlee.personalexpense -> MainActivity", add the following code into it:
...
import android.content.res.Configuration;
import android.content.res.Resources;
import android.util.DisplayMetrics;
import java.util.Locale;
public class MainActivity extends AppCompatActivity {
...
private void setLanguage(int aLanguage) {
Resources r = this.getResources();
final Configuration c = r.getConfiguration();
DisplayMetrics dm = r.getDisplayMetrics();
switch (aLanguage) {
case 0:
c.locale = Locale.ENGLISH;
break;
case 1:
c.locale = Locale.CHINESE;
break;
default:
c.locale = Locale.getDefault();
break;
}
r.updateConfiguration(c, dm);
}
@Override
protected void onCreate(Bundle savedInstanceState) {
...
this.setLanguage(AppParamBll.getInstance().getAppLanguage());
this.setTitle(R.string.app_name);
}2. Open the file "app -> manifests -> AndroidManifest.xml", and add the following text into it:
<uses-permission android:name="android.permission.CHANGE_CONFIGURATION" />
<application
...
android:configChanges="locale"
...3. Done!