从微调器值获取strings.xml中的字符串名称属性

Question

I have a spinner (like a comboBox) in my android app that selects the language you want to change, so the spinner displays only 3 languages from an array according to the current locale of the phone :

<string-array name="spinner_lang">
    <item>@string/lang_en</item>
    <item>@string/lang_fr</item>
    <item>@string/lang_jp</item>
</string-array>

Here is all of my strings.xml ressources files : http://i.stack.imgur.com/u667T.png

And when I click on my spinner, I can only get the raw value of the language, ie : English or French but what I need is getting the key name of the language, here it's " lang_en " or " lang_fr " because if I can't check this, I have to check nine times instead of 3, and if I want to change the value of the language, I have to change it to both spots.

I did a lot of research with the keywords "get name of a string value xml" and "how to get the locale of a string" and I found nothing, maybe it wasn't the good keywords. All I need is getting a string that I can convert to a Locale with forLanguageTag(String languageTag) to give in parameter to my function public void changeLanguage(Locale l) , so I can change the app locale with my spinner.

I'm running with Android Studio 1.3.2 on Windows 10.

I really hope some people will help me ^^

Answer 1

You are going to need a custom SpinnerAdapter .

First, let's establish our XML.

We'll use the string array only to define the order of the language list. We'll also define the correct language codes here.

In /res/values/strings.xml (ie not locale-specific):

<string-array name="spinner_lang">
    <item>en</item>
    <item>es</item>
    <item>fr</item>
</string-array>

<string-array name="spinner_lang_code">
    <item>code_en</item>
    <item>code_es</item>
    <item>code_fr</item>
</string-array>

<string name="code_en">en-US</string>
<string name="code_es">es-ES</string>
<string name="code_fr">fr-FR</string>

Now in your locale-specific string.xml files, we'll define the language names .

For example, in /res/values-en/strings.xml

<string name="en">English</string>
<string name="es">Spanish</string>
<string name="fr">French</string>

Let's make a simple (inner) class to hold our language data:

public static class Lang {
    String mCode;
    String mName;

    public Lang(String code, String name) {
        this.mCode = code;
        this.mName = name;
    }
}

Now we should have everything to code our adapter:

public static class LanguageSelectionAdapter extends BaseAdapter {

    private Lang[] mLangs;

    public LanguageSelectionAdapter(Context context) {

        Resources resources = context.getResources();

        String[] codes = resources.getStringArray(R.id.spinner_lang_code);
        String[] names = resources.getStringArray(R.id.spinner_lang);

        mLangs = new Lang[names.length];
        for (int i = 0; i < names.length; i++) {
            int codeRes = resources.getIdentifier(codes[i], "string", null);
            String code = resources.getString(codeRes);
            int nameRes = resources.getIdentifier(names[i], "string", null);
            String name = resources.getString(nameRes);
            mLangs[i] = new Lang(code, name);
        }
    }

    @Override
    public int getCount() {
        return mLangs == null ? 0 : mLangs.length;
    }

    @Override
    public Object getItem(int position) {
        return mLangs == null ? null : mLangs[position];
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public boolean hasStableIds() {
        return true;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        if (convertView == null) {
            convertView = LayoutInflater.from(parent.getContext()).inflate(android.R.layout.simple_list_item_1, parent, false);
        }

        TextView text1 = (TextView) convertView.findViewById(android.R.id.text1);
        text1.setText(mLangs[position].mName);

        return convertView;
    }
}

Now when someone selects an item from the Spinner , you need to get the language code based on the language name they selected:

spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
        LanguageSelectionAdapter adapter = (LanguageSelectionAdapter) parent.getAdapter();
        Lang lang = (Lang) adapter.getItem(position);
        String langCode = lang.mCode;
        Locale locale = Locale.forLanguageTag(langCode);

        // ... switch your Locale here
    }

    @Override
    public void onNothingSelected(AdapterView<?> parent) {
    }
});

Answer 2

Well, I tried to use your code into my app, It wasn't working so I re-created another project, I used your code but there was some errors :

I had an error message on setOnItemSelectedListener that was "Cannot resolve symbol 'setOnItemSelectedListener'", so I added a implements AdapterView.OnItemSelectedListener after the class name and I removed spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() .

The String[] codes = resources.getStringArray(R.id.spinner_lang_code); and the same for the String[] names weren't working, so I replaced it with R.array.spinner_lang_code and R.array.spinner_lang .

I also added the values you mentioned in the /res/values/strings.xml and /res/values-en/strings.xml .

I tried to fix these errors, but the following code (without any errors according to android studio) was crashing my app at launch :

package com.example.nicolas.labo1;

import android.annotation.TargetApi;
import android.content.Context;
import android.content.res.Configuration;
import android.content.res.Resources;
import android.os.Build;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.BaseAdapter;
import android.widget.Spinner;
import android.widget.TextView;

import java.util.Locale;

public class MainActivity extends AppCompatActivity implements AdapterView.OnItemSelectedListener{
    Spinner spinner;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        spinner = (Spinner) findViewById(R.id.spinner);

        ArrayAdapter adapter = ArrayAdapter.createFromResource(this, R.array.spinner_lang, android.R.layout.simple_spinner_item);
        spinner.setAdapter(adapter);
        spinner.setOnItemSelectedListener(this);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @Override
    public void onResume(){
        super.onResume();
        changeLanguage();
    }

    public void changeLanguage(){
        Locale loc = new Locale(Locale.getDefault().toString());
        Configuration config = getBaseContext().getResources().getConfiguration();
        Configuration conf = new Configuration(config);
        conf.locale = loc;
        getBaseContext().getResources().updateConfiguration(conf, getBaseContext().getResources().getDisplayMetrics());
    }

    public void changeLanguage(Locale l){
        Locale loc = new Locale(l.toString());
        Configuration config = getBaseContext().getResources().getConfiguration();
        Configuration conf = new Configuration(config);
        conf.locale = loc;
        getBaseContext().getResources().updateConfiguration(conf, getBaseContext().getResources().getDisplayMetrics());
    }

    public static class Lang {
        String mCode;
        String mName;

        public Lang(String code, String name) {
            this.mCode = code;
            this.mName = name;
        }
    }

    public static class LanguageSelectionAdapter extends BaseAdapter {

        private Lang[] mLangs;

        public LanguageSelectionAdapter(Context context) {

            Resources resources = context.getResources();

            String[] codes = resources.getStringArray(R.array.spinner_lang_code);
            String[] names = resources.getStringArray(R.array.spinner_lang);

            mLangs = new Lang[names.length];
            for (int i = 0; i < names.length; i++) {
                int codeRes = resources.getIdentifier(codes[i], "string", null);
                String code = resources.getString(codeRes);
                int nameRes = resources.getIdentifier(names[i], "string", null);
                String name = resources.getString(nameRes);
                mLangs[i] = new Lang(code, name);
            }
        }

        @Override
        public int getCount() {
            return mLangs == null ? 0 : mLangs.length;
        }

        @Override
        public Object getItem(int position) {
            return mLangs == null ? null : mLangs[position];
        }

        @Override
        public long getItemId(int position) {
            return position;
        }

        @Override
        public boolean hasStableIds() {
            return true;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {

            if (convertView == null) {
                convertView = LayoutInflater.from(parent.getContext()).inflate(android.R.layout.simple_list_item_1, parent, false);
            }

            TextView text1 = (TextView) convertView.findViewById(android.R.id.text1);
            text1.setText(mLangs[position].mName);

            return convertView;
        }
    }

    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
        LanguageSelectionAdapter adapter = (LanguageSelectionAdapter) parent.getAdapter();
        Lang lang = (Lang) adapter.getItem(position);
        String langCode = lang.mCode;
        Locale locale = Locale.forLanguageTag(langCode);

        changeLanguage(locale);
    }

    @Override
    public void onNothingSelected(AdapterView<?> parent) {
    }
}

But it's my first time with android and java, I had the first lesson Friday at school, so I'm not really at ease with some things that you can consider as "basics", so I'm sorry if I do some huge mistakes ^^