Android Tutorial - Android String Resources Format

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Plurals Resource

The resource plurals has a list of strings for expressing a numerical quantity in various ways.

For example:

• There is 1 student.
• There are 2 students.
• There are 20 students.

Android allows you to represent this variation as a plurals resource.

The following example shows how you would represent these two variations based on quantity in a resource file.

<resources...>
   <plurals name="my_text">
      <item quantity="one">There is 1 student</item>
      <item quantity="other">There are %d students</item>
   </plurals>
</resources>

The first parameter to the getQuantityString() method is the plurals resource ID. The second parameter selects the string to be used.

When the value of the quantity is 1, you use the string as is. When the value is not 1, you must supply a third parameter whose value is to be placed where %d is.

Resources res = your-activity.getResources();
String s1 = res.getQuantityString(R.plurals.my_text, 0,0);
String s2 = res.getQuantityString(R.plurals.my_text, 1,1);
String s3 = res.getQuantityString(R.plurals.my_text, 2,2);
String s4 = res.getQuantityString(R.plurals.my_text, 10,10);

Java format string

The Android string resource definitions allow standard Java string-formatting sequences.

The following code defines Java format string which we can use in the Java code.

This XML string resource file needs to be in the /res/values subdirectory.

<resources>
    <string name="simple_string">simple string</string>
    <string name="java_format_string">
           Hi %2$s Java format string. %1$s again
     </string>
</resources>

The following code shows how to use Java format string in Java code.

String simpleString = activity.getString(R.string.simple_string);
textView.setText(simpleString);

String javaFormatString = activity.getString(R.string.java_format_string);

String substitutedString = String.format(javaFormatString, "Hello" , "Android");

textView.setText(substitutedString);

java_format_string is defined in the resource xml file. We use the Activity.getString to load the string to Java code.

HTML strings

Android allows child XML elements such as <b>, <i>, and other simple text-formatting HTML within the <string> node.

You can use this compound HTML string to style the text before painting in a text view.

The following XML string resource file needs to be in the /res/values subdirectory.

<resources>
    <string name="simple_string">simple string</string>
     <string name="tagged_string">
         Hello <b><i>Android</i></b>, You are bold.
     </string>
</resources>

The following java code shows how to use the html-formatted string.

             
String simpleString = activity.getString(R.string.simple_string);
textView.setText(simpleString);

String htmlTaggedString = activity.getString(R.string.tagged_string);

Spanned textSpan = android.text.Html.fromHtml(htmlTaggedString);

textView.setText(textSpan);

HTML encode and decode

The following code shows how to use the utilities calss for HTML encode and decode.

Layout xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  >
  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    >
    <Button android:id="@+id/format"
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content"
      android:text="OK"
      />
    <EditText android:id="@+id/name"
      android:layout_width="fill_parent" 
      android:layout_height="wrap_content" 
      />
  </LinearLayout>
  <TextView android:id="@+id/result"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    />
</LinearLayout>

res/values/strings.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
  <string name="funky_format">My name is &lt;b&gt;%1$s&lt;/b&gt;</string>
</resources>

Java code

/***/* ww w .  j  a  va  2 s  .  c om*/
  Copyright (c) 2008-2009 CommonsWare, LLC
  
  Licensed under the Apache License, Version 2.0 (the "License"); you may
  not use this file except in compliance with the License. You may obtain
  a copy of the License at
    http://www.apache.org/licenses/LICENSE-2.0
  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
*/


import android.app.Activity;
import android.os.Bundle;
import android.text.TextUtils;
import android.text.Html;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends Activity {
  EditText name;
  TextView result;
  
  @Override
  public void onCreate(Bundle icicle) {
    super.onCreate(icicle);
    setContentView(R.layout.main);
    
    name=(EditText)findViewById(R.id.name);
    result=(TextView)findViewById(R.id.result);
    
    Button btn=(Button)findViewById(R.id.format);
    
    btn.setOnClickListener(new Button.OnClickListener() {
      public void onClick(View v) {
        applyFormat();
      }
    });
  }  
  private void applyFormat() {
    String format=getString(R.string.funky_format);
    String simpleResult=String.format(format,TextUtils.htmlEncode(name.getText().toString()));
    result.setText(Html.fromHtml(simpleResult));
  }
}

We use the TextUtils.htmlEncode method to do the html encoding.

Quoted strings

We can use Quoted strings in Android string resource file.

The quoted strings need to be either escaped or placed in alternate quotes.

The following XML string resource file needs to be in the /res/values subdirectory.

<resources>
    <string name="simple_string">simple string</string>
    <string name="quoted_string">"quoted 'xyz' string"</string>
    <string name="double_quoted_string">\"double quotes\"</string>
</resources>

The following java code shows how to use the resource file above.

String simpleString = activity.getString(R.string.simple_string);
textView.setText(simpleString);

String quotedString = activity.getString(R.string.quoted_string);
textView.setText(quotedString);

String doubleQuotedString = activity.getString(R.string.double_quoted_string);
textView.setText(doubleQuotedString);

From the code above we can see that there are two ways to add quotations to a string.

Use multiple string resource files

To see that multiple string resource files are allowed in this subdirectory, you can place another file with the following content in the same subdirectory and call it strings1.xml.

We can have one string resourde defined as follows.

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="hello">hello</string>
    <string name="app_name">hello appname</string>
</resources>

Example of an Additional strings.xml File.

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="hello1">hello 1</string>
    <string name="app_name1">hello appname 1</string>
</resources>

The Eclipse ADT plug-in validates the uniqueness of these IDs at compile time and places them in R.java as two additional constants: R.string.hello1 and R.string.app_name1.

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