Android Config File

Question

What is the best way and how to set up a config file for a application?

I want the application to be able to look into a text file on the sd card and pick out certa

Answer 1

I met such requirement recently, noting down here, how I did it.

the application to be able to look into a text file on the sd card and pick out certain information that it requires

Requirement:

1. Configuration value(score_threshold) has to be available at the sdcard. So somebody can change the values after releasing the apk.
2. The config file must be available at the "/sdcard/config.txt" of the android hardware.

The config.txt file contents are,

score_threshold=60

Create a utility class Config.java, for reading and writing text file.

import android.util.Log;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Properties;

public final class Config {

    private static final String TAG = Config.class.getSimpleName();
    private static final String FILE_PATH = Environment.getExternalStorageDirectory().getAbsolutePath() + "/config.txt";
    private static Config sInstance = null;

    /**
     * Gets instance.
     *
     * @return the instance
     */
    public static Config getInstance() {
        if (sInstance == null) {
            synchronized (Config.class) {
                if (sInstance == null) {
                    sInstance = new Config();
                }
            }
        }
        return sInstance;
    }

    /**
     * Write configurations values boolean.
     *
     * @return the boolean
     */
    public boolean writeConfigurationsValues() {

        try (OutputStream output = new FileOutputStream(FILE_PATH)) {

            Properties prop = new Properties();

            // set the properties value
            prop.setProperty("score_threshold", "60");

            // save properties
            prop.store(output, null);

            Log.i(TAG, "Configuration stored  properties: " + prop);
            return true;
        } catch (IOException io) {
            io.printStackTrace();
            return false;
        }
    }

    /**
     * Get configuration value string.
     *
     * @param key the key
     * @return the string
     */
    public String getConfigurationValue(String key){
        String value = "";
        try (InputStream input = new FileInputStream(FILE_PATH)) {

            Properties prop = new Properties();

            // load a properties file
            prop.load(input);
            value = prop.getProperty(key);
            Log.i(TAG, "Configuration stored  properties value: " + value);
         } catch (IOException ex) {
            ex.printStackTrace();
        }
        return value;
    }
}

Create another utility class to write the configuration file for the first time execution of the application, Note: SD card read/write permission has to be set for the application.

public class ApplicationUtils {

  /**
  * Sets the boolean preference value
  *
  * @param context the current context
  * @param key     the preference key
  * @param value   the value to be set
  */
 public static void setBooleanPreferenceValue(Context context, String key, boolean value) {
     SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(context);
     sp.edit().putBoolean(key, value).commit();
 }

 /**
  * Get the boolean preference value from the SharedPreference
  *
  * @param context the current context
  * @param key     the preference key
  * @return the the preference value
  */
 public static boolean getBooleanPreferenceValue(Context context, String key) {
     SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(context);
     return sp.getBoolean(key, false);
 }

}

At your Main Activity, onCreate()

if(!ApplicationUtils.getBooleanPreferenceValue(this,"isFirstTimeExecution")){
           Log.d(TAG, "First time Execution");
           ApplicationUtils.setBooleanPreferenceValue(this,"isFirstTimeExecution",true);
           Config.getInstance().writeConfigurationsValues();
}
// get the configuration value from the sdcard.
String thresholdScore = Config.getInstance().getConfigurationValue("score_threshold");
Log.d(TAG, "thresholdScore from config file is : "+thresholdScore );