Android Open Source - WeatherBar Prefs

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License

The source code is released under:

MIT License

Java Source Code

package com.cjbarker.wb;
//from   w w w  . ja v a2 s.c om
import com.cjbarker.wb.receiver.Connection;

import android.content.Context;
import android.content.SharedPreferences;
import android.os.Build;
import android.util.Log;

public class Prefs {
  
  private static Prefs SINGLETON = null;
  private static final String TAG = "Prefs";
  
  private Context ctx;
  private SharedPreferences prefs;
  
  private Prefs() {}
  
  /**
   * Constructor initializes shared preferences
   * @param ctx  Activity's Context
   */
  private Prefs(Context ctx) {
    Log.d(TAG, "Initializing SharedPreferences for " + ctx.getString(R.string.pref_file_key));
    this.prefs = ctx.getSharedPreferences(
        ctx.getString(R.string.pref_file_key), Context.MODE_PRIVATE);
    this.ctx = ctx;
  }

  /**
   * @return    Singleton previously instantiated
   * @exception  NullPointerException if did not call <code>getInstance(Context ctx)</code>
   */
  public static Prefs getInstance() {
    if (SINGLETON == null) {
      throw new NullPointerException("Must initialize with Context before invoking");
    }
    return SINGLETON;
  }
  
  /**
   * Initializes the SharedPrefence singleton. Is thread safe.
   * 
   * @param ctx  Activity's Context
   * @return    Singleton Prefs
   */
  public static Prefs getInstance(Context ctx) {
    if (ctx == null) {
      return null;
    }
    synchronized (SINGLETON) {
      if (SINGLETON == null) {
        SINGLETON = new Prefs(ctx);
      }
    }
    return SINGLETON;
  }
  
  /**
   * Gets shared preference value based on the requested key.
   * If no value is found the defaultValue is returned.
   * 
   * @param key    Object key to look-up shared preference
   * @param defValue  Default value to return when no key found
   * @return      SharedPreference value or default for key
   */
  public Object getValue(String key, Object defValue) {
    Object obj = null;
    
    if (key == null || key.trim().equals("") || defValue == null) { 
      return obj;
    }

    if (defValue instanceof String) {
      obj = prefs.getString(key, (String)defValue);
    }
    else if (defValue instanceof Integer) {
      obj = prefs.getInt(key, (Integer)defValue);
    }
    else if (defValue instanceof Boolean) {
      obj = prefs.getBoolean(key, (Boolean)defValue);
    }
    else if (defValue instanceof Float) {
      obj = prefs.getFloat(key, (Float)defValue);
    }
    else if (defValue instanceof Long) {
      obj = prefs.getFloat(key, (Long)defValue);
    }
    else {
      Log.w(TAG, "Unsupported SharedPrefs value type: " + defValue.getClass().getCanonicalName());
    }
    
    Log.d(TAG, "SharedPrefs Get " + key + ":" + obj);
    
    return obj;
  }
  
  /**
   * Puts the shared preference value based on the requested key.
   * 
   * @param key    Object key to store
   * @param value    Value to store
   */
  public void putValue(String key, Object value) {
    if (key == null || key.trim().equals("") || value == null) { 
      return;
    }
    
    SharedPreferences.Editor editor = prefs.edit();

    if (value instanceof String) {
      editor.putString(key, (String)value);
    }
    else if (value instanceof Integer) {
      editor.putInt(key, (Integer)value);
    }
    else if (value instanceof Boolean) {
      editor.putBoolean(key, (Boolean)value);
    }
    else if (value instanceof Float) {
      editor.putFloat(key, (Float)value);
    }
    else if (value instanceof Long) {
      editor.putLong(key, (Long)value);
    }
    else {
      Log.w(TAG, "Unsupported SharedPrefs Editor value type: " + value.getClass().getCanonicalName());
      return;
    }
    
    Log.d(TAG, "SharedPrefs Put " + key + ":" + value);
    
    // A slight performance improvement via async apply() vs. blocking on commit().
    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.GINGERBREAD) {
      editor.commit();
    } else { 
      editor.apply();
    }
  }
  
  /**
   * Setter for shared preference
   * 
   * @param value  Denotes battery state is good/healthy/okay
   */
  public void setBatteryOkay(boolean value) {
    this.putValue(ctx.getString(R.string.pref_battery_okay), value);
  }
  
  /**
   * @return  Boolean denoting whether or not battery state is good/healthy/okay
   */
  public boolean isBatteryOkay() {
    return (Boolean)this.getValue(ctx.getString(R.string.pref_battery_okay), Boolean.TRUE);
  }
  
  /**
   * @return  Boolean denoting whether or not okay to query weather based on device state
   */
  public boolean isOkayToQuery() {
    boolean okay = (Boolean)this.getValue(ctx.getString(R.string.pref_okay_to_query), Boolean.TRUE);
    return (okay && isBatteryOkay() && Connection.isNetworkConnected(this.ctx));
  }
  
  /**
   * Setter for shared preference 
   * 
   * @param value  Denotes whether or not okay to query weather based on device state
   */
  public void setOkayToQuery(boolean value) {
    this.putValue(ctx.getString(R.string.pref_okay_to_query), value);
  }
  
  /**
   * Setter for shared preference 
   * 
   * @param freq  Denotes update frequency in milliseconds for how often to check weather
   */
  public void setUpdateFrequency(long freq) {
    this.putValue(ctx.getString(R.string.pref_update_freq), freq);
  }
  
  /**
   * Setter for shared preference
   * 
   * @param lastUpdate  Denotes datetime last successful weather update occurred
   */
  public void setLastWeatherUpdate(long lastUpdate) {
    if (lastUpdate <= 0) {
      return;
    }
    this.putValue(ctx.getString(R.string.pref_last_weather_update), lastUpdate);
  }
  
  /**
   * Denotes whether or not the last successful weather update has expired based on
   * the update frequency.
   * 
   * @return  True if expired and weather should refresh via query
   */
  public boolean isUpdateExpired() {
    long curr = System.currentTimeMillis();
    long lastUpdate = (Long)this.getValue(ctx.getString(R.string.pref_last_weather_update), 0);
    long diff = curr - lastUpdate;
    long freq = (Long)this.getValue(ctx.getString(R.string.pref_update_freq), 0);
    return (diff >= freq);
  }
}

Java Source Code List

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