GitNex/app/src/main/java/org/mian/gitnex/helpers/TinyDB.java

package org.mian.gitnex.helpers;

import android.content.Context;
import android.content.SharedPreferences;
import android.graphics.Bitmap;
import android.graphics.Bitmap.CompressFormat;
import android.os.Environment;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Map;

/**
 * @author M M Arif
 */
public class TinyDB {

	private static volatile TinyDB tinyDB;

    private final SharedPreferences preferences;

	private TinyDB(Context appContext) {
        preferences = appContext.getSharedPreferences(appContext.getPackageName() + "_preferences", Context.MODE_PRIVATE);
    }

	public static synchronized TinyDB getInstance(Context context) {

		if(tinyDB == null) {
			synchronized(TinyDB.class) {
				if(tinyDB == null) {
					tinyDB = new TinyDB(context);
				}
			}
		}

		return tinyDB;

	}

    /**
     * Saves 'theBitmap' into 'fullPath'
     * @param fullPath full path of the image file e.g. "Images/MeAtLunch.png"
     * @param theBitmap the image you want to save as a Bitmap
     * @return true if image was saved, false otherwise
     */
    public boolean putImageWithFullPath(String fullPath, Bitmap theBitmap) {
        return !(fullPath == null || theBitmap == null) && saveBitmap(fullPath, theBitmap);
    }

    /**
     * Saves the Bitmap as a PNG file at path 'fullPath'
     * @param fullPath path of the image file
     * @param bitmap the image as a Bitmap
     * @return true if it successfully saved, false otherwise
     */
    private boolean saveBitmap(String fullPath, Bitmap bitmap) {
        if (fullPath == null || bitmap == null)
            return false;

        boolean fileCreated = false;
        boolean bitmapCompressed = false;
        boolean streamClosed = false;

        File imageFile = new File(fullPath);

        if (imageFile.exists())
            if (!imageFile.delete())
                return false;

        try {
            fileCreated = imageFile.createNewFile();
        } catch (IOException e) {
            e.printStackTrace();
        }

        FileOutputStream out = null;
        try {
            out = new FileOutputStream(imageFile);
            bitmapCompressed = bitmap.compress(CompressFormat.PNG, 100, out);

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (out != null) {
                try {
                    out.flush();
                    out.close();
                    streamClosed = true;
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

        return (fileCreated && bitmapCompressed && streamClosed);
    }

    // Getters

    /**
     * Get int value from SharedPreferences at 'key'. If key not found, return 'defaultValue'
     * @param key SharedPreferences key
     * @return int value at 'key' or 'defaultValue' if key not found
     */
    public int getInt(String key) {
        return preferences.getInt(key, 0);
    }

    public int getInt(String key, int defaultValue) {
        return preferences.getInt(key, defaultValue);
    }

    /**
     * Get long value from SharedPreferences at 'key'. If key not found, return 'defaultValue'
     * @param key SharedPreferences key
     * @param defaultValue long value returned if key was not found
     * @return long value at 'key' or 'defaultValue' if key not found
     */
    public long getLong(String key, long defaultValue) {
        return preferences.getLong(key, defaultValue);
    }

    /**
     * Get float value from SharedPreferences at 'key'. If key not found, return 'defaultValue'
     * @param key SharedPreferences key
     * @return float value at 'key' or 'defaultValue' if key not found
     */
    public float getFloat(String key) {
        return preferences.getFloat(key, 0);
    }

    public float getFloat(String key, float defaultValue) {
        return preferences.getFloat(key, defaultValue);
    }

    /**
     * Get String value from SharedPreferences at 'key'. If key not found, return ""
     * @param key SharedPreferences key
     * @return String value at 'key' or "" (empty String) if key not found
     */
    public String getString(String key) {
        return preferences.getString(key, "");
    }

    public String getString(String key, String defaultValue) {
        return preferences.getString(key, defaultValue);
    }

    /**
     * Get boolean value from SharedPreferences at 'key'. If key not found, return 'defaultValue'
     * @param key SharedPreferences key
     * @return boolean value at 'key' or 'defaultValue' if key not found
     */
    public boolean getBoolean(String key) {
        return preferences.getBoolean(key, false);
    }

    public boolean getBoolean(String key, boolean defaultValue) {
        return preferences.getBoolean(key, defaultValue);
    }

    // Put methods

    /**
     * Put int value into SharedPreferences with 'key' and save
     * @param key SharedPreferences key
     * @param value int value to be added
     */
    public void putInt(String key, int value) {
        checkForNullKey(key);
        preferences.edit().putInt(key, value).apply();
    }

    /**
     * Put long value into SharedPreferences with 'key' and save
     * @param key SharedPreferences key
     * @param value long value to be added
     */
    public void putLong(String key, long value) {
        checkForNullKey(key);
        preferences.edit().putLong(key, value).apply();
    }

    /**
     * Put float value into SharedPreferences with 'key' and save
     * @param key SharedPreferences key
     * @param value float value to be added
     */
    public void putFloat(String key, float value) {
        checkForNullKey(key);
        preferences.edit().putFloat(key, value).apply();
    }

    /**
     * Put String value into SharedPreferences with 'key' and save
     * @param key SharedPreferences key
     * @param value String value to be added
     */
    public void putString(String key, String value) {
        checkForNullKey(key); checkForNullValue(value);
        preferences.edit().putString(key, value).apply();
    }

    /**
     * Put boolean value into SharedPreferences with 'key' and save
     * @param key SharedPreferences key
     * @param value boolean value to be added
     */
    public void putBoolean(String key, boolean value) {
        checkForNullKey(key);
        preferences.edit().putBoolean(key, value).apply();
    }

    /**
     * Remove SharedPreferences item with 'key'
     * @param key SharedPreferences key
     */
    public void remove(String key) {
        preferences.edit().remove(key).apply();
    }

    /**
     * Delete image file at 'path'
     * @param path path of image file
     * @return true if it successfully deleted, false otherwise
     */
    public boolean deleteImage(String path) {
        return new File(path).delete();
    }


    /**
     * Clear SharedPreferences (remove everything)
     */
    public void clear() {
        preferences.edit().clear().apply();
    }

    /**
     * Retrieve all values from SharedPreferences. Do not modify collection return by method
     * @return a Map representing a list of key/value pairs from SharedPreferences
     */
    public Map<String, ?> getAll() {
        return preferences.getAll();
    }


    /**
     * Register SharedPreferences change listener
     * @param listener listener object of OnSharedPreferenceChangeListener
     */
    public void registerOnSharedPreferenceChangeListener(
            SharedPreferences.OnSharedPreferenceChangeListener listener) {

        preferences.registerOnSharedPreferenceChangeListener(listener);
    }

    /**
     * Unregister SharedPreferences change listener
     * @param listener listener object of OnSharedPreferenceChangeListener to be unregistered
     */
    public void unregisterOnSharedPreferenceChangeListener(
            SharedPreferences.OnSharedPreferenceChangeListener listener) {

        preferences.unregisterOnSharedPreferenceChangeListener(listener);
    }


    /**
     * Check if external storage is writable or not
     * @return true if writable, false otherwise
     */
    public static boolean isExternalStorageWritable() {
        return Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState());
    }

    /**
     * Check if external storage is readable or not
     * @return true if readable, false otherwise
     */
    public static boolean isExternalStorageReadable() {
        String state = Environment.getExternalStorageState();

        return Environment.MEDIA_MOUNTED.equals(state) ||
                Environment.MEDIA_MOUNTED_READ_ONLY.equals(state);
    }
    /**
     * null keys would corrupt the shared pref file and make them unreadable this is a preventive measure
     * @param key the pref key
     */
    public void checkForNullKey(String key) {
        if (key == null){
            throw new NullPointerException();
        }
    }
    /**
     * null keys would corrupt the shared pref file and make them unreadable this is a preventive measure
     * @param value the pref key
     */
    public void checkForNullValue(String value) {
        if (value == null){
            throw new NullPointerException();
        }
    }
}