transdroid/app/src/main/java/org/transdroid/core/gui/settings/KeyBoundPreferencesActivity.java

/*
 * Copyright 2010-2018 Eric Kok et al.
 *
 * Transdroid is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Transdroid is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Transdroid.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.transdroid.core.gui.settings;

import android.content.SharedPreferences;
import android.content.SharedPreferences.OnSharedPreferenceChangeListener;
import android.text.TextUtils;

import androidx.preference.CheckBoxPreference;
import androidx.preference.EditTextPreference;
import androidx.preference.ListPreference;
import androidx.preference.Preference;
import androidx.preference.PreferenceManager;
import androidx.preference.PreferenceScreen;

import org.androidannotations.annotations.EActivity;
import org.androidannotations.annotations.Extra;

import java.util.HashMap;
import java.util.Map;

/**
 * Abstract activity that helps implement a preference screen for key-bound settings, i.e. settings of which there can
 * be multiple and which are identified by an ascending order number/unique key. A typical implementation calls
 * {@link #init(int, int)} during the {@link #onCreate(android.os.Bundle)} (but after calling super.onCreate(Bundle))
 * and then call initXPreference for each contained preference. {@link #onPreferencesChanged()} can be overridden to
 * react to preference changes, e.g. when field availability should be updated (and where preference dependency isn't
 * enough).
 *
 * @author Eric Kok
 */
@EActivity
public abstract class KeyBoundPreferencesActivity extends PreferenceCompatActivity {

    @Extra
    protected int key = -1;

    private SharedPreferences sharedPrefs;
    private Map<String, String> originalSummaries = new HashMap<>();

    /**
     * Should be called during the activity {@link #onCreate(android.os.Bundle)} (but after super.onCreate(Bundle)) to
     * load the preferences for this screen from an XML resource.
     *
     * @param preferencesResId The XML resource to read preferences from, which may contain embedded
     *                         {@link PreferenceScreen} objects
     * @param currentMaxKey    The value of what is currently the last defined settings object, or -1 of no settings were
     *                         defined so far at all
     */
    protected final void init(int preferencesResId, int currentMaxKey) {

        // Load the raw preferences to show in this screen
        addPreferencesFromResource(preferencesResId);
        sharedPrefs = PreferenceManager.getDefaultSharedPreferences(this);

        // If no key was supplied (in the extra bundle) then use a new key instead
        if (key < 0) {
            key = currentMaxKey + 1;
        }

    }

    protected void onResume() {
        super.onResume();
        // Monitor preference changes
        PreferenceManager.getDefaultSharedPreferences(this).registerOnSharedPreferenceChangeListener(
                onPreferenceChangeListener);
    }

    protected void onPause() {
        super.onPause();
        // Stop monitoring preference changes
        PreferenceManager.getDefaultSharedPreferences(this).unregisterOnSharedPreferenceChangeListener(
                onPreferenceChangeListener);
    }

    private OnSharedPreferenceChangeListener onPreferenceChangeListener = new OnSharedPreferenceChangeListener() {
        @Override
        public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
            showValueOnSummary(key);
            onPreferencesChanged();
        }
    };

    /**
     * Key-bound preference activities may override this method if they want to react to preference changes.
     */
    protected void onPreferencesChanged() {
    }

    /**
     * Updates a preference that allows for text entry via a dialog. This is used for both string and integer values. No
     * default value will be shown.
     *
     * @param baseName The base name of the stored preference, e.g. item_name, which will then actually be stored under
     *                 item_name_[key]
     * @return The concrete {@link EditTextPreference} that is bound to this preference
     */
    protected final EditTextPreference initTextPreference(String baseName) {
        return initTextPreference(baseName, null);
    }

    /**
     * Updates a preference that allows for text entry via a dialog. This is used for both string and integer values.
     *
     * @param baseName The base name of the stored preference, e.g. item_name, which will then actually be stored under
     *                 item_name_[key]
     * @param defValue The default value for this preference, as shown when no value was yet stored
     * @return The concrete {@link EditTextPreference} that is bound to this preference
     */
    protected final EditTextPreference initTextPreference(String baseName, String defValue) {
        return initTextPreference(baseName, defValue, null);
    }

    /**
     * Updates a preference (including dependency) that allows for text entry via a dialog. This is used for both string
     * and integer values.
     *
     * @param baseName   The base name of the stored preference, e.g. item_name, which will then actually be stored under
     *                   item_name_[key]
     * @param defValue   The default value for this preference, as shown when no value was yet stored
     * @param dependency The base name of the preference to which this preference depends
     * @return The concrete {@link EditTextPreference} that is bound to this preference
     */
    protected final EditTextPreference initTextPreference(String baseName, String defValue, String dependency) {
        // Update the loaded Preference with the actual preference key to load/store with
        EditTextPreference pref = (EditTextPreference) findPreference(baseName);
        pref.setKey(baseName + "_" + key);
        pref.setDependency(dependency == null ? null : dependency + "_" + key);
        // Update the Preference by loading the current stored value into the EditText, if it exists
        pref.setText(sharedPrefs.getString(baseName + "_" + key, defValue));
        // Remember the original descriptive summary and if we have a value, show that instead
        originalSummaries.put(baseName + "_" + key, pref.getSummary() == null ? null : pref.getSummary().toString());
        showValueOnSummary(baseName + "_" + key);
        return pref;
    }

    /**
     * Updates a preference that simply shows a check box. No default value will be shown.
     *
     * @param baseName The base name of the stored preference, e.g. item_name, which will then actually be stored under
     *                 item_name_[key]
     * @return The concrete {@link CheckBoxPreference} that is bound to this preference
     */
    protected final CheckBoxPreference initBooleanPreference(String baseName) {
        return initBooleanPreference(baseName, false);
    }

    /**
     * Updates a preference that simply shows a check box.
     *
     * @param baseName The base name of the stored preference, e.g. item_name, which will then actually be stored under
     *                 item_name_[key]
     * @param defValue The default value for this preference, as shown when no value was yet stored
     * @return The concrete {@link CheckBoxPreference} that is bound to this preference
     */
    protected final CheckBoxPreference initBooleanPreference(String baseName, boolean defValue) {
        return initBooleanPreference(baseName, defValue, null);
    }

    /**
     * Updates a preference (including dependency) that simply shows a check box.
     *
     * @param baseName   The base name of the stored preference, e.g. item_name, which will then actually be stored under
     *                   item_name_[key]
     * @param defValue   The default value for this preference, as shown when no value was yet stored
     * @param dependency The base name of the preference to which this preference depends
     * @return The concrete {@link CheckBoxPreference} that is bound to this preference
     */
    protected final CheckBoxPreference initBooleanPreference(String baseName, boolean defValue, String dependency) {
        // Update the loaded Preference with the actual preference key to load/store with
        CheckBoxPreference pref = (CheckBoxPreference) findPreference(baseName);
        pref.setKey(baseName + "_" + key);
        pref.setDependency(dependency == null ? null : dependency + "_" + key);
        // Update the Preference by loading the current stored value into the Checkbox, if it exists
        pref.setChecked(sharedPrefs.getBoolean(baseName + "_" + key, defValue));
        return pref;
    }

    /**
     * Updates a preference that allows picking an item from a list. No default value will be shown.
     *
     * @param baseName The base name of the stored preference, e.g. item_name, which will then actually be stored under
     *                 item_name_[key]
     * @return The concrete {@link ListPreference} that is bound to this preference
     */
    protected final ListPreference initListPreference(String baseName) {
        return initListPreference(baseName, null);
    }

    /**
     * Updates a preference that allows picking an item from a list.
     *
     * @param baseName The base name of the stored preference, e.g. item_name, which will then actually be stored under
     *                 item_name_[key]
     * @param defValue The default value for this preference, as shown when no value was yet stored
     * @return The concrete {@link ListPreference} that is bound to this preference
     */
    protected final ListPreference initListPreference(String baseName, String defValue) {
        // Update the loaded Preference with the actual preference key to load/store with
        ListPreference pref = (ListPreference) findPreference(baseName);
        pref.setKey(baseName + "_" + key);
        // Update the Preference by selecting the current stored value in the list, if it exists
        pref.setValue(sharedPrefs.getString(baseName + "_" + key, defValue));
        // Remember the original descriptive summary and if we have a value, show that instead
        originalSummaries.put(baseName + "_" + key, pref.getSummary() == null ? null : pref.getSummary().toString());
        showValueOnSummary(baseName + "_" + key);
        return pref;
    }

    protected void showValueOnSummary(String prefKey) {
        Preference pref = findPreference(prefKey);
        if (sharedPrefs.contains(prefKey)
                && pref instanceof EditTextPreference
                && !TextUtils.isEmpty(sharedPrefs.getString(prefKey, ""))
                && !isPasswordPref((EditTextPreference) pref)) {
            // Non-password edit preferences show the user-entered value
            pref.setSummary(sharedPrefs.getString(prefKey, ""));
            return;
        } else if (sharedPrefs.contains(prefKey) && pref instanceof ListPreference
                && ((ListPreference) pref).getValue() != null) {
            // List preferences show the selected list value
            ListPreference listPreference = (ListPreference) pref;
            pref.setSummary(listPreference.getEntries()[listPreference.findIndexOfValue(listPreference.getValue())]);
            return;
        }
        if (originalSummaries.containsKey(prefKey))
            pref.setSummary(originalSummaries.get(prefKey));
    }

    protected boolean isPasswordPref(EditTextPreference preference) {
        return preference.getKey().startsWith("server_pass_") || preference.getKey().startsWith("server_extrapass")
                || preference.getKey().startsWith("server_ftppass");
    }

}