android.preference.PreferenceScreen#getSharedPreferences ( )源码实例Demo

@Override
public void setStringFieldSummary(String fieldName) {
    PreferenceScreen pfs = getPreferenceScreen();
    SharedPreferences sp = pfs.getSharedPreferences();
    Preference pref = pfs.findPreference(fieldName);

    String val = sp.getString(fieldName, null);
    if (TextUtils.isEmpty(val)) {
        val = getDefaultFieldSummary(fieldName);
    }
    setPreferenceSummary(pref, val);
}
 

/**
 * Set summary of a standard string field If empty will display the default
 * summary Else it displays the preference value
 * 
 * @param fieldName the preference key name
 */
public void setStringFieldSummary(String fieldName) {
    PreferenceScreen pfs = getPreferenceScreen();
    SharedPreferences sp = pfs.getSharedPreferences();
    Preference pref = pfs.findPreference(fieldName);

    String val = sp.getString(fieldName, null);
    if (TextUtils.isEmpty(val)) {
        val = getDefaultFieldSummary(fieldName);
    }
    setPreferenceSummary(pref, val);
}
 

/**
 * Set summary of a password field If empty will display default summary If
 * password will display a * char for each letter of password
 * 
 * @param fieldName the preference key name
 */
public void setPasswordFieldSummary(String fieldName) {
    PreferenceScreen pfs = getPreferenceScreen();
    SharedPreferences sp = pfs.getSharedPreferences();
    Preference pref = pfs.findPreference(fieldName);

    String val = sp.getString(fieldName, null);

    if (TextUtils.isEmpty(val)) {
        val = getDefaultFieldSummary(fieldName);
    } else {
        val = val.replaceAll(".", "*");
    }
    setPreferenceSummary(pref, val);
}
 

public static SharedPreferences getSharedPreferences(PreferenceManager preferenceManager, PreferenceScreen preferenceScreen) {
    preferenceManager.setSharedPreferencesMode(Context.MODE_WORLD_READABLE);
    return preferenceScreen.getSharedPreferences();
}
 

@Override
protected void onResume() {
    super.onResume();
    showRecentChanges();
    PreferenceScreen screen = getPreferenceScreen();
    SharedPreferences sharedPreferences = screen.getSharedPreferences();

    // Hide preferences for certain widget sizes
    int widgetSize = sharedPreferences.getInt("widgetSize", 0);

    // Remove extra stocks
    if (widgetSize == 0 || widgetSize == 1) {
        PreferenceScreen stock_setup = (PreferenceScreen) findPreference("stock_setup");
        for (int i = 5; i < 11; i++)
            removePref(stock_setup, "Stock" + i);
    }
    // Remove extra widget views
    if (widgetSize == 1 || widgetSize == 3) {
        PreferenceScreen widget_views = (PreferenceScreen) findPreference("widget_views");
        removePref(widget_views, "show_percent_change");
        removePref(widget_views, "show_portfolio_change");
        removePref(widget_views, "show_profit_daily_change");
        removePref(widget_views, "show_profit_change");
    }
    // Hide Feedback option if not relevant
    String install_date = getAppPreferences().getString("install_date", null);
    if (DateTools.elapsedDays(install_date) < 30)
        removePref("about_menu", "rate_app");

    // Initialise the summaries when the preferences screen loads
    Map<String, ?> map = sharedPreferences.getAll();
    for (String key : map.keySet())
        updateSummaries(sharedPreferences, key);

    // Update version number
    findPreference("version").setSummary("BUILD " + VersionTools.BUILD);

    // Force update of global preferences
    // TODO Ensure the items below are included in the above list
    // rather than updating these items twice (potentially)
    updateSummaries(sharedPreferences, "update_interval");
    updateSummaries(sharedPreferences, "update_start");
    updateSummaries(sharedPreferences, "update_end");
    updateSummaries(sharedPreferences, "update_weekend");

    // Set up a listener whenever a key changes
    sharedPreferences.registerOnSharedPreferenceChangeListener(this);
}