Preference Screen Custom Layout only works with second click

Question

I have a preference screen using a 'custom layout':

android:layout="@layout/currencycodes"

This issue is it fails to bring up the layout on the first attempt. As you see from the animated gif below, I have to retreat and try again a second time for the layout to come up. Now why is that?

preferences.xml

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:key="application_preferences">
    <PreferenceCategory>
        <PreferenceScreen
                android:key="url_settings"
                android:title="@string/url_settings"
                android:summary="@string/summary_url_settings">
        </PreferenceScreen>

        <PreferenceScreen
                android:key="currency_codes"
                android:title="@string/left_handed"
                android:summary="@string/summary_left_handed">
            <Preference
                    android:key="currency_exchanges"
                    android:layout="@layout/currencycodes"/>
        </PreferenceScreen>
        <EditTextPreference
                android:key="url_exchange_rate"
                android:title="@string/url_exchange_rate_settings"
                android:summary="@string/summary_url_exchange_rate"
                android:enabled = "false"/>
    </PreferenceCategory>
</PreferenceScreen>

What follows is the custom layout used. It contains a GridView.

currencycodes.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:id="@+id/activity_main"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:focusable="true"
        android:focusableInTouchMode="true"
        tools:context=".MainActivity">

    <GridView
            android:layout_width="328dp"
            android:layout_height="479dp"
            android:layout_marginTop="16dp"
            app:layout_constraintTop_toTopOf="parent" android:layout_marginStart="16dp"
            app:layout_constraintLeft_toLeftOf="parent" android:layout_marginEnd="16dp"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintBottom_toBottomOf="parent" android:layout_marginBottom="16dp"
            android:id="@+id/grdExchanges" android:scrollbars="horizontal|vertical"
            android:smoothScrollbar="true" tools:textAlignment="center"
            android:verticalScrollbarPosition="defaultPosition"/>
</android.support.constraint.ConstraintLayout>

Answer 1

Well first of all you need to understand how PreferenceScreen Works??

From [Android Documentation][1]:

When it appears inside another preference hierarchy, it is shown and serves as the gateway to another screen of preferences (either by showing another screen of preferences as a Dialog or via a startActivity(android.content.Intent) from the getIntent()). The children of this PreferenceScreen are NOT shown in the screen that this PreferenceScreen is shown in. Instead, a separate screen will be shown when this preference is clicked.

In Simple Words,

The preference framework handles showing these other screens from the preference hierarchy. This PreferenceScreen tag serves as a screen break (similar to page break in word processing).Like for other preference types, we assign a key here so it is able to save and restore its instance state.

In your case ,what actually happening is "application_preferences" will be used as the root of the hierarchy and given to a PreferenceActivity.The first screen will show preferences "Url_Setting" and "Currency Codes". The "Currency Codes" is the "second_preferencescreen" and when clicked will show another screen of preferences which is "Currency Exchange" (as it preferences as children of the "second_preferencescreen" tag i.e. Currency Codes).

So ,That why its not showing on first click....but on second click hope you got how preference Screen works...

If you still have any doubts...let me know... https://developer.android.com/reference/android/preference/PreferenceScreen.html