LeanbackSettingsFragmentCompat.java
/*
* Copyright 2018 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.leanback.preference;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentTransaction;
import androidx.preference.EditTextPreference;
import androidx.preference.ListPreference;
import androidx.preference.MultiSelectListPreference;
import androidx.preference.Preference;
import androidx.preference.PreferenceFragment;
import androidx.preference.PreferenceFragmentCompat;
import androidx.preference.PreferenceScreen;
/**
* This fragment provides a container for displaying a {@link LeanbackPreferenceFragmentCompat}
*
* <p>The following sample code shows a simple leanback preference fragment that is
* populated from a resource. The resource it loads is:</p>
*
* {@sample frameworks/support/samples/SupportPreferenceDemos/src/main/res/xml/preferences.xml preferences}
*
* <p>The sample implements
* {@link PreferenceFragmentCompat.OnPreferenceStartFragmentCallback#onPreferenceStartFragment(
* PreferenceFragmentCompat, Preference)},
* {@link PreferenceFragmentCompat.OnPreferenceStartScreenCallback#onPreferenceStartScreen(
* PreferenceFragmentCompat, PreferenceScreen)},
* and {@link #onPreferenceStartInitialScreen()}:</p>
*
* {@sample frameworks/support/samples/SupportPreferenceDemos/src/main/java/com/example/androidx/preference/LeanbackPreferences.java leanback_preferences}
*/
public abstract class LeanbackSettingsFragmentCompat extends Fragment
implements PreferenceFragmentCompat.OnPreferenceStartFragmentCallback,
PreferenceFragmentCompat.OnPreferenceStartScreenCallback,
PreferenceFragmentCompat.OnPreferenceDisplayDialogCallback {
private static final String PREFERENCE_FRAGMENT_TAG =
"androidx.leanback.preference.LeanbackSettingsFragment.PREFERENCE_FRAGMENT";
private final RootViewOnKeyListener mRootViewOnKeyListener = new RootViewOnKeyListener();
@Override
public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
final View v = inflater.inflate(R.layout.leanback_settings_fragment, container, false);
return v;
}
@Override
public void onViewCreated(@NonNull View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
if (savedInstanceState == null) {
onPreferenceStartInitialScreen();
}
}
@Override
public void onResume() {
super.onResume();
// Trap back button presses
final LeanbackSettingsRootView rootView = (LeanbackSettingsRootView) getView();
if (rootView != null) {
rootView.setOnBackKeyListener(mRootViewOnKeyListener);
}
}
@Override
public void onPause() {
super.onPause();
final LeanbackSettingsRootView rootView = (LeanbackSettingsRootView) getView();
if (rootView != null) {
rootView.setOnBackKeyListener(null);
}
}
@Override
public boolean onPreferenceDisplayDialog(@NonNull PreferenceFragmentCompat caller,
Preference pref) {
if (caller == null) {
throw new IllegalArgumentException("Cannot display dialog for preference " + pref
+ ", Caller must not be null!");
}
final Fragment f;
if (pref instanceof ListPreference) {
final ListPreference listPreference = (ListPreference) pref;
f = LeanbackListPreferenceDialogFragmentCompat.newInstanceSingle(
listPreference.getKey());
f.setTargetFragment(caller, 0);
startPreferenceFragment(f);
} else if (pref instanceof MultiSelectListPreference) {
MultiSelectListPreference listPreference = (MultiSelectListPreference) pref;
f = LeanbackListPreferenceDialogFragmentCompat.newInstanceMulti(
listPreference.getKey());
f.setTargetFragment(caller, 0);
startPreferenceFragment(f);
} else if (pref instanceof EditTextPreference) {
f = LeanbackEditTextPreferenceDialogFragmentCompat.newInstance(pref.getKey());
f.setTargetFragment(caller, 0);
startPreferenceFragment(f);
} else {
return false;
}
return true;
}
/**
* Called to instantiate the initial {@link PreferenceFragment}
* to be shown in this fragment. Implementations are expected to call
* {@link #startPreferenceFragment(Fragment)}.
*/
public abstract void onPreferenceStartInitialScreen();
/**
* Displays a preference fragment to the user. This method can also be used to display
* list-style fragments on top of the stack of preference fragments.
*
* @param fragment Fragment instance to be added.
*/
public void startPreferenceFragment(@NonNull Fragment fragment) {
final FragmentTransaction transaction = getChildFragmentManager().beginTransaction();
final Fragment prevFragment =
getChildFragmentManager().findFragmentByTag(PREFERENCE_FRAGMENT_TAG);
if (prevFragment != null) {
transaction
.addToBackStack(null)
.replace(R.id.settings_preference_fragment_container, fragment,
PREFERENCE_FRAGMENT_TAG);
} else {
transaction
.add(R.id.settings_preference_fragment_container, fragment,
PREFERENCE_FRAGMENT_TAG);
}
transaction.commit();
}
/**
* Displays a fragment to the user, temporarily replacing the contents of this fragment.
*
* @param fragment Fragment instance to be added.
*/
public void startImmersiveFragment(@NonNull Fragment fragment) {
final FragmentTransaction transaction = getChildFragmentManager().beginTransaction();
final Fragment preferenceFragment =
getChildFragmentManager().findFragmentByTag(PREFERENCE_FRAGMENT_TAG);
if (preferenceFragment != null && !preferenceFragment.isHidden()) {
transaction.remove(preferenceFragment);
}
transaction
.add(R.id.settings_dialog_container, fragment)
.addToBackStack(null)
.commit();
}
private class RootViewOnKeyListener implements View.OnKeyListener {
RootViewOnKeyListener() {
}
@Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
return getChildFragmentManager().popBackStackImmediate();
} else {
return false;
}
}
}
}