Java tutorial
/* * Copyright (c) 2015 Ha Duy Trung * * 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 io.github.hidroh.materialistic; import android.content.Context; import android.graphics.Rect; import android.os.Bundle; import android.support.annotation.Nullable; import android.support.v4.app.DialogFragment; import android.support.v4.app.Fragment; import android.support.v7.widget.RecyclerView; import android.view.Menu; import android.view.MenuInflater; import android.view.MenuItem; import android.view.View; import javax.inject.Inject; import io.github.hidroh.materialistic.widget.ListRecyclerViewAdapter; import io.github.hidroh.materialistic.widget.SnappyLinearLayoutManager; abstract class BaseListFragment extends BaseFragment implements Scrollable { private static final String STATE_ADAPTER = "state:adapter"; @Inject CustomTabsDelegate mCustomTabsDelegate; private KeyDelegate.RecyclerViewHelper mScrollableHelper; protected RecyclerView mRecyclerView; private final Preferences.Observable mPreferenceObservable = new Preferences.Observable(); @Override public void onAttach(Context context) { super.onAttach(context); mPreferenceObservable.subscribe(context, this::onPreferenceChanged, R.string.pref_font, R.string.pref_text_size, R.string.pref_list_item_view); } @Override public void onCreate(@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); setHasOptionsMenu(true); if (savedInstanceState == null) { getAdapter().setCardViewEnabled(Preferences.isListItemCardView(getActivity())); } else { getAdapter().restoreState(savedInstanceState.getBundle(STATE_ADAPTER)); } } @Override public void onViewCreated(View view, @Nullable Bundle savedInstanceState) { super.onViewCreated(view, savedInstanceState); mRecyclerView.setLayoutManager(new SnappyLinearLayoutManager(getActivity(), false)); final int verticalMargin = getResources().getDimensionPixelSize(R.dimen.cardview_vertical_margin); final int horizontalMargin = getResources().getDimensionPixelSize(R.dimen.cardview_horizontal_margin); final int divider = getResources().getDimensionPixelSize(R.dimen.divider); mRecyclerView.addItemDecoration(new RecyclerView.ItemDecoration() { @Override public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) { if (getAdapter().isCardViewEnabled()) { outRect.set(horizontalMargin, verticalMargin, horizontalMargin, 0); } else { outRect.set(0, 0, 0, divider); } } }); } @Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); getAdapter().setCustomTabsDelegate(mCustomTabsDelegate); mRecyclerView.setAdapter(getAdapter()); mScrollableHelper = new KeyDelegate.RecyclerViewHelper(mRecyclerView, KeyDelegate.RecyclerViewHelper.SCROLL_PAGE); } @Override protected void createOptionsMenu(Menu menu, MenuInflater inflater) { inflater.inflate(R.menu.menu_list, menu); } @Override public boolean onOptionsItemSelected(MenuItem item) { if (item.getItemId() == R.id.menu_list) { showPreferences(); return true; } return super.onOptionsItemSelected(item); } private void showPreferences() { Bundle args = new Bundle(); args.putInt(PopupSettingsFragment.EXTRA_TITLE, R.string.list_display_options); args.putInt(PopupSettingsFragment.EXTRA_SUMMARY, R.string.pull_up_hint); args.putIntArray(PopupSettingsFragment.EXTRA_XML_PREFERENCES, new int[] { R.xml.preferences_font, R.xml.preferences_list }); ((DialogFragment) Fragment.instantiate(getActivity(), PopupSettingsFragment.class.getName(), args)) .show(getFragmentManager(), PopupSettingsFragment.class.getName()); } @Override public void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); outState.putBundle(STATE_ADAPTER, getAdapter().saveState()); } @Override public void onDetach() { super.onDetach(); mPreferenceObservable.unsubscribe(getActivity()); mRecyclerView.setAdapter(null); // force adapter detach } @Override public void scrollToTop() { mScrollableHelper.scrollToTop(); } @Override public boolean scrollToNext() { return mScrollableHelper.scrollToNext(); } @Override public boolean scrollToPrevious() { return mScrollableHelper.scrollToPrevious(); } private void onPreferenceChanged(int key, boolean contextChanged) { if (contextChanged) { mRecyclerView.setAdapter(getAdapter()); } else if (key == R.string.pref_list_item_view) { getAdapter().setCardViewEnabled(Preferences.isListItemCardView(getActivity())); } } protected abstract ListRecyclerViewAdapter getAdapter(); }