Java tutorial
/* This file is auto-generated from BaseRowFragment.java. DO NOT MODIFY. */ /* * Copyright (C) 2014 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 android.support.v17.leanback.app; import android.support.v4.app.Fragment; import android.os.Bundle; import android.support.v17.leanback.widget.ItemBridgeAdapter; import android.support.v17.leanback.widget.ListRow; import android.support.v17.leanback.widget.ObjectAdapter; import android.support.v17.leanback.widget.OnChildViewHolderSelectedListener; import android.support.v17.leanback.widget.PresenterSelector; import android.support.v17.leanback.widget.Row; import android.support.v17.leanback.widget.VerticalGridView; import android.support.v7.widget.RecyclerView; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; /** * An internal base class for a fragment containing a list of rows. */ abstract class BaseRowSupportFragment extends Fragment { private static final String CURRENT_SELECTED_POSITION = "currentSelectedPosition"; private ObjectAdapter mAdapter; private VerticalGridView mVerticalGridView; private PresenterSelector mPresenterSelector; private ItemBridgeAdapter mBridgeAdapter; private int mSelectedPosition = -1; private boolean mPendingTransitionPrepare; private LateSelectionObserver mLateSelectionObserver = new LateSelectionObserver(); abstract int getLayoutResourceId(); private final OnChildViewHolderSelectedListener mRowSelectedListener = new OnChildViewHolderSelectedListener() { @Override public void onChildViewHolderSelected(RecyclerView parent, RecyclerView.ViewHolder view, int position, int subposition) { mSelectedPosition = position; onRowSelected(parent, view, position, subposition); } }; void onRowSelected(RecyclerView parent, RecyclerView.ViewHolder view, int position, int subposition) { } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View view = inflater.inflate(getLayoutResourceId(), container, false); mVerticalGridView = findGridViewFromRoot(view); if (mPendingTransitionPrepare) { mPendingTransitionPrepare = false; onTransitionPrepare(); } return view; } VerticalGridView findGridViewFromRoot(View view) { return (VerticalGridView) view; } @Override public void onViewCreated(View view, Bundle savedInstanceState) { if (savedInstanceState != null) { mSelectedPosition = savedInstanceState.getInt(CURRENT_SELECTED_POSITION, -1); } if (mBridgeAdapter != null) { setAdapterAndSelection(); } mVerticalGridView.setOnChildViewHolderSelectedListener(mRowSelectedListener); } /** * This class waits for the adapter to be updated before setting the selected * row. */ private class LateSelectionObserver extends RecyclerView.AdapterDataObserver { boolean mIsLateSelection = false; public void onChanged() { performLateSelection(); } public void onItemRangeInserted(int positionStart, int itemCount) { performLateSelection(); } void startLateSelection() { mIsLateSelection = true; mBridgeAdapter.registerAdapterDataObserver(this); } void performLateSelection() { clear(); if (mVerticalGridView != null) { mVerticalGridView.setSelectedPosition(mSelectedPosition); } } void clear() { if (mIsLateSelection) { mIsLateSelection = false; mBridgeAdapter.unregisterAdapterDataObserver(this); } } } void setAdapterAndSelection() { mVerticalGridView.setAdapter(mBridgeAdapter); // We don't set the selected position unless we've data in the adapter. boolean lateSelection = mBridgeAdapter.getItemCount() == 0 && mSelectedPosition >= 0; if (lateSelection) { mLateSelectionObserver.startLateSelection(); } else if (mSelectedPosition >= 0) { mVerticalGridView.setSelectedPosition(mSelectedPosition); } } @Override public void onDestroyView() { super.onDestroyView(); mLateSelectionObserver.clear(); mVerticalGridView = null; } @Override public void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); outState.putInt(CURRENT_SELECTED_POSITION, mSelectedPosition); } /** * Set the presenter selector used to create and bind views. */ public final void setPresenterSelector(PresenterSelector presenterSelector) { mPresenterSelector = presenterSelector; updateAdapter(); } /** * Get the presenter selector used to create and bind views. */ public final PresenterSelector getPresenterSelector() { return mPresenterSelector; } /** * Sets the adapter for the fragment. */ public final void setAdapter(ObjectAdapter rowsAdapter) { mAdapter = rowsAdapter; updateAdapter(); } /** * Returns the list of rows. */ public final ObjectAdapter getAdapter() { return mAdapter; } /** * Returns the bridge adapter. */ final ItemBridgeAdapter getBridgeAdapter() { return mBridgeAdapter; } /** * Sets the selected row position with smooth animation. */ public void setSelectedPosition(int position) { setSelectedPosition(position, true); } /** * Gets position of currently selected row. * @return Position of currently selected row. */ public int getSelectedPosition() { return mSelectedPosition; } /** * Sets the selected row position. */ public void setSelectedPosition(int position, boolean smooth) { if (mSelectedPosition == position) { return; } mSelectedPosition = position; if (mVerticalGridView != null && mVerticalGridView.getAdapter() != null) { if (mLateSelectionObserver.mIsLateSelection) { return; } if (smooth) { mVerticalGridView.setSelectedPositionSmooth(position); } else { mVerticalGridView.setSelectedPosition(position); } } } final VerticalGridView getVerticalGridView() { return mVerticalGridView; } void updateAdapter() { if (mBridgeAdapter != null) { // detach observer from ObjectAdapter mLateSelectionObserver.clear(); mBridgeAdapter.clear(); mBridgeAdapter = null; } if (mAdapter != null) { // If presenter selector is null, adapter ps will be used mBridgeAdapter = new ItemBridgeAdapter(mAdapter, mPresenterSelector); } if (mVerticalGridView != null) { setAdapterAndSelection(); } } Object getItem(Row row, int position) { if (row instanceof ListRow) { return ((ListRow) row).getAdapter().get(position); } else { return null; } } public boolean onTransitionPrepare() { if (mVerticalGridView != null) { mVerticalGridView.setAnimateChildLayout(false); mVerticalGridView.setScrollEnabled(false); return true; } mPendingTransitionPrepare = true; return false; } public void onTransitionStart() { if (mVerticalGridView != null) { mVerticalGridView.setPruneChild(false); mVerticalGridView.setLayoutFrozen(true); mVerticalGridView.setFocusSearchDisabled(true); } } public void onTransitionEnd() { // be careful that fragment might be destroyed before header transition ends. if (mVerticalGridView != null) { mVerticalGridView.setLayoutFrozen(false); mVerticalGridView.setAnimateChildLayout(true); mVerticalGridView.setPruneChild(true); mVerticalGridView.setFocusSearchDisabled(false); mVerticalGridView.setScrollEnabled(true); } } public void setAlignment(int windowAlignOffsetTop) { if (mVerticalGridView != null) { // align the top edge of item mVerticalGridView.setItemAlignmentOffset(0); mVerticalGridView.setItemAlignmentOffsetPercent(VerticalGridView.ITEM_ALIGN_OFFSET_PERCENT_DISABLED); // align to a fixed position from top mVerticalGridView.setWindowAlignmentOffset(windowAlignOffsetTop); mVerticalGridView .setWindowAlignmentOffsetPercent(VerticalGridView.WINDOW_ALIGN_OFFSET_PERCENT_DISABLED); mVerticalGridView.setWindowAlignment(VerticalGridView.WINDOW_ALIGN_NO_EDGE); } } }