این وبسایت یک نسخه آزمایشی از سایت developer android می‌باشد که در حال ترجمه می‌باشد.
برای پیوستن به تیم ترجمه و خواندن مستندات اینجا کلیک کنید.
AdapterTransition / src / com.example.android.adaptertransition /

AdapterTransitionFragment.java

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/*
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 * Copyright 2014 The Android Open Source Project
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 *
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 * Licensed under the Apache License, Version 2.0 (the "License");
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 * you may not use this file except in compliance with the License.
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 * You may obtain a copy of the License at
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 *
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 *     http://www.apache.org/licenses/LICENSE-2.0
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 *
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 * Unless required by applicable law or agreed to in writing, software
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 * distributed under the License is distributed on an "AS IS" BASIS,
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 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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 * See the License for the specific language governing permissions and
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 * limitations under the License.
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 */
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package com.example.android.adaptertransition;
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import android.os.Bundle;
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import android.support.v4.app.ActivityCompat;
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import android.support.v4.app.Fragment;
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import android.transition.AutoTransition;
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import android.transition.Scene;
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import android.transition.Transition;
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import android.transition.TransitionManager;
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import android.view.LayoutInflater;
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import android.view.Menu;
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import android.view.MenuInflater;
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import android.view.MenuItem;
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import android.view.View;
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import android.view.ViewGroup;
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import android.widget.AbsListView;
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import android.widget.FrameLayout;
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import android.widget.GridView;
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import android.widget.ListView;
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import android.widget.Toast;
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/**
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 * Main screen for AdapterTransition sample.
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 */
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public class AdapterTransitionFragment extends Fragment implements Transition.TransitionListener {
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    /**
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     * Since the transition framework requires all relevant views in a view hierarchy to be marked
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     * with IDs, we use this ID to mark the root view.
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     */
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    private static final int ROOT_ID = 1;
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    /**
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     * A tag for saving state whether the mAbsListView is ListView or GridView.
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     */
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    private static final String STATE_IS_LISTVIEW = "is_listview";
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    /**
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     * This is where we place our AdapterView (ListView / GridView).
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     */
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    private FrameLayout mContent;
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    /**
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     * This is where we carry out the transition.
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     */
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    private FrameLayout mCover;
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    /**
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     * This list shows our contents. It can be ListView or GridView, and we toggle between them
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     * using the transition framework.
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     */
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    private AbsListView mAbsListView;
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    /**
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     * This is our contents.
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     */
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    private MeatAdapter mAdapter;
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    public static AdapterTransitionFragment newInstance() {
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        return new AdapterTransitionFragment();
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    }
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    public AdapterTransitionFragment() {
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    }
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    @Override
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    public void onCreate(Bundle savedInstanceState) {
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        super.onCreate(savedInstanceState);
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        setHasOptionsMenu(true);
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    }
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    @Override
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    public View onCreateView(LayoutInflater inflater, ViewGroup container,
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                             Bundle savedInstanceState) {
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        // If savedInstanceState is available, we restore the state whether the list is a ListView
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        // or a GridView.
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        boolean isListView;
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        if (null == savedInstanceState) {
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            isListView = true;
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        } else {
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            isListView = savedInstanceState.getBoolean(STATE_IS_LISTVIEW, true);
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        }
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        inflateAbsList(inflater, container, isListView);
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        return inflater.inflate(R.layout.fragment_adapter_transition, container, false);
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    }
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    @Override
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    public void onSaveInstanceState(Bundle outState) {
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        super.onSaveInstanceState(outState);
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        outState.putBoolean(STATE_IS_LISTVIEW, mAbsListView instanceof ListView);
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    }
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    @Override
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    public void onViewCreated(View view, Bundle savedInstanceState) {
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        // Retaining references for FrameLayouts that we use later.
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        mContent = (FrameLayout) view.findViewById(R.id.content);
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        mCover = (FrameLayout) view.findViewById(R.id.cover);
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        // We are attaching the list to the screen here.
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        mContent.addView(mAbsListView);
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    }
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    @Override
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    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
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        inflater.inflate(R.menu.fragment_adapter_transition, menu);
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    }
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    @Override
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    public void onPrepareOptionsMenu(Menu menu) {
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        // We change the look of the icon every time the user toggles between list and grid.
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        MenuItem item = menu.findItem(R.id.action_toggle);
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        if (null != item) {
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            if (mAbsListView instanceof ListView) {
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                item.setIcon(R.drawable.ic_action_grid);
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                item.setTitle(R.string.show_as_grid);
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            } else {
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                item.setIcon(R.drawable.ic_action_list);
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                item.setTitle(R.string.show_as_list);
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            }
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        }
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    }
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    @Override
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    public boolean onOptionsItemSelected(MenuItem item) {
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        switch (item.getItemId()) {
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            case R.id.action_toggle: {
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                toggle();
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                return true;
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            }
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        }
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        return false;
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    }
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    @Override
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    public void onTransitionStart(Transition transition) {
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    }
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    @Override
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    public void onTransitionEnd(Transition transition) {
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        // When the transition ends, we remove all the views from the overlay and hide it.
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        mCover.removeAllViews();
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        mCover.setVisibility(View.INVISIBLE);
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    }
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    @Override
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    public void onTransitionCancel(Transition transition) {
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    }
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    @Override
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    public void onTransitionPause(Transition transition) {
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    }
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    @Override
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    public void onTransitionResume(Transition transition) {
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    }
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    /**
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     * Inflate a ListView or a GridView with a corresponding ListAdapter.
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     *
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     * @param inflater The LayoutInflater.
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     * @param container The ViewGroup that contains this AbsListView. The AbsListView won't be
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     *                  attached to it.
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     * @param inflateListView Pass true to inflate a ListView, or false to inflate a GridView.
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     */
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    private void inflateAbsList(LayoutInflater inflater, ViewGroup container,
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                                boolean inflateListView) {
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        if (inflateListView) {
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            mAbsListView = (AbsListView) inflater.inflate(R.layout.fragment_meat_list,
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                    container, false);
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            mAdapter = new MeatAdapter(inflater, R.layout.item_meat_list);
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        } else {
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            mAbsListView = (AbsListView) inflater.inflate(R.layout.fragment_meat_grid,
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                    container, false);
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            mAdapter = new MeatAdapter(inflater, R.layout.item_meat_grid);
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        }
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        mAbsListView.setAdapter(mAdapter);
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        mAbsListView.setOnItemClickListener(mAdapter);
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    }
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    /**
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     * Toggle the UI between ListView and GridView.
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     */
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    private void toggle() {
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        // We use mCover as the overlay on which we carry out the transition.
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        mCover.setVisibility(View.VISIBLE);
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        // This FrameLayout holds all the visible views in the current list or grid. We use this as
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        // the starting Scene of the Transition later.
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        FrameLayout before = copyVisibleViews();
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        FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(
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                FrameLayout.LayoutParams.MATCH_PARENT, FrameLayout.LayoutParams.MATCH_PARENT);
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        mCover.addView(before, params);
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        // Swap the actual list.
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        swapAbsListView();
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        // We also swap the icon for the toggle button.
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        ActivityCompat.invalidateOptionsMenu(getActivity());
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        // It is now ready to start the transition.
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        mAbsListView.post(new Runnable() {
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            @Override
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            public void run() {
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                Scene scene = new Scene(mCover, copyVisibleViews());
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                Transition transition = new AutoTransition();
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                transition.addListener(AdapterTransitionFragment.this);
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                TransitionManager.go(scene, transition);
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            }
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        });
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    }
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    /**
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     * Swap ListView with GridView, or GridView with ListView.
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     */
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    private void swapAbsListView() {
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        // We save the current scrolling position before removing the current list.
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        int first = mAbsListView.getFirstVisiblePosition();
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        // If the current list is a GridView, we replace it with a ListView. If it is a ListView,
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        // a GridView.
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        LayoutInflater inflater = LayoutInflater.from(getActivity());
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        inflateAbsList(inflater, (ViewGroup) mAbsListView.getParent(),
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                mAbsListView instanceof GridView);
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        mAbsListView.setAdapter(mAdapter);
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        // We restore the scrolling position here.
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        mAbsListView.setSelection(first);
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        // The new list is ready, and we replace the existing one with it.
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        mContent.removeAllViews();
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        mContent.addView(mAbsListView);
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    }
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    /**
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     * Copy all the visible views in the mAbsListView into a new FrameLayout and return it.
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     *
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     * @return a FrameLayout with all the visible views inside.
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     */
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    private FrameLayout copyVisibleViews() {
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        // This is the FrameLayout we return afterwards.
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        FrameLayout layout = new FrameLayout(getActivity());
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        // The transition framework requires to set ID for all views to be animated.
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        layout.setId(ROOT_ID);
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        // We only copy visible views.
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        int first = mAbsListView.getFirstVisiblePosition();
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        int index = 0;
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        while (true) {
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            // This is one of the views that we copy. Note that the argument for getChildAt is a
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            // zero-oriented index, and it doesn't usually match with its position in the list.
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            View source = mAbsListView.getChildAt(index);
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            if (null == source) {
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                break;
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            }
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            // This is the copy of the original view.
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            View destination = mAdapter.getView(first + index, null, layout);
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            assert destination != null;
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            destination.setId(ROOT_ID + first + index);
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            FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(
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                    source.getWidth(), source.getHeight());
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            params.leftMargin = (int) source.getX();
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            params.topMargin = (int) source.getY();