Java tutorial
package com.pemikir.youtubeplus; import android.app.Activity; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.os.Bundle; import android.os.Handler; import android.support.v4.app.ListFragment; import android.util.Log; import android.view.View; import android.widget.AbsListView; import android.widget.ListView; import android.widget.Toast; import java.net.URL; import java.util.Vector; /** * Copyright (C) Christian Schabesberger 2015 <chris.schabesberger@mailbox.org> * VideoItemListFragment.java is part of NewPipe. * <p/> * NewPipe is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * <p/> * NewPipe is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * <p/> * You should have received a copy of the GNU General Public License * along with NewPipe. If not, see <http://www.gnu.org/licenses/>. */ public class VideoItemListFragment extends ListFragment { private static final String TAG = VideoItemListFragment.class.toString(); /** * The serialization (saved instance state) Bundle key representing the * activated item position. Only used on tablets. */ private static final String STATE_ACTIVATED_POSITION = "activated_position"; Callbacks mCallbacks = null; private StreamingService streamingService = null; private VideoListAdapter videoListAdapter; private String query = ""; private int lastPage = 0; private Thread searchThread = null; private SearchRunnable searchRunnable = null; private Thread loadThumbsThread = null; private LoadThumbsRunnable loadThumbsRunnable = null; // used to track down if results posted by threads ar still valid private int currentRequestId = -1; /** * The current activated item position. Only used on tablets. */ private int mActivatedPosition = ListView.INVALID_POSITION; public void search(String query) { this.query = query; this.lastPage = 1; videoListAdapter.clearVideoList(); setListShown(false); startSearch(query, lastPage); getListView().smoothScrollToPosition(0); } public void nextPage() { lastPage++; Log.d(TAG, getString(R.string.searchPage) + Integer.toString(lastPage)); startSearch(query, lastPage); } private void startSearch(String query, int page) { currentRequestId++; terminateThreads(); searchRunnable = new SearchRunnable(streamingService.getSearchEngineClass(), query, page, currentRequestId); searchThread = new Thread(searchRunnable); searchThread.start(); } public void setStreamingService(StreamingService streamingService) { this.streamingService = streamingService; } public void updateListOnResult(SearchEngine.Result result, int requestId) { if (requestId == currentRequestId) { setListShown(true); if (result.resultList.isEmpty()) { Toast.makeText(getActivity(), result.errorMessage, Toast.LENGTH_LONG).show(); } else { if (!result.suggestion.isEmpty()) { Toast.makeText(getActivity(), getString(R.string.didYouMean) + result.suggestion + " ?", Toast.LENGTH_LONG).show(); } updateList(result.resultList); } } } private void updateList(Vector<VideoInfoItem> list) { try { videoListAdapter.addVideoList(list); terminateThreads(); loadThumbsRunnable = new LoadThumbsRunnable(videoListAdapter.getVideoList(), videoListAdapter.getDownloadedThumbnailList(), currentRequestId); loadThumbsThread = new Thread(loadThumbsRunnable); loadThumbsThread.start(); } catch (java.lang.IllegalStateException e) { Log.w(TAG, "Trying to set value while activity is not existing anymore."); } catch (Exception e) { e.printStackTrace(); } } public void terminateThreads() { if (loadThumbsRunnable != null && loadThumbsRunnable.isRunning()) { loadThumbsRunnable.terminate(); try { loadThumbsThread.join(); } catch (Exception e) { e.printStackTrace(); } } if (searchThread != null) { searchRunnable.terminate(); // No need to join, since we don't realy terminate the thread. We just demand // it to post its result runnable into the gui main loop. } } void displayList() { } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); } @Override public void onViewCreated(View view, Bundle savedInstanceState) { super.onViewCreated(view, savedInstanceState); videoListAdapter = new VideoListAdapter(getActivity(), this); setListAdapter(videoListAdapter); // Restore the previously serialized activated item position. if (savedInstanceState != null && savedInstanceState.containsKey(STATE_ACTIVATED_POSITION)) { setActivatedPosition(savedInstanceState.getInt(STATE_ACTIVATED_POSITION)); } getListView().setOnScrollListener(new AbsListView.OnScrollListener() { private static final float OVERSCROLL_THRESHOLD_IN_PIXELS = 100; long lastScrollDate = 0; private float downY; @Override public void onScrollStateChanged(AbsListView view, int scrollState) { } @Override public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) { ListView list = getListView(); if (list.getChildAt(0) != null && list.getLastVisiblePosition() == list.getAdapter().getCount() - 1 && list.getChildAt(list.getChildCount() - 1).getBottom() <= list.getHeight()) { long time = System.currentTimeMillis(); if ((time - lastScrollDate) > 200) { lastScrollDate = time; nextPage(); } } } }); } @Override public void onAttach(Activity activity) { super.onAttach(activity); // Activities containing this fragment must implement its callbacks. if (!(activity instanceof Callbacks)) { throw new IllegalStateException("Activity must implement fragment's callbacks."); } mCallbacks = (Callbacks) activity; } @Override public void onDetach() { super.onDetach(); } @Override public void onListItemClick(ListView listView, View view, int position, long id) { super.onListItemClick(listView, view, position, id); setActivatedPosition(position); mCallbacks.onItemSelected(Long.toString(id)); } @Override public void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); /* if (mActivatedPosition != ListView.INVALID_POSITION) { // Serialize and persist the activated item position. outState.putInt(STATE_ACTIVATED_POSITION, mActivatedPosition); } */ } /** * Turns on activate-on-click mode. When this mode is on, list items will be * given the 'activated' state when touched. */ public void setActivateOnItemClick(boolean activateOnItemClick) { // When setting CHOICE_MODE_SINGLE, ListView will automatically // give items the 'activated' state when touched. getListView().setChoiceMode(activateOnItemClick ? ListView.CHOICE_MODE_SINGLE : ListView.CHOICE_MODE_NONE); } private void setActivatedPosition(int position) { if (position == ListView.INVALID_POSITION) { getListView().setItemChecked(mActivatedPosition, false); } else { getListView().setItemChecked(position, true); } mActivatedPosition = position; } /** * A callback interface that all activities containing this fragment must * implement. This mechanism allows activities to be notified of item * selections. */ public interface Callbacks { /** * Callback for when an item has been selected. */ void onItemSelected(String id); } private class ResultRunnable implements Runnable { private SearchEngine.Result result; private int reuqestId; public ResultRunnable(SearchEngine.Result result, int requestId) { this.result = result; this.reuqestId = requestId; } @Override public void run() { updateListOnResult(result, reuqestId); } } private class SearchRunnable implements Runnable { Handler h = new Handler(); private Class engineClass = null; private String query; private int page; private volatile boolean run = true; private int requestId; public SearchRunnable(Class engineClass, String query, int page, int requestId) { this.engineClass = engineClass; this.query = query; this.page = page; this.requestId = requestId; } void terminate() { run = false; } @Override public void run() { SearchEngine engine = null; try { engine = (SearchEngine) engineClass.newInstance(); } catch (Exception e) { e.printStackTrace(); return; } try { SearchEngine.Result result = engine.search(query, page); if (run) { h.post(new ResultRunnable(result, requestId)); } } catch (Exception e) { e.printStackTrace(); h.post(new Runnable() { @Override public void run() { Toast.makeText(getActivity(), "Network Error", Toast.LENGTH_SHORT).show(); } }); } } } private class LoadThumbsRunnable implements Runnable { Handler h = new Handler(); private Vector<String> thumbnailUrlList = new Vector<>(); private Vector<Boolean> downloadedList; private volatile boolean run = true; private int requestId; public LoadThumbsRunnable(Vector<VideoInfoItem> videoList, Vector<Boolean> downloadedList, int requestId) { for (VideoInfoItem item : videoList) { thumbnailUrlList.add(item.thumbnail_url); } this.downloadedList = downloadedList; this.requestId = requestId; } public void terminate() { run = false; } public boolean isRunning() { return run; } @Override public void run() { for (int i = 0; i < thumbnailUrlList.size() && run; i++) { if (!downloadedList.get(i)) { Bitmap thumbnail = null; try { thumbnail = BitmapFactory .decodeStream(new URL(thumbnailUrlList.get(i)).openConnection().getInputStream()); h.post(new SetThumbnailRunnable(i, thumbnail, requestId)); } catch (Exception e) { e.printStackTrace(); } } } } } private class SetThumbnailRunnable implements Runnable { private int index; private Bitmap thumbnail; private int requestId; public SetThumbnailRunnable(int index, Bitmap thumbnail, int requestId) { this.index = index; this.thumbnail = thumbnail; this.requestId = requestId; } @Override public void run() { if (requestId == currentRequestId) { videoListAdapter.updateDownloadedThumbnailList(index, true); videoListAdapter.setThumbnail(index, thumbnail); } } } }