我有一個帶有導航菜單的導航菜單。當點擊每個導航菜單時,打開特定的片段。例如,當我點擊Words導航菜單時,單詞項目上會顯示recyclerView
項目。我從脫機和外部SQLite數據庫獲取數據,並在recyclerView
項目上顯示。現在我想在另一個線程中獲取數據,而不是在主線程中,因爲我想要提高加載速度數據和應用性能。但我不知道該怎麼做。請用代碼幫助我。我在網上閱讀了相同的主題,但我現在仍然有我的問題。使用AsyncTask從sqlite數據庫加載數據並在recyclerview項目中顯示
這是我AllWordsFragment
public class AllWordsFragment extends Fragment {
private List<WordsList> wordsLists = new ArrayList<>();
private Cursor cursor;
ProgressBar progressBar;
RecyclerView recyclerView;
AllWordsAdapter allWordsAdapter;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater,
@Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.all_words_fragment, container, false);
progressBar = view.findViewById(R.id.progressBar);
progressBar.setMax(600);
allWordsAdapter = new AllWordsAdapter(getActivity(), wordsLists);
allWordsAdapter.notifyDataSetChanged();
recyclerView = view.findViewById(R.id.recyclerViewAllWords);
RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getActivity());
recyclerView.setLayoutManager(layoutManager);
recyclerView.setItemAnimator(new DefaultItemAnimator());
recyclerView.setHasFixedSize(true);
recyclerView.setAdapter(allWordsAdapter);
loadingWords();
return view;
}
private void loadingWords() {
WordDatabase wordDatabase = new WordDatabase(getActivity());
try {
wordDatabase.createDatabase();
wordDatabase.openDatabase();
} catch (SQLiteException e) {
e.printStackTrace();
}
try {
cursor = wordDatabase.QueryData("SELECT Word, Definition, Example, WordList, ImageWord FROM Words");
if (cursor != null && cursor.moveToFirst()) {
do {
WordsList wordList = new WordsList();
wordList.setWordTitle(cursor.getString(0));
wordList.setDefinition(cursor.getString(1));
wordList.setExample(cursor.getString(2));
wordList.setVocubList(cursor.getString(3));
wordList.setImageWord(cursor.getString(4));
wordsLists.add(wordList);
} while (cursor.moveToNext());
wordDatabase.close();
}
} catch (SQLiteException w) {
w.printStackTrace();
} finally {
if (cursor != null) {
cursor.close();
}
}
}
,這是我AllWordsAdapter
公共類AllWordsAdapter擴展RecyclerView.Adapter {
private int lastPosition = -1;
protected Context context;
private List<WordsList> wordsListList = new ArrayList<>();
public AllWordsAdapter(Context context, List<WordsList> wordsListList) {
this.context = context;
this.wordsListList = wordsListList;
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(context).inflate(R.layout.all_words_item, parent, false);
return new ViewHolder(view);
}
@Override
public void onBindViewHolder(final ViewHolder holder, int position) {
WordsList wordsList = wordsListList.get(position);
holder.wordTitle.setText(wordsList.getWordTitle());
holder.definitionWord.setText(Html.fromHtml(wordsList.getDefinition()));
holder.exampleWord.setText(Html.fromHtml(wordsList.getExample()));
holder.labelWordList.setLabelText(wordsList.getVocubList());
//get image from assets with Glide.
String pathImage = wordsList.getImageWord();
String assetsPath = "file:///android_asset/";
Glide.with(context)
.asBitmap()
.load(Uri.parse(assetsPath + "" + pathImage))
.into(holder.wordImage);
Log.d("path", assetsPath + "" + pathImage);
Typeface headerFont = Typeface.createFromAsset(context.getAssets(), "fonts/Roboto-Bold.ttf");
holder.wordTitle.setTypeface(headerFont);
Typeface customFont = Typeface.createFromAsset(context.getAssets(), "fonts/Roboto-Italic.ttf");
holder.exampleWord.setTypeface(customFont);
holder.definitionWord.setTypeface(customFont);
//cal animation function
setAnimation(holder.itemView, position);
holder.relativeLayout.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(context, AllWordsDetails.class);
intent.putExtra("word", holder.wordTitle.getText().toString());
context.startActivity(intent);
}
});
}
@Override
public int getItemCount() {
return wordsListList.size();
}
public class ViewHolder extends RecyclerView.ViewHolder {
private CircleImageView wordImage;
private LabelTextView labelWordList;
private TextView wordTitle, definitionWord, exampleWord;
private RelativeLayout relativeLayout;
public ViewHolder(View itemView) {
super(itemView);
wordTitle = itemView.findViewById(R.id.allWordTitle);
wordImage = itemView.findViewById(R.id.circleHeaderImage);
exampleWord = itemView.findViewById(R.id.exampleAllWord);
definitionWord = itemView.findViewById(R.id.definitionAllWord);
labelWordList = itemView.findViewById(R.id.labelWordList);
relativeLayout = itemView.findViewById(R.id.relativeAllWords);
}
}
private void setAnimation(View viewToAnimation, int position) {
// If the bound view wasn't previously displayed on screen, it's animated
if (position > lastPosition) {
ScaleAnimation scaleAnimation = new ScaleAnimation(0.0f, 1.0f, 0.0f, 1.0f,
Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
scaleAnimation.setDuration(new Random().nextInt(501));//to make duration random number between [0,501)
viewToAnimation.startAnimation(scaleAnimation);
lastPosition = position;
}
}
}
我知道必須使用AsyncTask並在後臺做到這一點,但我不知道這是怎麼回事?請幫我一個代碼。 謝謝。
謝謝親愛的@Yazan。 :)工作。萬分感謝。太簡單 :)。只是我不記得在onPostExecute中通知我的適配器。 –