我有带导航菜单的导航栏。当点击每个项目导航抽屉时，加载了一个片段。在每个片段中，我从外部SQLite数据库加载数据，并使用Recyclerview显示。现在我想要点击它时添加收藏夹按钮，添加到收藏项目和背景收藏夹按钮的项目必须更改为喜欢。或者，当点击收藏项目时，项目UnFavorited和背景更改为UnLiked按钮。我在表格中创建了“收藏”列，并将每个原始数据设置为0 =文本，因为当首次加载应用时，没有任何项目不是最喜欢的。现在我不知道怎么做这个功能。请帮帮我。
这是我的 WorldCOuntryDabase
public class WorldCountryDatabase extends SQLiteOpenHelper {
private static final String TAG = "databaseHelper";
private static final String DB_NAME = "worldCountries.db";
private static final int DB_VERSION = 1;
private static final String TABLE_NAME = "country";
private static String DB_PATH = "";
private Context mContext;
private SQLiteDatabase database;
public WorldCountryDatabase(Context context) {
super(context, DB_NAME, null, DB_VERSION);
DB_PATH = context.getDatabasePath(DB_NAME).getPath();
File file = new File(DB_PATH + "worldCountries.db");
if (file.exists())
openDataBase();
this.mContext = context;
}
public void createDatabase() {
boolean dbExist = checkDatabase();
if (dbExist) {
Log.d("MIN1", "Database already Exist");
} else {
this.getReadableDatabase();
}
try {
copyDataBase();
} catch (IOException e) {
e.printStackTrace();
Log.i("MIN2", e.getMessage());
}
}
private boolean checkDatabase() {
SQLiteDatabase checkDB = null;
try {
String myPath = DB_PATH + DB_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE);
} catch (SQLiteException e) {
e.printStackTrace();
Log.d("MIN3", e.getMessage());
}
if (checkDB != null) {
checkDB.close();
}
return checkDB != null;
}
public synchronized void close() {
if (database != null) {
database.close();
SQLiteDatabase.releaseMemory();
}
super.close();
}
private void copyDataBase() throws IOException {
try {
InputStream in = mContext.getAssets().open(DB_NAME);
String outFileName = DB_PATH + DB_NAME;
OutputStream out = new FileOutputStream(outFileName);
byte[] buffer = new byte[1024];
int length;
while ((length = in.read(buffer)) > 0) {
out.write(buffer, 0, length);
}
out.flush();
out.close();
in.close();
Log.d("MIN4", "Database copy");
} catch (SQLiteException e) {
Log.d("MIN5", e.getMessage());
}
}
public Cursor QueryData(String query) {
return database.rawQuery(query, null);
}
@Override
public void onCreate(SQLiteDatabase db) {
Log.d("MIN6", "onCreate");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.v("LOG_TAG", "Upgrading Database from version" + oldVersion + "To" + newVersion +
"Which will destroy all oldest data");
if (newVersion > oldVersion) {
try {
copyDataBase();
} catch (IOException e) {
e.printStackTrace();
}
}
}
public void openDataBase() {
String myPath = DB_PATH + DB_NAME;
database = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE);
Log.d("MIN7", "Opened database");
}
// CRUD Table
public List<Questions> getAllQuestions() {
List<Questions> questionsList = new ArrayList<>();
SQLiteDatabase db = this.getWritableDatabase();
Cursor c;
try {
c = db.rawQuery("SELECT * FROM country ORDER BY Random()", null);
if (c == null) return null;
c.moveToFirst();
do {
int Id = c.getInt(c.getColumnIndex("id"));
String Image = c.getString(c.getColumnIndex("Image"));
String AnswerA = c.getString(c.getColumnIndex("AnswerA"));
String AnswerB = c.getString(c.getColumnIndex("AnswerB"));
String AnswerC = c.getString(c.getColumnIndex("AnswerC"));
String AnswerD = c.getString(c.getColumnIndex("AnswerD"));
String CorrectAnswer = c.getString(c.getColumnIndex("CorrectAnswer"));
Questions question = new Questions(Id, Image, AnswerA, AnswerB, AnswerC, AnswerD, CorrectAnswer);
questionsList.add(question);
} while (c.moveToNext());
c.close();
} catch (Exception e) {
e.printStackTrace();
}
database.close();
return questionsList;
}
// Insert Score to Ranking table.
public void insertScore(double score) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues content = new ContentValues();
content.put("Score", score);
db.insert("Ranking", null, content);
}
// Get score and sort Ranking.
public List<Ranking> getRanking() {
List<Ranking> rankingList = new ArrayList<>();
SQLiteDatabase db = this.getReadableDatabase();
Cursor c;
try {
c = db.rawQuery("SELECT * FROM Ranking ORDER BY Score DESC;", null);
if (c == null) return null;
c.moveToFirst();
do {
int Id = c.getInt(c.getColumnIndex("Id"));
int Score = c.getInt(c.getColumnIndex("Score"));
Ranking ranking = new Ranking(Id, Score);
rankingList.add(ranking);
} while (c.moveToNext());
c.close();
} catch (Exception e) {
e.printStackTrace();
}
db.close();
return rankingList;
}
//Update version 2.0
public int getPlayCount(int level) {
int result = 0;
SQLiteDatabase db = this.getReadableDatabase();
Cursor c;
try {
c = db.rawQuery("SELECT PlayCount FROM UserPlayCount WHERE Level=" + level + ";", null);
if (c == null) return 0;
c.moveToNext();
do {
result = c.getInt(c.getColumnIndex("PlayCount"));
} while (c.moveToNext());
c.close();
} catch (Exception ex) {
ex.printStackTrace();
}
return result;
}
public void updatePlayCount(int level, int PlayCount) {
String query = String.format("UPDATE UserPlayCount Set PlayCount = %d WHERE Level = %d", PlayCount, level);
database.execSQL(query);
}
这是我的 ContentAdapter
public class ContentAdapter extends RecyclerView.Adapter<ContentAdapter.ViewHolder> {
public Context context;
private boolean isFavorite;
WorldCountryDatabase worldCountryDatabase;
private List<AsiaCountry> item = Collections.emptyList();
private int mLastPosition = -1;
private Listener listener;
public ContentAdapter(Context context, List<AsiaCountry> item) {
this.context = context;
this.item = item;
}
public void setListener(Listener listener) {
this.listener = listener;
}
@Override
public ContentAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, final int viewType) {
//Defain the view for take layout
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item,
parent, false);
Log.d("Adapter", "Loaded");
return new ViewHolder(view);
}
@Override
public void onBindViewHolder(final ViewHolder holder, final int position) {
final AsiaCountry asia = item.get(position);
isFavorite = true;
holder.titleNameCountry.setText(asia.getName());
Log.d("TAG", asia.getName());
Glide.with(context).load(asia.getFlag(context)).into(holder.titleImageCountry);
holder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (listener != null) {
listener.onClick(position);
String nameCountry = holder.titleNameCountry.getText().toString();
Intent intent = new Intent(context, DetailsCountry.class);
intent.putExtra("name", nameCountry);
Log.d("CONT", nameCountry);
context.startActivity(intent);
}
}
});
if (position > mLastPosition) {
AnimatorSet animatorSet = new AnimatorSet();
animatorSet.playTogether(
ObjectAnimator.ofFloat(holder.itemView, "translationY",
holder.itemView.getMeasuredHeight() * 2, 0));
ObjectAnimator.ofFloat(holder.itemView, "alpha", 0, 1);
ObjectAnimator.ofFloat(holder.itemView, "scaleX", 0.5f, 1);
ObjectAnimator.ofFloat(holder.itemView, "scaleY", 0.5f, 1);
animatorSet.setInterpolator(new DecelerateInterpolator());
animatorSet.start();
mLastPosition = position;
} else {
ViewHolder.clear(holder.itemView);
}
}
private void updateUnFavoriteCountry() {
AsiaCountry asiaCountry;
int position = item.size();
asiaCountry = item.get(position);
String nameCountry = asiaCountry.getName();
worldCountryDatabase.QueryData("UPDATE country SET FavoriteCountry = 1 WHERE name =' " + nameCountry);
worldCountryDatabase.close();
}
private void updateFavoriteCountry() {
AsiaCountry asiaCountry;
int position = item.size();
asiaCountry = item.get(position);
String nameCountry = asiaCountry.getName();
worldCountryDatabase.QueryData("UPDATE country SET FavoriteCountry = 0 WHERE name =' " + nameCountry);
worldCountryDatabase.close();
}
@Override
public int getItemCount() {
return item.size();
}
public void setFilter(ArrayList<AsiaCountry> arrayList) {
item.clear();
item.addAll(arrayList);
notifyDataSetChanged();
}
public static interface Listener {
public void onClick(int position);
}
public static class ViewHolder extends RecyclerView.ViewHolder {
private ImageView titleImageCountry;
public TextView titleNameCountry;
private ImageButton favoriteCountry;
private ImageButton shareFavoriteCountry;
// Defian the viewHolder
private ViewHolder(View itemView) {
super(itemView);
titleImageCountry = (ImageView) itemView.findViewById(R.id.imageHolder);
titleNameCountry = (TextView) itemView.findViewById(R.id.titleCountry);
favoriteCountry = (ImageButton) itemView.findViewById(R.id.favoriteCountryImage);
shareFavoriteCountry = (ImageButton) itemView.findViewById(R.id.shareFavoriteCountry);
}
// public static class ViewHolder {
private static void clear(View itemView) {
ViewCompat.setAlpha(itemView, 1);
ViewCompat.setTranslationY(itemView, 0);
itemView.setPivotY(itemView.getMeasuredHeight() / 2);
ViewCompat.setScaleX(itemView, 1);
ViewCompat.setScaleY(itemView, 1);
ViewCompat.animate(itemView).setInterpolator(null);
Log.d("Animationg", "Loaded");
}
}
}
我加载了如下所示的项目，点击“赞”按钮时，必须更改为“喜欢”按钮，并将项目添加到收藏项目中。Recylerview items inside fragment
答案 0 :(得分：2)
在您的数据库中， ITEM_TABLE 应该有一个 FAVORITE 列，其中整数值（0 == false和1 == true）。当用户点击“收藏夹”按钮时，将FAVORITE值更改为1.
此外，您应该为您的项目设置一个监听器，因此如果项目FAVORITE值发生变化，将会发生某些事情（按钮设计会发生变化等...）
答案 1 :(得分：1)
另外，您可以添加另一个新表格（favourites_table），并在发生操作后，将在您的表格中添加或删除新项目。
