I have created an app witch uses sqlite database to display data. i can read the data and display it in two activities but i cant store or delete the data . i want to save and remove the bookmarks in another table.
i have searched a lot on internet , watched a lot of videos but nothing helps.
Here is my DatabaseHelper.
public class DatabaseHelper extends SQLiteOpenHelper {
private static final String DB_NAME = "mydic.db";
private static final int DB_VERSION = 1;
private String DB_PATH = null;
private static final String TABLE_DICTIONARY = "dictionary1";
public static final String TABLE_BOOKMARK= "bookmark";
private static final String COLUMN_ID = "id";
public static final String COL_WORD = "word";
public static final String COL_DEFINITION = "definition";
private Context mcontext;
private SQLiteDatabase mDatabase;
public DatabaseHelper( Context context) {
super(context, DB_NAME, null, DB_VERSION);
this.mcontext = context;
this.DB_PATH = "/data/data/" + context.getPackageName() + "/" + "databases/";
}
public void createDataBase() throws IOException {
boolean dbExist = checkDataBase();
if (!dbExist) {
this.getReadableDatabase();
try {
mcontext.deleteDatabase(DB_NAME);
copyDataBase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
public boolean checkDataBase() {
SQLiteDatabase checkDB = null;
try {
String myPath = DB_PATH + DB_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
} catch (SQLiteException e) {
e.printStackTrace();
}
if (checkDB != null) {
checkDB.close();
}
return checkDB != null ? true : false;
}
private void copyDataBase() throws IOException {
InputStream myInput = mcontext.getAssets().open(DB_NAME);
String outFileName = DB_PATH + DB_NAME;
OutputStream myOutput = new FileOutputStream(outFileName);
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer)) > 0) {
myOutput.write(buffer, 0, length);
}
myOutput.flush();
myOutput.close();
myInput.close();
}
public void openDatabase() throws SQLException {
String myPath = DB_PATH + DB_NAME;
mDatabase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE);
}
@Override
public synchronized void close() {
if (mDatabase != null)
mDatabase.close();
super.close();
}
public Cursor getListWord(String wordSearch) {
String query = "SELECT * FROM " + TABLE_DICTIONARY + " Where word Like ? " ;
Cursor cursor = null;
try {
openDatabase();
String[] args = {"%"+wordSearch+"%"};
cursor = mDatabase.rawQuery(query , args);
}catch (Exception e){
e.printStackTrace();
}
return cursor;
}
public boolean addBookmark(String title, String subtitle) {
// Gets the data repository in write mode
SQLiteDatabase db = getWritableDatabase();
// Create a new map of values, where column names are the keys
ContentValues values = new ContentValues();
values.put(DatabaseHelper.COL_WORD, title);
values.put(DatabaseHelper.COL_DEFINITION, subtitle);
// Insert the new row, returning the primary key value of the new row
db.insert(DatabaseHelper.TABLE_BOOKMARK, null, values);
return true;
}
public void removeBookmark(String title, String subtitle) {
mDatabase = this.getReadableDatabase();
mDatabase.execSQL("delete from favourites where word Like ? ");
mDatabase.close();
}
public Cursor getBookmarkWord(String wordSearch) {
String query = "SELECT * FROM favourites Where word Like ? " ;
Cursor cursor = null;
try {
openDatabase();
String[] args = {"%"+wordSearch+"%"};
cursor = mDatabase.rawQuery(query , args);
}catch (Exception e){
e.printStackTrace();
}
return cursor;
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE favourites ( id INTEGER PRIMARY KEY AUTOINCREMENT,word,definition)" );
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
if (newVersion > oldVersion) {
try {
copyDataBase();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
Here is my adapter
word = itemView.findViewById(R.id.wordText);
itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int position = getAdapterPosition();
cursor.moveToPosition(position);
Intent intent = new Intent(context, DetailActivity.class);
intent.putExtra("WORD",cursor.getString(1));
intent.putExtra("DEFINITION",cursor.getString(2));
context.startActivity(intent);
and here is my detail activity.
public class DetailActivity extends AppCompatActivity {
private TextToSpeech tts;
DatabaseHelper mDBHelper;
Context context;
DictionaryAdapter dictionaryAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_detail);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
final String word = getIntent().getStringExtra("WORD");
final String definition = getIntent().getStringExtra("DEFINITION");
final TextView tvWordDetail = findViewById(R.id.tvWordDetail);
WebView wordDefinition = findViewById(R.id.tvWordDefinition);
final ImageButton btnBookmark = findViewById(R.id.btnBookmark);
ImageButton textToSpeech = findViewById(R.id.textToSpeech);
Cursor bookmarkWord = mDBHelper.getBookmarkWord("");
int isMark = bookmarkWord == null? 0 : 1;
btnBookmark.setTag(isMark);
int icon = bookmarkWord == null? R.drawable.ic_bookmark_border:R.drawable.ic_bookmark_fill;
btnBookmark.setImageResource(icon);
tvWordDetail.setText(Html.fromHtml(word));
wordDefinition.loadDataWithBaseURL(null,definition,"text/html", "utf-8",null);
btnBookmark.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int i = (int) btnBookmark.getTag();
if (i == 0) {
btnBookmark.setBackgroundResource(R.drawable.ic_bookmark_fill);
btnBookmark.setTag(1);
mDBHelper.addBookmark(word,definition);
} else if (i == 1){
btnBookmark.setBackgroundResource(R.drawable.ic_bookmark_border);
btnBookmark.setTag(0);
mDBHelper.removeBookmark(word,definition);
}
}
});
@Override
public boolean onCreateOptionsMenu(Menu menu) {
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id== android.R.id.home){
onBackPressed();
return true;
}
return super.onOptionsItemSelected(item);
}
}
Here is my log
2019-02-19 15:08:08.727 11561-11561/com.elytelabs.testnav E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.elytelabs.testnav, PID: 11561
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.elytelabs.testnav/com.elytelabs.testnav.DetailActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.database.Cursor com.elytelabs.testnav.database.DatabaseHelper.getBookmarkWord(java.lang.String)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2913)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3048)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1808)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6669)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.database.Cursor com.elytelabs.testnav.database.DatabaseHelper.getBookmarkWord(java.lang.String)' on a null object reference
at com.elytelabs.testnav.DetailActivity.onCreate(DetailActivity.java:54)
at android.app.Activity.performCreate(Activity.java:7136)
at android.app.Activity.performCreate(Activity.java:7127)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1271)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2893)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3048)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1808)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6669)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
