I made an android application which saves notes. The notes are indeed saved. However when the app is opened only the example note Akhilesh Chobey is shown. All other notes are shown on pressing the back button in the Main2Activity(Activity for editing note)
MainActivity:
public class MainActivity extends AppCompatActivity {
ListView notesListView;
static ArrayList<String> notesArrayList;
static ArrayAdapter<String> adapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
notesListView = (ListView) findViewById(R.id.notesListView);
notesArrayList = new ArrayList<String>();
if(Main2Activity.myDb != null) {
notesArrayList.clear();
Cursor res = Main2Activity.myDb.getData();
if (res.getCount() == 0) {
Log.i("Error", "error");
return;
}
while (res.moveToNext()) {
notesArrayList.add(res.getString(res.getColumnIndex("text")));
}
}
notesArrayList.add("Akhilesh Chobey");
adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, notesArrayList);
notesListView.setAdapter(adapter);
notesListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
Intent intent = new Intent(getApplicationContext(), Main2Activity.class);
intent.putExtra("notePosition", i);
startActivity(intent);
}
});
}
}
Main2Activity:
public class Main2Activity extends AppCompatActivity implements TextWatcher {
static DatabaseOperations myDb;
EditText editNote;
int position;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
editNote = (EditText) findViewById(R.id.noteEditText);
myDb = new DatabaseOperations(Main2Activity.this);
Intent intent = getIntent();
position = intent.getIntExtra("notePosition", -1);
if(position != -1){
editNote.setText(MainActivity.notesArrayList.get(position));
}
editNote.addTextChangedListener(this);
}
#Override
public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
}
#Override
public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
if (myDb != null) {
boolean isInserted = myDb.insertData(editNote.getText().toString());
MainActivity.notesArrayList.set(position, String.valueOf(charSequence));
MainActivity.adapter.notifyDataSetChanged();
}
}
Database Helper Class:
public class DatabaseOperations extends SQLiteOpenHelper {
public static final String DatabaseName = "notes.db";
public static final String TableName = "notes";
public static final String Col1 = "text";
public DatabaseOperations(Context context) {
super(context, DatabaseName, null, 1);
}
#Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("create table " + TableName + " (text TEXT) ");
}
#Override
public void onUpgrade(SQLiteDatabase db, int i, int i1) {
db.execSQL("DROP TABLE IF EXISTS " + TableName);
onCreate(db);
}
public boolean insertData(String note){
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put(Col1, note);
long result = db.insert(TableName, null, contentValues);
if(result == -1){
return false;
}else {
return true;
}
}
public Cursor getData(){
SQLiteDatabase db = this.getWritableDatabase();
Cursor result = db.rawQuery("select * from " + TableName, null);
return result;
}
}
in your Main2Activity class(Terrible naming BTW) the
static DatabaseOperations myDb;
variable is not assigned with anything at the start of the program, so DatabaseOperations== null, so the if condition
if(Main2Activity.myDb != null) {
notesArrayList.clear();
Cursor res = Main2Activity.myDb.getData();
if (res.getCount() == 0) {
Log.i("Error", "error");
return;
}
while (res.moveToNext()) {
notesArrayList.add(res.getString(res.getColumnIndex("text")));
}
}
will not be executed thus no data will be loaded in to the app.
BUT when you come back from the M2A class by pressing back
onCreate is called once again but this time DatabaseOperations myDb != NULL ,because myDb is assigned a value by this,
myDb = new DatabaseOperations(Main2Activity.this);
so the if condition in MainActivity class becomes true.
WHAT YOU HAVE TO DO: find a way to make that myDb variable not null at the start of the program.
Related
I have coded a RecyclerView where I search for data from my SQLiteDatabase with the SearchAdapter. The MaterialSearchBar (PlaceHolder) only shows the names of the data from the Database. Now I want to select one item, which i choose in the searchbar and get all the other columns of that one row and store the data in a listview in another activity.
So my first question is, how can i get all data from one row, if i only have the name? Should I do it with a cursor?
And my second question is, how should i store all the data from that one row in a listview in another activity?
Thank you for your help!
enter cclass SearchViewHolder extends RecyclerView.ViewHolder{
public TextView medid,name,menge,art,nummer;
public SearchViewHolder(View itemView) {
super(itemView);
medid = (TextView) itemView.findViewById(R.id.medid);
name = (TextView) itemView.findViewById(R.id.name);
menge = (TextView) itemView.findViewById(R.id.menge);
art = (TextView) itemView.findViewById(R.id.art);
nummer = (TextView) itemView.findViewById(R.id.nummer);
}
}
public class SearchAdapter extends RecyclerView.Adapter<SearchViewHolder> {
private Context context;
private List<Drugs> drugs;
public SearchAdapter(Context context, List<Drugs> drugs) {
this.context = context;
this.drugs = drugs;
}
public SearchAdapter() {
}
#Override
public SearchViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater inflater =LayoutInflater.from(parent.getContext());
View itemView = inflater.inflate(R.layout.medikamentensuche,parent,false);
return new SearchViewHolder(itemView);
}
#Override
public void onBindViewHolder(SearchViewHolder holder, int position) {
//String pharmaId,name,menge,art,preis,code,bezeichnung;
holder.medid.setText(toString().valueOf(drugs.get(position).getMedID()));
holder.name.setText(drugs.get(position).getName());
holder.menge.setText(drugs.get(position).getMenge());
holder.art.setText(drugs.get(position).getArt());
holder.nummer.setText(drugs.get(position).getNummer());
}
#Override
public int getItemCount() {
return drugs.size();
}
}
DataBaseOpenhelper class
public class DatabaseOpenHelper extends SQLiteAssetHelper {
private static final String DB_NAME = "medikamente.db";
private static final String TABLE = "Medikamente";
private static final int DB_VER = 1;
public static final String ID = "MedID";
public static final String NAME = "Handelsname";
public static final String MENGE = "Mengenangabe";
public static final String ART = "Mengenart";
public static final String NUMMER = "Pharmanummer";
public DatabaseOpenHelper(Context context) {
super(context, DB_NAME, null, DB_VER);
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + TABLE);
onCreate(db);
}
//neues Medikament hinzufügen
public boolean insertNewEntry (String name, String mengenangabe, String mengenart, String pharmanummer) {
SQLiteDatabase db = getWritableDatabase();
ContentValues values = new ContentValues();
values.put(NAME,name);
values.put(MENGE,mengenangabe);
values.put(ART,mengenart);
values.put(NUMMER,pharmanummer);
long result = db.insert("Medikamente",null,values);
if (result == -1)
return false;
else
return true;
}
public List<Drugs> getDrug() {
SQLiteDatabase db = getReadableDatabase();
SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
Log.d("in der DrugDatabases", "SQLiteQueryBuilder successful");
//Kathi habe hier: "ATCCode", "BezeichnungATCCode" gelöscht
String [] sqlSelect = {"MedID", "Handelsname", "Mengenangabe", "Mengenart", "Pharmanummer"};
String tableName = "Medikamente";
Log.d("in der DrugDatabases", " successful" + sqlSelect);
qb.setTables(tableName);
Cursor cursor = qb.query(db, sqlSelect, null, null, null, null, null);
List<Drugs> result = new ArrayList<>();
if(cursor.moveToFirst()) {
do{
Drugs drug = new Drugs();
drug.setMedID(cursor.getInt(cursor.getColumnIndex("MedID")));
drug.setName(cursor.getString(cursor.getColumnIndex("Handelsname")));
drug.setMenge(cursor.getString(cursor.getColumnIndex("Mengenangabe")));
drug.setArt(cursor.getString(cursor.getColumnIndex("Mengenart")));
drug.setNummer(cursor.getString(cursor.getColumnIndex("Pharmanummer")));
result.add(drug);
}while (cursor.moveToNext());
}return result;
}
public List<String> getNames() {
SQLiteDatabase db = getReadableDatabase();
SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
String [] sqlSelect = {"Handelsname" };
String tableName = "Medikamente";
qb.setTables(tableName);
Cursor cursor = qb.query(db, sqlSelect, null, null, null, null, null);
List<String> result = new ArrayList<>();
if(cursor.moveToFirst()) {
do{
result.add(cursor.getString(cursor.getColumnIndex("Handelsname" )));
}while (cursor.moveToNext());
}return result;
}
public List<Drugs> getDrugsByName(String name) {
SQLiteDatabase db = getReadableDatabase();
SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
String [] sqlSelect = {"MedID" ,"Handelsname" ,"Mengenangabe" ,"Mengenart" ,"Pharmanummer"};
String tableName = "Medikamente";
qb.setTables(tableName);
Cursor cursor = qb.query(db, sqlSelect, "Handelsname LIKE ?",new String[]{"%"+name+"%"}, null, null, null);
List<Drugs> result = new ArrayList<>();
if(cursor.moveToFirst()) {
do{
Drugs drug = new Drugs();
drug.setMedID(cursor.getInt(cursor.getColumnIndex("MedID")));
drug.setName(cursor.getString(cursor.getColumnIndex("Handelsname")));
drug.setMenge(cursor.getString(cursor.getColumnIndex("Mengenangabe")));
drug.setArt(cursor.getString(cursor.getColumnIndex("Mengenart")));
drug.setNummer(cursor.getString(cursor.getColumnIndex("Pharmanummer")));
result.add(drug);
}while (cursor.moveToNext());
}return result;
}
}
MedSucheActivity
public class MedSucheActivity extends AppCompatActivity {
RecyclerView recyclerView;
RecyclerView.LayoutManager layoutManager;
SearchAdapter adapter;
TextView textView;
MaterialSearchBar materialSearchBar;
List<String> suggestList = new ArrayList<>();
DatabaseOpenHelper database;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_medsuchen);
Button button = (Button) findViewById(R.id.hinzufügen);
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(getApplicationContext(),MedTableActivity.class);
TextView suche = (TextView) findViewById(R.id.SuchMedikament);
intent.putExtra("weitergabe",suche.getText().toString());
startActivityForResult(intent,1);
//wichtig wenn man Daten zurück geben will von der 2.Activity
}
});
textView = (TextView) findViewById(R.id.SuchMedikament);
recyclerView = (RecyclerView) findViewById(R.id.recycler_search);
layoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(layoutManager);
recyclerView.setHasFixedSize(true);
materialSearchBar = (MaterialSearchBar) findViewById(R.id.search_bar);
//textView = (TextView) findViewById(R.id.versuch);
//Datenbank
database = new DatabaseOpenHelper(this);
//Searchbar
materialSearchBar.setHint("Search");
materialSearchBar.setCardViewElevation(10);
loadSuggestList();
materialSearchBar.addTextChangeListener(new TextWatcher() {
#Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
#Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
List<String> suggest = new ArrayList<>();
for(String search:suggestList) {
if (search.toLowerCase().contains(materialSearchBar.getText().toLowerCase()))
suggest.add(search);
}
materialSearchBar.setLastSuggestions(suggest);
}
#Override
public void afterTextChanged(Editable s) {
}
});
materialSearchBar.setOnSearchActionListener(new MaterialSearchBar.OnSearchActionListener() {
#Override
public void onSearchStateChanged(boolean enabled) {
if(!enabled)
recyclerView.setAdapter(adapter);
}
#Override
public void onSearchConfirmed(CharSequence text) {
startSearch(text.toString());
}
#Override
public void onButtonClicked(int buttonCode) {
}
});
//init Adapter default set all result
adapter = new SearchAdapter(this,database.getDrug());
recyclerView.setAdapter(adapter);
}
private void startSearch(String text) {
adapter = new SearchAdapter(this,database.getDrugsByName(text));
recyclerView.setAdapter(adapter);
}
private void loadSuggestList() {
suggestList = database.getNames();
materialSearchBar.setLastSuggestions(suggestList);
}
public void onHinzuClick(View v) {
Log.d("msg","Auf Hinzufügen Button geklickt");
Intent intent = new Intent (getBaseContext(),MedikamentHinzufugenActivity.class);
startActivity(intent);
}
}
So my first question is, how can i get all data from one row, if i
only have the name?
And my second question is, how should i store all the data from that
one row in a listview in another activity?
If name is definitely going to be unique, which it appears that it may not be, then you can use that in conjunction with the getDrugsByName method to obtain a list of Drug objects (1 if the name is unique). So name is all that would be required and this can be passed to another activity via an Intent Extra and thus retrieved from that Intent Extra, you can then use the getDrugsbyName method in that activity to then get all the data for the row (for 2.). Of course you could also pass all values via Intent Extras.
If name isn't necessarily unique then you could use MedId (column ID) (assuming that it's the PRIMARY KEY of the table and thus unique) instead of the name. You would probably have a method getDrugById in the DatabaseHelper class along the lines of (for 2.) :-
public Drugs getDrugById(long id) {
SQLiteDatabase db = getReadableDatabase();
Drugs rv = new Drugs();
rv.setMedID(-1); // set so that drug not found can be determined
String whereclause = ID + "=?";
String[] whereargs = new String[]{String.valueOf(id)};
Cursor csr = db.query(TABLE,null,whereclause,whereargs,null,null,null);
if (csr.moveToFirst()) {
rv.setMedID(id);
rv.setName(csr.getString(csr.getColumnIndex(NAME)));
rv.setMenge(csr.getString(csr.getColumnIndex(MENGE)));
rv.setArt(csr.getString(csr.getColumnIndex(ART)));
rv.setNummer(csr.getString(csr.getColumnIndex(NUMMER)));
}
csr.close();
return rv;
}
Notes
The returned value should be checked for the MedID being -1, this indicating that there is no such row that matches the passed id.
Rather than risking mistyping names the CONSTANTS defined in the class have been used (you may wish to adopt this throughout).
Cursors should ALWAYS be closed when done with, otherwise an exception can occur.
The above assumes that the ID column is the PRIMARY KEY and that it is an alias of the rowid column. That is you have ID INTEGER PRIMARY KEY or ID INTEGER,..other columns.., PRIMARY KEY (ID)
The above assumes the correct usage of the ID column i.e. that it is treated as a long not an int (int is ok as long as the rows are limited, however SQLite allows rowid's as high as 9223372036854775807, which cannot be handled by an int).
This is the usual method, as using an alias of rowid will likely be the most efficient.
I have a problem with recycler, the problem is: I have AsyncTask which query data from my db, and then updating recycler by CursorLoader, but adapter doesn't fill recycler, Logs says that the data from db is successfully reading and then Adapter constructor successfully takes ArrayList with data, but that's all, logs says that adapter's methods doesn't call.
MainActivity :
public class MainActivity extends AppCompatActivity implements LoaderManager.LoaderCallbacks<Cursor> {
private SQLiteDatabase db;
private SimpleCursorLoader loader;
private MySimpleAdapter adapter;
private RecyclerView recycler;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
recycler = (RecyclerView) findViewById(R.id.recycler);
new SimpleTask(SimpleTask.OPEN, null).execute();
}
private class SimpleTask extends AsyncTask<Void, Void, Void> {
public static final int INSERT = 0;
public static final int DELETE = 1;
public static final int OPEN = 2;
private int task;
private String name;
public SimpleTask(int task, String name) {
this.task = task;
this.name = name;
}
#Override
protected Void doInBackground(Void... params) {
switch (task) {
case INSERT :
ContentValues values = new ContentValues();
values.put(SimpleHelper.KEY_NAME, name);
db.insert(SimpleHelper.TABLE_NAME, null, values);
break;
case DELETE :
db.delete(SimpleHelper.TABLE_NAME, SimpleHelper.KEY_NAME + " = ? ", new String[]{name});
break;
case OPEN :
if (db == null) {
try {
db = new SimpleHelper(MainActivity.this).getWritableDatabase();
} catch (SQLiteException e) {
e.printStackTrace();
}
}
break;
}
return null;
}
#Override
protected void onPostExecute(Void aVoid) {
if (loader == null) {
loader = new SimpleCursorLoader(MainActivity.this, db);
loader.setQueryParams(SimpleHelper.TABLE_NAME, new String[]{SimpleHelper.KEY_NAME},
null, null);
getSupportLoaderManager().initLoader(0, null, MainActivity.this);
}
getSupportLoaderManager().getLoader(0).forceLoad();
}
}
#Override
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
return loader;
}
#Override
public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
Log.i("MyLog", "onLoadFinished cursor size is " + data.getCount());
List<String> items = new ArrayList<>();
data.moveToFirst();
do {
items.add(data.getString(0));
Log.i("MyLog", data.getString(0));
} while (data.moveToNext());
Log.i("MyLog", "onLoadFinished items size is " + items.size());
if (adapter == null) {
adapter = new MySimpleAdapter(items);
recycler.setAdapter(adapter);
} else {
adapter.updateAdapter(items);
}
}
#Override
public void onLoaderReset(Loader<Cursor> loader) {
}
private class MySimpleAdapter extends RecyclerView.Adapter<MySimpleAdapter.MyHolder> {
private List<String> items;
public MySimpleAdapter(List<String> items) {
Log.i("MyLog", "Constructor called with items size " + items.size());
this.items = items;
}
public class MyHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
TextView tvText;
public MyHolder(View itemView) {
super(itemView);
tvText = (TextView) itemView.findViewById(android.R.id.text1);
itemView.setOnClickListener(this);
}
#Override
public void onClick(View v) {
new SimpleTask(SimpleTask.DELETE, tvText.getText().toString());
}
}
public void updateAdapter(List<String> items) {
this.items = items;
notifyDataSetChanged();
}
#Override
public MyHolder onCreateViewHolder(ViewGroup parent, int viewType) {
Log.i("MyLog", "onCreateViewHolder");
View view = LayoutInflater.from(parent.getContext()).inflate(android.R.layout.simple_list_item_1, null, false);
return new MyHolder(view);
}
#Override
public void onBindViewHolder(MyHolder holder, int position) {
holder.tvText.setText(items.get(position));
Log.i("MyLog", "onBindViewHolder setText : " + items.get(position));
}
#Override
public int getItemCount() {
Log.d("MyLog", "getItemCount called with size : " + items.size());
return items.size();
}
}
SimpleCursorLoader :
public class SimpleCursorLoader extends CursorLoader {
private SQLiteDatabase db;
private String tableName;
private String[] columns;
public SimpleCursorLoader(Context context, SQLiteDatabase db) {
super(context);
this.db = db;
}
public void setQueryParams(String tableName, String[] columns, String selection, String[] selectionArgs) {
this.tableName = tableName;
this.columns = columns;
setSelection(selection);
setSelectionArgs(selectionArgs);
}
#Override
public Cursor loadInBackground() {
Cursor cursor = db.query(tableName, columns, getSelection(), getSelectionArgs(),
null, null, null);
return cursor;
}
DBHelper :
public class SimpleHelper extends SQLiteOpenHelper{
public static final String TABLE_NAME = "users";
public static final String KEY_NAME = "name";
public static final String KEY_ID = "_id";
private static final int DB_VERSION = 1;
private static final String DB_NAME = "SimpleDB";
public SimpleHelper(Context context) {
super(context, DB_NAME, null, DB_VERSION);
}
#Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("create table " + TABLE_NAME + "("
+ KEY_ID + " integer primary key autoincrement, "
+ KEY_NAME + " text)");
for (int i = 0; i < 5; i ++) {
ContentValues values = new ContentValues();
values.put(KEY_NAME, "name" + i+1);
db.insert(TABLE_NAME, null, values);
Log.i("MyLog", "inserted");
}
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
activity_main.xml :
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.RecyclerView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/recycler"
android:layout_width="match_parent"
android:layout_height="match_parent" />
Use this.
recycler.setLayoutManager(new LinearLayoutManager(this));
recycler.setHasFixedSize(true);
recycler.setNestedScrollingEnabled(false);
I am facing this problem whenever i run the app 1st time data in database remain single time but when i close the App and restart again data goes twice(means two same row in table).Similarly for 3rd, 4th time and so on. How do i get rid of this problem? I even put datas.clear in DataList.java but don't whether i have add the datas.clear() line in correct place or not.
PLz help if there is any other problem in my code.
MainActivity.java code
public class MainActivity extends AppCompatActivity {
Button listButton, addButton;
DatabaseHelper df;
private final static String TAG = "TestActivity";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
df = new DatabaseHelper(this);
addButton = (Button) findViewById(R.id.addbutton);
uploadList();
}
public void uploadList(){
DatabaseHelper df=new DatabaseHelper(this);
df.open();
try{
InputStream im=getResources().getAssets().open("testdata.csv");
BufferedReader br=new BufferedReader(new InputStreamReader(im));
String data=br.readLine();
while(data != null){
String t[]=data.split(",");
Product p=new Product();
p.setFirst(t[0]);
p.setSec(t[1]);
p.setThird(t[2]);
df.insert(p);
data=br.readLine();
}
}catch(Exception e){
}
}
}
DatabaseHelper.java code
public class DatabaseHelper extends SQLiteOpenHelper{
private static final String FIRST="Name";
private static final String SECOND="Issn";
private static final String THIRD="ImpactFactor";
private static final String DATABASE="journal2016";
private static final String TABLENAME="journal";
private static final int VERSION=1;
SQLiteDatabase sd;
public void open(){
sd=getWritableDatabase();
}
public void close(){
sd.close();
}
public DatabaseHelper(Context context) {
super(context, DATABASE, null, VERSION);
}
#Override
public void onCreate(SQLiteDatabase sqLiteDatabase) {
sqLiteDatabase.execSQL("DROP TABLE IF EXISTS " + TABLENAME );
sqLiteDatabase.execSQL("CREATE TABLE " + TABLENAME + " ( NAME TEXT, ISSN TEXT, IMPACTFACTOR REAL)");
}
#Override
public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
sqLiteDatabase.execSQL("DROP TABLE IF EXISTS " + TABLENAME );
}
public long insert(Product p){
ContentValues cv=new ContentValues();
cv.put(FIRST, p.getFirst());
cv.put(SECOND, p.getSec());
cv.put(THIRD, p.getThird());
return sd.insertWithOnConflict(TABLENAME, null, cv,SQLiteDatabase.CONFLICT_REPLACE);
}
public List<Product> getAllProduct(){
ArrayList<Product> list=new ArrayList<Product>();
SQLiteDatabase db = this.getWritableDatabase();
Cursor c=db.rawQuery("SELECT * FROM " + TABLENAME, null);
while(c.moveToNext()){
Product p=new Product();
p.setFirst(c.getString(0));
p.setSec(c.getString(1));
p.setThird(c.getString(2));
list.add(p);
}
db.close();
return list;
}
}
DataList.java code
public class DataList extends Activity{
List<Product> datas = new ArrayList<Product>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.list);
datas.clear();
DatabaseHelper d=new DatabaseHelper(this);
d.open();
datas = d.getAllProduct();
ListView lv=(ListView)findViewById(R.id.listView1);
lv.setAdapter(new ArrayAdapter(this, android.R.layout.simple_list_item_1, datas));
}
}
Product.java
public class Product {
private String first;
private String second;
private String third;
public String getFirst() {
return first;
}
public void setFirst(String first) {
this.first = first;
}
public String getSec() {
return second;
}
public void setSec(String sec) {
this.second = sec;
}
public String getThird() {
return third;
}
public void setThird(String third) {
this.third = third;
}
#Override
public String toString() {
return first + second + third;
}
}
Remove this line from your onCreate() method:
df = new DatabaseHelper(this);
as no need of it because you are create object of your DatabaseHelper class inside uploadList() method.
And also you are calling uploadList() method inside onCreate() thats why every time you launch the app, the onCreate() method executes and you uploadList() also execute. Try to put its calling statement in an onClickListener so it happens when you click a button or your choice of stuff.
I have a listview and a SQL database. In my SQL database, there is a title and a content field. I display titles on a listview. Now this is what I'm trying to achieve: When I click the title, this should pass me to another activity and in this activity I want to see relative content in edittext. And sorry for my poor English.
This is my code.
DB CLASS.
public class NoteAlDatabase extends SQLiteOpenHelper {
private static final String VERITABANI_ISMI = "veritabanim2.db";
private static final int VERITABANI_VERSION = 1;
private static final String TABLO_ISMI = "noteAlTablosu";
public static final String ID = "_id";
public static final String NOTEBASLIK= "noteTitle";
public static final String NOTEICERIK = "noteContent";
final Context c;
private SQLiteDatabase db;
public NoteAlDatabase(Context context) {
super(context, VERITABANI_ISMI, null, VERITABANI_VERSION);
this.c = context;
}
#Override
public void onCreate(SQLiteDatabase db) {
String tablo_olustur = "CREATE TABLE " + TABLO_ISMI +
" ("+ID+" INTEGER PRIMARY KEY AUTOINCREMENT, "+
NOTEBASLIK + " TEXT, " +
NOTEICERIK + " TEXT);";
db.execSQL(tablo_olustur);
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXIST " + TABLO_ISMI);
onCreate(db);
}
public NoteAlDatabase abrirBaseDeDatos() throws SQLException {
NoteAlDatabase noteAlDatabase = new NoteAlDatabase(c);
noteAlDatabase.getWritableDatabase();
return this;
}
public long addReminder(NoteAlModel noteAl) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues cv = new ContentValues();
cv.put(ID, noteAl.getNoteAlID());
cv.put(NOTEBASLIK, noteAl.getNoteAlBaslik());
cv.put(NOTEICERIK, noteAl.getNoteAlIcerik());
// tarih'te eklenecek /long cinsinden
long id = db.insert(TABLO_ISMI,null,cv);
db.close();
return id;
}
public List<NoteAlModel> AllData() {
SQLiteDatabase db = this.getReadableDatabase();
String[] sutunlar = new String[]{ID,NOTEBASLIK,NOTEICERIK};
Cursor c =db.query(TABLO_ISMI, sutunlar,null,null,null,null,null);
int idsirano = c.getColumnIndex(ID);
int basliksirano = c.getColumnIndex(NOTEBASLIK);
int iceriksirano = c.getColumnIndex(NOTEICERIK);
List<NoteAlModel> liste = new ArrayList<NoteAlModel>();
for (c.moveToFirst();!c.isAfterLast();c.moveToNext()){
NoteAlModel noteAlModel = new NoteAlModel();
noteAlModel.setNoteAlID(c.getString(idsirano));
noteAlModel.setNoteAlBaslik(c.getString(basliksirano));
noteAlModel.setNoteAlIcerik(c.getString(iceriksirano));
liste.add(noteAlModel);
}
db.close();
return liste;
}
public void Sil(){
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLO_ISMI, null, null);
}
ListViewActivity:
public class NoteListele extends AppCompatActivity {
ListView listView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_note_listele);
Button btn = (Button) findViewById(R.id.btnYeniNotKaydet);
btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(NoteListele.this, NoteAlActivity.class);
startActivity(intent);
}
});
try {
displayListview();
} catch (Exception e) {
Toast.makeText(NoteListele.this, "Listelenecek veri bulunmamakta", Toast.LENGTH_SHORT).show();
}
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
}
});
}
public void displayListview() {
NoteAlDatabase db = new NoteAlDatabase(getApplicationContext());
List<NoteAlModel> liste = new ArrayList<NoteAlModel>();
liste = db.AllData();
ArrayAdapter arrayAdapter = new ArrayAdapter<NoteAlModel>(this, android.R.layout.simple_list_item_1, liste);
listView.setAdapter(arrayAdapter);
}
public void deleteAllData(View view) {
NoteAlDatabase db = new NoteAlDatabase(getApplicationContext());
db.Sil();
//displayListview();
}
GETSET Model:
public class NoteAlModel {
private String noteAlID;
private String noteAlBaslik;
private String noteAlIcerik;
public NoteAlModel() {
}
public NoteAlModel(String noteAlID, String noteAlBaslik, String noteAlIcerik) {
this.noteAlID = noteAlID;
this.noteAlBaslik = noteAlBaslik;
this.noteAlIcerik = noteAlIcerik;
}
public NoteAlModel(String noteAlBaslik, String noteAlIcerik) {
this.noteAlBaslik = noteAlBaslik;
this.noteAlIcerik = noteAlIcerik;
}
public String getNoteAlID() {
return noteAlID;
}
public void setNoteAlID(String noteAlID) {
this.noteAlID = noteAlID;
}
public String getNoteAlBaslik() {
return noteAlBaslik;
}
public void setNoteAlBaslik(String noteAlBaslik) {
this.noteAlBaslik = noteAlBaslik;
}
public String getNoteAlIcerik() {
return noteAlIcerik;
}
public void setNoteAlIcerik(String noteAlIcerik) {
this.noteAlIcerik = noteAlIcerik;
}
logcat
03-06 20:16:46.095 4886-4886/reminderplus.reminder2 E/AndroidRuntime: FATAL EXCEPTION: main
Process: reminderplus.reminder2, PID: 4886
java.lang.NoSuchMethodError: No virtual method AllData()Landroid/database/Cursor; in class Lreminderplus/reminder2/veritabani/NoteAlDatabase; or its super classes (declaration of 'reminderplus.reminder2.veritabani.NoteAlDatabase' appears in /data/data/reminderplus.reminder2/files/instant-run/dex/slice-slice_9_4376acd355cb0a9e536cff445d1b4b60f3d0940d-classes.dex)
at reminderplus.reminder2.noteal.NoteListele.onCreate(NoteListele.java:46)
at android.app.Activity.performCreate(Activity.java:6237)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
You have not to convert your Cursor into List<NoteAlModel>. You can use Cursor with SimpleCursorAdapter.
In this case your AllData Method will look like:
public Cursor AllData() {
SQLiteDatabase db = this.getReadableDatabase();
String[] sutunlar = new String[]{ID,NOTEBASLIK,NOTEICERIK};
Cursor c = db.query(TABLO_ISMI, sutunlar,null,null,null,null,null);
db.close();
return c;
}
Then you create a SimpleCursorAdapter and set it to your ListView
SimpleCursorAdapter adapter = new SimpleCursorAdapter(this,
android.R.layout.simple_list_item_1,
db.AllData(),
new String[] { NoteAlDatabase.NOTEBASLIK },
new int[] { android.R.id.text1 });
listView.setAdapter(scAdapter);
After that you have a ListView with your "titles" and now let's manage your setOnItemClickListener to open a "content" in new activtiy.
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
String content = ((SimpleCursorAdapter)parent.getAdapter()).
getCursor().getString(NoteAlDatabase.NOTEICERIK);
Intent intent = new Intent(getApplicationContext(), ContentActivity.class);
intent.putExtra("PARAM", content);
startActivity(intent);
}
});
And now you can obtain the content in ContentActivity's onCreate method
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_content);
//...
String content = getIntent().getExtras().getString("PARAM", "");
// show content in some `TextView`
}
I am building an app that displays items in a ListFragment. Right now each item displays the title and creation date. There are two other fragments. One that creates an item and has a EditText field where i can edit the title. Another simply displays an individual items contents.
The issue I am having is that every time I enter a character in the EditText field the app closes. The error messages indicate that the error occurs at onTextChanged in the TextChangedListener. Since I had this feature working when I was storing everything as a JSON file the error must occur because of the way i am updating the database and updating my model layer.
This file performs all the database operations and creates a custom Cursor.
public class SnapDatabaseHelper extends SQLiteOpenHelper {
private static final String TAG = "FeedFragment";
private static final String DB_NAME = "snap.sqlite";
private static final int VERSION = 1;
private static final String TABLE_SNAP = "snap";
private static final String COLUMN_SNAP_ID = "_id";
private static final String COLUMN_SNAP_DATE = "snap_date";
private static final String COLUMN_SNAP_UUID = "snap_uuid";
private static final String COLUMN_SNAP_TITLE = "snap_title";
public SnapDatabaseHelper(Context context){
super(context, DB_NAME, null, VERSION);
}
#Override
public void onCreate(SQLiteDatabase db) {
// Create SNAP table
db.execSQL("create table snap(" +
"_id integer primary key autoincrement, " +
//"snap_uuid text, " +
"snap_date integer, " +
"snap_title text) ");
}
#Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
//
}
public long insertSnap(Snap snap){
ContentValues cv = new ContentValues();
//cv.put(COLUMN_SNAP_UUID, snap.getUniqueId().toString());
cv.put(COLUMN_SNAP_DATE, snap.getDate().getTime());
cv.put(COLUMN_SNAP_TITLE, "");
return getWritableDatabase().insert(TABLE_SNAP, null, cv);
}
public boolean updateTitle(long snapId, String text)
{
ContentValues cv = new ContentValues();
cv.put(COLUMN_SNAP_ID, snapId);
cv.put(COLUMN_SNAP_TITLE, text);
int i= getWritableDatabase().update(TABLE_SNAP, cv, COLUMN_SNAP_ID+ "=" + snapId, null);
return i>0;
}
public SnapCursor querySnap(long id) {
Cursor wrapped = getReadableDatabase().query(TABLE_SNAP,
null, // all columns
COLUMN_SNAP_ID + " = ?", // look for a run ID
new String[]{ String.valueOf(id) }, // with this value
null, // group by
null, // order by
null, // having
"1"); // limit 1 row
return new SnapCursor(wrapped);
}
public SnapCursor querySnaps() {
// equivalent to "select * from run order by start_date asc"
Cursor wrapped = getReadableDatabase().query(TABLE_SNAP,
null, null, null, null, null, COLUMN_SNAP_DATE + " asc");
return new SnapCursor(wrapped);
}
public static class SnapCursor extends CursorWrapper{
public SnapCursor(Cursor c){
super(c);
}
public Snap getSnap() {
if (isBeforeFirst() || isAfterLast())
return null;
Snap s = new Snap();
s.setId(getLong(getColumnIndex(COLUMN_SNAP_ID)));
//s.setUniqueId(UUID(getString(getColumnIndex(COLUMN_SNAP_UUID))));
s.setDate(new Date(getLong(getColumnIndex(COLUMN_SNAP_DATE))));
s.setTitle(getString(getColumnIndex(COLUMN_SNAP_TITLE)));
return s;
}
}
}
This file links the fragments to the DatabaseHelper.
public class SnapLab {
private static SnapLab sSnapLab;
private Context mAppContext;
private SnapDatabaseHelper mHelper;
// private constructor
private SnapLab(Context appContext){
mAppContext = appContext;
mHelper = new SnapDatabaseHelper(mAppContext);
}
public static SnapLab get(Context c){
if(sSnapLab == null){
sSnapLab = new SnapLab(c.getApplicationContext());
}
return sSnapLab;
}
public Snap insertSnap() {
Snap s = new Snap();
s.setId(mHelper.insertSnap(s));
return s;
}
public boolean updateTitle(long snapId, String text){
return mHelper.updateTitle(snapId, text);
}
public SnapCursor querySnaps() {
return mHelper.querySnaps();
}
public Snap getSnap(long id) {
Snap s = null;
SnapCursor cursor = mHelper.querySnap(id);
cursor.moveToFirst();
// if we got a row, get a run
if (!cursor.isAfterLast())
s = cursor.getSnap();
cursor.close();
return s;
}
}
Here is the fragment with the EditText field
public class EditPageFragment extends Fragment {
private static final String TAG = "EditPageFragment";
public static final String EXTRA_SNAP_ID = "SNAP_ID";
private SnapLab mSnapLab;
private Snap mSnap;
private SnapDatabaseHelper mHelper;
private EditText mSnapText;
private Button mUploadButton;
private TextView mDateText;
private Long snapId;
public static EditPageFragment newInstance(Long snapId){
Bundle args = new Bundle();
args.putLong(EXTRA_SNAP_ID, snapId);
EditPageFragment fragment = new EditPageFragment();
fragment.setArguments(args);
return fragment;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setRetainInstance(true);
mSnapLab = SnapLab.get(getActivity());
Bundle args = getArguments();
if (args != null){
long snapId = args.getLong(EXTRA_SNAP_ID, -1);
if (snapId != -1){
mSnap = mSnapLab.getSnap(snapId);
}
}
mSnap = new Snap();
mSnap = mSnapLab.insertSnap();
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup parent, Bundle savedInstanceState){
View v = inflater.inflate(R.layout.edit_fragment, parent, false);
mDateText = (TextView)v.findViewById(R.id.edit_dateText);
mDateText.setText(mSnap.getDate().toString());
mSnapText = (EditText)v.findViewById(R.id.edit_snapText);
mSnapText.addTextChangedListener(new TextWatcher(){
#Override
public void afterTextChanged(Editable s) {
//leave blank for now
}
#Override
public void beforeTextChanged(CharSequence c, int start, int count,
int after) {
//leave blank for now
}
#Override
public void onTextChanged(CharSequence c, int start, int before,
int count) {
mSnap.setTitle(c.toString());
mSnapLab.updateTitle(snapId, c.toString());
Log.i(TAG, "text saved");
}
});
return v;
}
}
The import bits of code are the updateTitle() functions. What could I be doing wrong. Do you have a suggestion on how to better update a database. Everything works great except for the updating of the title. I appreciate any bit of help.
Looks like snapId is not assigned
private Long snapId; //field
few lines later
long snapId = args.getLong(EXTRA_SNAP_ID, -1); //local variable
few lines later
mSnapLab.updateTitle(snapId, c.toString()); //field
Please add stacktrace next time.