Pass Listview elements to a TextView

Question

Pass Listview elements to a TextView

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#1 by (0 votes)

0

Good, in my code I have an adapter that contains elements of my database, which I want to insert in textviews of another activity (with ids), the problem is that NullPointException throws me, the original idea was to directly pass the data from the sqlite to the textview but I did not find the way to access the values of the database, so I passed it to an array and it does not work, please if anyone knows how to solve this, I attach code. I also have the doubt about which layout I should display in setContentView (R.layout.activity_list); (Since text view is created in xml_activity) The error arises in Select with the listview.getChild

ListActivity (pass data to textviews)

   @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_list);


    listView=(ListView) findViewById(R.id.ltvListaEventos);



    BDSQLite bd= new BDSQLite(getApplicationContext(), "Horario", null,1);
    db= bd.getReadableDatabase();
    String sql="select * from Horario";
    Cursor c;
    String ora;
    try {
        c=db.rawQuery(sql,null);
        arrayAdapter= new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1);
        if(c==null||c.getCount()==0) {
            Toast.makeText(getBaseContext(), "No hay eventos disponibles", Toast.LENGTH_LONG).show();
        }




        if(c.moveToFirst()){
            do {
                ora=c.getString(1);
                arrayAdapter.add(ora);
            } while(c.moveToNext());
            listView.setAdapter(arrayAdapter);
        }

    }catch (Exception ex) {
        Toast.makeText(getApplication(), "Error: "+ex.getMessage(), Toast.LENGTH_SHORT).show();
        this.finish();

    }


   // int count = listView.getAdapter().getCount();
    for(int i = 0; i <= 5; i = i + 1)
    {


        String Select= (String) listView.getChildAt(i).toString();
        if (i==0){
            TextView TEXTO11=(TextView) findViewById(R.id.t11);
            TEXTO11.setText(Select);


        }




    }


    }

error:

ava.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.marcela.sqlitetet/com.example.marcela.sqlitetet.ListActivity}: java.lang.NullPointerException
                                                                             at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2193)
                                                                             at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2243)
                                                                             at android.app.ActivityThread.access$800(ActivityThread.java:135)
                                                                             at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
                                                                             at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                             at android.os.Looper.loop(Looper.java:136)
                                                                             at android.app.ActivityThread.main(ActivityThread.java:5019)
                                                                             at java.lang.reflect.Method.invokeNative(Native Method)
                                                                             at java.lang.reflect.Method.invoke(Method.java:515)
                                                                             at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
                                                                             at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
                                                                             at dalvik.system.NativeStart.main(Native Method)
                                                                          Caused by: java.lang.NullPointerException
                                                                             at com.example.marcela.sqlitetet.ListActivity.onCreate(ListActivity.java:70)

EDIT:

public class ListActivity extends AppCompatActivity {
//al mantener la wea apretada
private SQLiteDatabase db;
private ListView listView;
private ArrayAdapter<String> arrayAdapter;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_list);
    setContentView(R.layout.activity_horario);

    listView=(ListView) findViewById(R.id.ltvListaEventos);



    BDSQLite bd= new BDSQLite(getApplicationContext(), "Horario", null,1);
    db= bd.getReadableDatabase();
    String sql="select * from Horario";
    Cursor c;
    String ora;
    try {
        c=db.rawQuery(sql,null);
        arrayAdapter= new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1);
        if(c==null||c.getCount()==0) {
            Toast.makeText(getBaseContext(), "No hay eventos disponibles", Toast.LENGTH_LONG).show();
        }




        if(c.moveToFirst()){
            do {
                ora=c.getString(1);
                arrayAdapter.add(ora);
            } while(c.moveToNext());
            listView.setAdapter(arrayAdapter);
        }

    }catch (Exception ex) {
        Toast.makeText(getApplication(), "Error: "+ex.getMessage(), Toast.LENGTH_SHORT).show();
        this.finish();

    }


   int count = listView.getAdapter().getCount();
    for(int i = 0; i <= count; i = i ++)
    {
        if (i==0){
           TextView TEXTO11=(TextView) findViewById(R.id.t11);
           TEXTO11.setText(listView.get(i));
        }
    }






}





}

Activity schedule (has the textview, attached fragment of the code).

<TableRow
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_weight="1"
    android:background="#000000"
    android:id="@+id/fila1">

    <TextView
        android:layout_width="44dp"
        android:layout_height="match_parent"
        android:layout_column="0"
        android:layout_margin="1dp"
        android:background="#FFFFFF"
        android:gravity="center"
        android:text="@string/bloque_12"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:textSize="10sp"
        />


    <TextView
        android:layout_width="7dp"
        android:layout_height="match_parent"
        android:layout_column="1"
        android:layout_margin="1dp"
        android:background="#FFFFFF"
        android:gravity="center"
        android:text=""
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:id="@+id/t11"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_column="2"
        android:layout_margin="1dp"
        android:background="#FFFFFF"
        android:gravity="center"
        android:text=""
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:id="@+id/t12"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_column="2"
        android:layout_margin="1dp"
        android:background="#FFFFFF"
        android:gravity="center"
        android:text=""
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:id="@+id/t13"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_column="2"
        android:layout_margin="1dp"
        android:background="#FFFFFF"
        android:gravity="center"
        android:text=""
        android:id="@+id/t14"
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_column="2"
        android:layout_margin="1dp"
        android:background="#FFFFFF"
        android:gravity="center"
        android:text=""
        android:id="@+id/t15"
        android:textAppearance="?android:attr/textAppearanceLarge" />


</TableRow>

Activity timetable:

   @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_horario);

    Button boton = (Button) findViewById(R.id.boton1);
    boton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent i = new Intent(HORARIOActivity.this, Editar.class);
            startActivity(i);

        }
    });


}

}

java android

asked by Nicolas Oporto 20.12.2017 в 12:09

source

1 answer

Bring data from an SQLite to a TextView (TableRow Content) Scroll does not work in Android WebView

score 0 · Answer 1

Instead of using listView.getChildAt(i).toString(); Try to create an array that will contain the database elements:

//...
Cursor c;
String ora;
ArrayList<String> datos = new ArrayList<String>();

try {
  //...

Now, when you get the data from the database, you add it to the list:

//...

if(c.moveToFirst()){
    do {
        ora=c.getString(1);
        arrayAdapter.add(ora);

        //agregamos el elemento al array
        datos.add(ora)
    } while(c.moveToNext());
    listView.setAdapter(arrayAdapter);
}

//...

Then now you would only have access to the elements using the get () method of the list:

//...
for(int = 0; i < datos.size(); i++)
{

    if (i==0){
        TextView TEXTO11=(TextView) findViewById(R.id.t11);

        // le asigamos el texto al TEXT11
        TEXTO11.setText(datos.get(i));
    }
}

//...

Complete code of the method onCreate() :

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_list);
    setContentView(R.layout.activity_horario);

    listView=(ListView) findViewById(R.id.ltvListaEventos);


    BDSQLite bd= new BDSQLite(getApplicationContext(), "Horario", null,1);
    db= bd.getReadableDatabase();
    String sql="select * from Horario";
    Cursor c;
    String ora;
    ArrayList<String> datos = new ArrayList<String>();

    try {

        c=db.rawQuery(sql,null);
        arrayAdapter= new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1);

        if(c==null||c.getCount()==0) {
            Toast.makeText(getBaseContext(), "No hay eventos disponibles", Toast.LENGTH_LONG).show();
        }

        if(c.moveToFirst()){
            do {
                ora=c.getString(1);
                arrayAdapter.add(ora);

                // agregas los datos al array
                datos.add(ora)
            } while(c.moveToNext());
            listView.setAdapter(arrayAdapter);
        }

    }catch (Exception ex) {
        Toast.makeText(getApplication(), "Error: "+ex.getMessage(), Toast.LENGTH_SHORT).show();
        this.finish();

    }


    int count = listView.getAdapter().getCount();
    for(int i = 0; i <= datos.size(); i = i ++)
    {
        if (i==0){
           TextView TEXTO11=(TextView) findViewById(R.id.t11);
           TEXTO11.setText(datos.get(i));
        }
    }

}