Question

I am trying to create 5 buttons in my main activity and am trying to put new activities in them.

In the fifth button, I am having a problem with listView.

In the below code, am I missing anything required for the listView(View v) method to work properly?

Here is my code:

listActivity.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >

<ListView
    android:id="@+id/listView1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" >
</ListView>
   
</LinearLayout>

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >

<TextView
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="@string/hello" />

<Button
    android:id="@+id/button1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:onClick="newActivity"
    android:text="Yeni Aktivite" />

<Button
    android:id="@+id/button2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:onClick="toast"
    android:text="Toast" />

<Button
    android:id="@+id/button3"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:onClick="web"
    android:text="Web" />

<Button
    android:id="@+id/button4"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:onClick="preferences"
    android:text="Preferences" />

<Button
    android:id="@+id/button5"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:onClick="listVieww"
    android:text="ListView" />

  </LinearLayout>

Main activity

package com.uygulamalar.odev;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

public class OdevKarmaActivity extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);        
    }

    public void newActivity(View v) {
        Intent intent = new Intent(getApplicationContext(), NewActivity.class);
        startActivity(intent);
    }

    public void toast(View v) {
        Toast toast=Toast.makeText(getApplicationContext(), "vazzupp", 9999);
        toast.show();
    }

    public void listVieww(View v) {
        ListView listView1;
        String jedigiller[] = {"pelin","figen","aylin","gizem"};
    
        listView1=(ListView) findViewById(R.id.listView1);
        listView1.setAdapter(new
                ArrayAdapter<String>(this,android.R.layout.simple_list_item_1 , jedigiller));
    }
}

When run, the code forces the Android emulator to close.

I am suspecting that the issue is related to the listView(View v) method, did I miss anything when using it?

Answer 1

You are attempting to reference a ListView found in listActivity.xml, while you have set your content view to main.xml.

Either copy the ListView over to main.xml, or start a new Activity in listVieww() that displays the list, and uses setContentView(R.layout.listActivity);