Question

Well, I’ve got an application that crashes on load up because of a setContentView line.
Now before you ask, its when I comment out the setContentView line on line 15 or so that I get a working app. But the moment I place it in, it errors. Now this is using 2.1-update1 android.

Java:

package com.clark.listview;

import android.app.ListActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;

public class listview extends ListActivity {
    /** Called when the activity is first created. */
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        //setContentView(R.layout.main);
        // Create an array of Strings, that will be put to our ListActivity
        String[] names = new String[] { "Linux", "Windows7", "Eclipse", "Suse",
                "Ubuntu", "Solaris", "Android", "iPhone", "ClarkPhone" };
        // Use your own layout and point the adapter to the UI elements which
        // contains the label
        this.setListAdapter(new ArrayAdapter<String>(this, R.layout.rowlayout,
                R.id.label, names));
    }

    @Override
    protected void onListItemClick(ListView l, View v, int position, long id) {
        super.onListItemClick(l, v, position, id);
        // Get the item that was clicked
        Object o = this.getListAdapter().getItem(position);
        String keyword = o.toString();
        Toast.makeText(this, "You selected: " + keyword, Toast.LENGTH_LONG)
                .show();
        if (keyword.startsWith("Windows7") || keyword.startsWith("iPhone")
                || keyword.startsWith("Solaris")) {
            launchTest();
        }


    }
    protected void launchTest() {
        Intent i = new Intent(this, home.class);
        startActivity(i);
    }

}

XML:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout android:id="@+id/main"
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content"
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:cacheColorHint="#00000000"
    android:background="@drawable/bg">
</LinearLayout>

Answer 1

If your Activity is extending the ListActivity class then ensure that your main layout file must contain a ListView element as given below.

<ListView android:id="@android:id/list" android:layout_height="wrap_content"
android:layout_width="match_parent" />

your application is crashing because you are setting an adapter to ListView which is indeed not exist in your layout file.

See the documentation : http://developer.android.com/reference/android/app/ListActivity.html