Can't get BasicViews5 tutorial to work

wolfenr · November 1st, 2012, 05:06 AM

Hi, I'm wondering if anyone else has the same issue in that I can't get the BasicViews5 tutorial to work which appears on pages 191 - 199.

I've written the code as it appears in the book and tried it and also downloaded the source code and both fail.

I have 2 problems

In the early part of building up the example I should be able to click on one or several items in the list and a tick box appear against the chosen item. It doesn't
Also the additions at the end of the tutorial causes the emulator to crash on start up and TBH I can't say that I've got to grips with LogCat yet so can't track down the error.

Here's my code:-

Code:

package net.example.basicviews5;

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

public class BasicViews5 extends ListActivity {

	String[] presidents;

	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);

		setContentView(R.layout.activity_basic_views5);

		ListView lstView = getListView();

		// lstView.setChoiceMode(ListView.CHOICE_MODE_NONE);
		// lstView.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
		lstView.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
		lstView.setTextFilterEnabled(true);

		presidents = getResources().getStringArray(R.array.presidents_array);

		setListAdapter(new ArrayAdapter<String>(this,
				android.R.layout.simple_list_item_checked, presidents));
	}

	public void onListItemClick(ListView parent, View v, int position, long id) {
		Toast.makeText(this, "You have selected " + presidents[position],
				Toast.LENGTH_SHORT).show();
	}

	public void onClick(View view) {
		ListView lstView = getListView();

		String itemsSelected = "Selected items: \n";
		for (int i = 0; i < lstView.getCount(); i++) {
			if (lstView.isItemChecked(i)) {
				itemsSelected += lstView.getItemAtPosition(i) + "\n";
			}
		}
		Toast.makeText(this, itemsSelected, Toast.LENGTH_LONG).show();
	}

}

And the layout file...

Code:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <Button
        android:id="@+id/btn"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Show selected items"
        android:onClick="onClick" />

</LinearLayout>

wolfenr · December 28th, 2013, 08:10 AM

OK, after some time off I've started going through all the examples in the book again. Don't know what I was doing last time around but notice that my problem lies in the layout file in that I'd failed to include the <ListView> in the layout so,
a) The Java code is unchanged
b) The layout file should look like this (note match_parent and fill_parent in width settings are interchangeable) :

Code:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <Button
        android:id="@+id/btn"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="onClick"
        android:text="Show selected items" />

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


</LinearLayout>

And my problem is now RESOLVED!
Thanks for your interest.