Friday, October 16, 2009

ListView and ListActivity

A ListView is a View that shows items in a vertically scrolling list. The items are acquired from a ListAdapter.

In this exercise, I will show how to implement a ListView using ListActivity. The main activity (AndroidListView) call the ListActivity(AndroidListActivity) by startActivityForResult. AndroidListActivity have a ListView only, the selected item will be passed back to AndroidListView by means of Bundle.



_ Create a new Android Application named AndroidListView

- Modify main.xml to have a Button to start the ListActivity with ListView, and have a TextView to show the result from ListActivity.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/hello"
/>
<Button
android:id="@+id/selectCountryButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="Select Country"
/>
<TextView
android:id="@+id/myCountry"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
/>
</LinearLayout>


- Modify AndroidListView.java
package com.exercise.AndroidListView;

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

public class AndroidListView extends Activity {

TextView MyCountry;

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

MyCountry = (TextView)findViewById(R.id.myCountry);
Button SelectCountryButton = (Button)findViewById(R.id.selectCountryButton);
SelectCountryButton.setOnClickListener(SelectCountryButtonOnClickListener);
}

private Button.OnClickListener SelectCountryButtonOnClickListener =
new Button.OnClickListener()
{
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent intent = new Intent();
intent.setClass(AndroidListView.this, AndroidListActivity.class);

startActivityForResult(intent, 0);
}
};

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
// TODO Auto-generated method stub
super.onActivityResult(requestCode, resultCode, data);
if (requestCode==0)
{
switch (resultCode)
{ case RESULT_OK:
MyCountry.setText(data.getStringExtra("country"));
break;
case RESULT_CANCELED:
break;

}

}
}


}


- Create AndroidListActivity extends ListActivity

Right click com.exercise.AndroidListView, the package In the Project Windows on the left. Select New > Class >

Click Browser beside Superclass, select ListActivity. (May be you have to clear the content inside "Choose a type" box to make it appear in the "Matching items" list.

Type AndroidListActivity in the Name



Click Finish

- Modify AndroidListActivity
package com.exercise.AndroidListView;

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

public class AndroidListActivity extends ListActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);

setListAdapter(new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, COUNTRIES));
getListView().setTextFilterEnabled(true);
}

static final String[] COUNTRIES = new String[] {
"Afghanistan", "Albania", "Algeria", "American Samoa",
"Andorra", "Angola", "Anguilla", "Antarctica",
"Antigua and Barbuda", "Argentina", "Armenia", "Aruba",
"Australia", "Austria", "Azerbaijan", "Bahrain",
"Bangladesh", "Barbados", "Belarus", "Belgium", "Belize",
"Benin", "Bermuda", "Bhutan", "Bolivia",
"Bosnia and Herzegovina", "Botswana", "Bouvet Island",
"Brazil", "British Indian Ocean Territory",
"British Virgin Islands", "Brunei", "Bulgaria",
"Burkina Faso", "Burundi", "Cote d'Ivoire", "Cambodia",
"Cameroon", "Canada", "Cape Verde", "Cayman Islands",
"Central African Republic", "Chad", "Chile", "China",
"Christmas Island", "Cocos (Keeling) Islands", "Colombia",
"Comoros", "Congo", "Cook Islands", "Costa Rica", "Croatia",
"Cuba", "Cyprus", "Czech Republic",
"Democratic Republic of the Congo", "Denmark", "Djibouti",
"Dominica", "Dominican Republic", "East Timor", "Ecuador",
"Egypt", "El Salvador", "Equatorial Guinea", "Eritrea",
"Estonia", "Ethiopia", "Faeroe Islands", "Falkland Islands",
"Fiji", "Finland", "Former Yugoslav Republic of Macedonia",
"France", "French Guiana", "French Polynesia",
"French Southern Territories", "Gabon", "Georgia", "Germany",
"Ghana", "Gibraltar", "Greece", "Greenland", "Grenada",
"Guadeloupe", "Guam", "Guatemala", "Guinea", "Guinea-Bissau",
"Guyana", "Haiti", "Heard Island and McDonald Islands",
"Honduras", "Hong Kong", "Hungary", "Iceland", "India",
"Indonesia", "Iran", "Iraq", "Ireland", "Israel", "Italy",
"Jamaica", "Japan", "Jordan", "Kazakhstan", "Kenya", "Kiribati",
"Kuwait", "Kyrgyzstan", "Laos", "Latvia", "Lebanon", "Lesotho",
"Liberia", "Libya", "Liechtenstein", "Lithuania", "Luxembourg",
"Macau", "Madagascar", "Malawi", "Malaysia", "Maldives", "Mali",
"Malta", "Marshall Islands", "Martinique", "Mauritania",
"Mauritius", "Mayotte", "Mexico", "Micronesia", "Moldova",
"Monaco", "Mongolia", "Montserrat", "Morocco", "Mozambique",
"Myanmar", "Namibia", "Nauru", "Nepal", "Netherlands",
"Netherlands Antilles", "New Caledonia", "New Zealand",
"Nicaragua", "Niger", "Nigeria", "Niue", "Norfolk Island",
"North Korea", "Northern Marianas", "Norway", "Oman", "Pakistan",
"Palau", "Panama", "Papua New Guinea", "Paraguay", "Peru",
"Philippines", "Pitcairn Islands", "Poland", "Portugal",
"Puerto Rico", "Qatar", "Reunion", "Romania", "Russia", "Rwanda",
"Sqo Tome and Principe", "Saint Helena", "Saint Kitts and Nevis",
"Saint Lucia", "Saint Pierre and Miquelon",
"Saint Vincent and the Grenadines", "Samoa", "San Marino",
"Saudi Arabia", "Senegal", "Seychelles", "Sierra Leone",
"Singapore", "Slovakia", "Slovenia", "Solomon Islands", "Somalia",
"South Africa", "South Georgia and the South Sandwich Islands",
"South Korea", "Spain", "Sri Lanka", "Sudan", "Suriname",
"Svalbard and Jan Mayen", "Swaziland", "Sweden", "Switzerland",
"Syria", "Taiwan", "Tajikistan", "Tanzania", "Thailand",
"The Bahamas", "The Gambia", "Togo", "Tokelau", "Tonga",
"Trinidad and Tobago", "Tunisia", "Turkey", "Turkmenistan",
"Turks and Caicos Islands", "Tuvalu", "Virgin Islands", "Uganda",
"Ukraine", "United Arab Emirates", "United Kingdom",
"United States", "United States Minor Outlying Islands",
"Uruguay", "Uzbekistan", "Vanuatu", "Vatican City", "Venezuela",
"Vietnam", "Wallis and Futuna", "Western Sahara", "Yemen",
"Yugoslavia", "Zambia", "Zimbabwe"
};

@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
// TODO Auto-generated method stub
super.onListItemClick(l, v, position, id);

Intent intent = new Intent();
Bundle bundle = new Bundle();

bundle.putString("country", l.getItemAtPosition(position).toString());
intent.putExtras(bundle);
setResult(RESULT_OK, intent);
finish();
}

}


Notice that we don't need to load a layout (at least, not in this case, because we're using the whole screen for our list). Instead, we just call setListAdapter() (which automatically adds a ListView to the ListActivity), and provide it with an ArrayAdapter that binds a simple_list_item_1 layout item to each entry in the COUNTRIES array (added next). The next line of code adds a text filter to the ListView, so that when the user begins typing, the list will filter the entire view to display only the items that match the entry.

- Modify AndroidMainfest.xml to include the AndroidListActivity.
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.exercise.AndroidListView"
android:versionCode="1"
android:versionName="1.0">
<application android:icon="@drawable/icon" android:label="@string/app_name">
<activity android:name=".AndroidListView"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".AndroidListActivity"></activity>
</application>
<uses-sdk android:minSdkVersion="3" />

</manifest>


Actually, it's same as Google example Hello, ListView, with some extra; such as how the inter-action between main activity and the ListActivity.

Download the files.

7 comments:

edward said...

hi thaxs for the tutorial

Q) I have 3tab and listview on each tab
i want new activity on every row

listview: http://www.androidpeople.com/android-listview-example/
tab: http://www.androidpeople.com/android-tabhost-tutorial-part-1/

I am doing a project for my class, onclick(ing) student name it will show a form with student pic. and their details, i just want
to know how to do the onclick for the row.

thnk u and rply ASAP....URGENT*...

id: edwardpark.1997@gmail.com

Android Er said...

onListItemClick(ListView l, View v, int position, long id) will be called when any item in the list is selected/clicked. Where position is the the index of the item clicked.

Refer ListActivity and onListItemClick()

edward said...

thanks, but i want to start a new activity from listview, is it possible to start a new activity(textview) on seleting row, And i want, separate form(textview) for each row...??

Android Er said...

Yes, you can start another activity in onListItemClick() using startActivity, and pass data using Intent & Bundle.

But passing image/bitmap between activity is very inefficiency. It's suggested to keep image in files, and pass the uri, or keep image in the second activity, just pass the info to select which image.

edward said...

again thxs...i have on more question on bluetooth function... but untill then i'll give it a try c ya tk care

navas ar said...

I have create a list view activity. I want to able to open another list view activity When I click each list item.I don't know Where to put the code. Please correct it.



public class Mainpage extends Activity {
String[] names = {"apple","orange","mango"};
ListView lisview;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.mainpage);
lisview = (ListView) findViewById(R.id.listView);
ArrayAdapter adapter = new ArrayAdapter(Mainpage.this, android.R.layout.simple_list_item_1, names);
lisview.setAdapter(adapter);
lisview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
public String[] Apple;
@Override
public void onItemClick(AdapterView adapterView, View view, int i, long l)
{
Toast.makeText(getBaseContext(),""+names[i],Toast.LENGTH_SHORT).show();
Intent intent=new Intent(getApplicationContext(),Apple);
intent.putExtra("apple",apple);
startActivity(intent);

Andr.oid Eric said...

hello navas ar,

basically your code is correct. What problem is it?