Android and Lists
Here is the tutorial for how to make ListView using ListView Activity in android.
Let's Discuss About what we can achieve using ListView Activity in android.
You can directly use the "ListView" in your layout as any other UI component. In case your Activity is primary showing a list you can extend the activity "ListActivity" which simplifies the handling of a "ListView". "ListActivity" extends "Activity" and provides simplified handling of lists. For example you have a predefine method if someone clicks on a list element.
"ListActivity" contains a "ListAdapter" which is responsible for managing the data. This adapter must be set in the onCreate() method of your Activity via the method setListAdapter().
If the user select in the list a list entry the method onListItemClick() will be called. This method allows to access the selected element.
Android provides already some default layouts which you can use in your Adapter, e.g. "android.R.layout.simple_list_item1". In case you don't want to use one of the pre-defined layouts your own layout must have an element with the id "@android:id/list" which is the ListView. You can also use a view with the id "@android:id/empty". This view is displayed if the list is empty. For example you could display here an error message.
ListViews and performance:
Showing a big dataset must be with efficiency implemented on a mobile device. Therefore the ListView solitary creates views (widget) if needed and attach them to the view hierarchy. The default Adapter implementation for a ListView will recycle views, e.g. if a row is not displayed anymore it will be recycled and only its content will change. If you implement your own adapter for a view you also should do this to avoid performance problems.
Let's Begin
For the simple ListView we don't require to put <ListView/> in activity so here is the code for main Activity.
public class SimpleListActivityActivity extends ListActivity {
/** Called when the activity is first created. */
/** When we are using ListActivity we don't need to find the ListView in xml by Id*/
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//setContentView(R.layout.main);
this.setListAdapter(new ArrayAdapter<String>(SimpleListActivityActivity.this, android.R.layout.simple_list_item_1, COUNTRIES));
}
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) {
super.onListItemClick(l, v, position, id);
Object o=this.getListAdapter().getItem(position);
String name=o.toString();
Toast.makeText(SimpleListActivityActivity.this, name, 2000).show();
}
}
here is the screen which you will get from Android AVD:
For any thing missing and if you use eclipse than press ctrl+shift+O it will automatic import require java classes from android.
