app widget code snippets
satya - Friday, September 11, 2009 2:50:05 PM
appwidget_provider.xml
<appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android"
android:minWidth="60dp"
android:minHeight="30dp"
android:updatePeriodMillis="86400000"
android:initialLayout="@layout/appwidget_provider"
android:configure="com.....ExampleAppWidgetConfigure"
>
</appwidget-provider>
This is where you define the nature of your widget, how it shows on the screen.
satya - Friday, September 11, 2009 2:51:34 PM
layout/appwidget_provider.xml
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/appwidget_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#ff000000"
/>
This is the layout. just a text box. simple enough.
satya - Friday, September 11, 2009 2:55:04 PM
Here is the configuration view
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/appwidget_configure_instructions"
/>
<EditText
android:id="@+id/appwidget_prefix"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
<Button
android:id="@+id/save_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@android:string/ok"
/>
</LinearLayout>
This has three controls
This text will be shown before your date edit box OK button
satya - Friday, September 11, 2009 2:58:53 PM
Declaring your widget as a broadcast receiver in the manifest file
<receiver android:name=".appwidget.ExampleAppWidgetProvider">
<meta-data android:name="android.appwidget.provider"
android:resource="@xml/appwidget_provider" />
<intent-filter>
<action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
</intent-filter>
</receiver>
satya - Friday, September 11, 2009 3:15:17 PM
Here is the provider
public class ExampleAppWidgetProvider extends AppWidgetProvider {
public void onUpdate(Context context,
AppWidgetManager appWidgetManager,
int[] appWidgetIds)
{
final int N = appWidgetIds.length;
for (int i=0; i<N; i++)
{
int appWidgetId = appWidgetIds[i];
String titlePrefix =
ExampleAppWidgetConfigure.loadTitlePref(context, appWidgetId);
updateAppWidget(context, appWidgetManager, appWidgetId, titlePrefix);
}
}
public void onDeleted(Context context, int[] appWidgetIds) {
final int N = appWidgetIds.length;
for (int i=0; i<N; i++) {
ExampleAppWidgetConfigure.deleteTitlePref(context, appWidgetIds[i]);
}
}
public void onEnabled(Context context)
{
// When the first widget is created, register for
// the TIMEZONE_CHANGED and TIME_CHANGED
// broadcasts. We don't want to be listening for these
// if nobody has our widget active.
// This setting is sticky across reboots, but that doesn't
// matter, because this will
// be called after boot if there is a widget
// instance for this provider.
PackageManager pm = context.getPackageManager();
pm.setComponentEnabledSetting(
new ComponentName("com.example.android.apis",
".appwidget.ExampleBroadcastReceiver"),
PackageManager.COMPONENT_ENABLED_STATE_ENABLED,
PackageManager.DONT_KILL_APP);
}
public void onDisabled(Context context) {
// When the first widget is created,
// stop listening for the TIMEZONE_CHANGED and
// TIME_CHANGED broadcasts.
Class clazz = ExampleBroadcastReceiver.class;
PackageManager pm = context.getPackageManager();
pm.setComponentEnabledSetting(
new ComponentName("com.example.android.apis",
".appwidget.ExampleBroadcastReceiver"),
PackageManager.COMPONENT_ENABLED_STATE_ENABLED,
PackageManager.DONT_KILL_APP);
}
static void updateAppWidget(Context context,
AppWidgetManager appWidgetManager,
int appWidgetId, String titlePrefix)
{
// Getting the string this way allows the string to be localized.
// The format
// string is filled in using java.util.Formatter-style format strings.
CharSequence text = context.getString(R.string.appwidget_text_format,
ExampleAppWidgetConfigure.loadTitlePref(context, appWidgetId),
"0x" + Long.toHexString(SystemClock.elapsedRealtime()));
// Construct the RemoteViews object.
// It takes the package name (in our case, it's our
// package, but it needs this because on the other
// side it's the widget host inflating
// the layout from our package).
RemoteViews views = new RemoteViews(context.getPackageName(),
R.layout.appwidget_provider);
views.setTextViewText(R.id.appwidget_text, text);
// Tell the widget manager
appWidgetManager.updateAppWidget(appWidgetId, views);
}
}
satya - Friday, September 11, 2009 3:22:27 PM
understanding pendingintent
satya - Friday, September 11, 2009 3:30:40 PM
The configurator code
public class ExampleAppWidgetConfigure extends Activity {
static final String TAG = "ExampleAppWidgetConfigure";
private static final String PREFS_NAME
= "com.example.android.apis.appwidget.ExampleAppWidgetProvider";
private static final String PREF_PREFIX_KEY = "prefix_";
int mAppWidgetId = AppWidgetManager.INVALID_APPWIDGET_ID;
EditText mAppWidgetPrefix;
public ExampleAppWidgetConfigure() {
super();
}
@Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
// Set the result to CANCELED. This will cause the widget host to cancel
// out of the widget placement if they press the back button.
setResult(RESULT_CANCELED);
// Set the view layout resource to use.
setContentView(R.layout.appwidget_configure);
// Find the EditText
mAppWidgetPrefix = (EditText)findViewById(R.id.appwidget_prefix);
// Bind the action for the save button.
findViewById(R.id.save_button).setOnClickListener(mOnClickListener);
// Find the widget id from the intent.
Intent intent = getIntent();
Bundle extras = intent.getExtras();
if (extras != null) {
mAppWidgetId = extras.getInt(
AppWidgetManager.EXTRA_APPWIDGET_ID,
AppWidgetManager.INVALID_APPWIDGET_ID);
}
// If they gave us an intent without the widget id, just bail.
if (mAppWidgetId == AppWidgetManager.INVALID_APPWIDGET_ID) {
finish();
}
mAppWidgetPrefix.setText(loadTitlePref(ExampleAppWidgetConfigure.this, mAppWidgetId));
}
View.OnClickListener mOnClickListener = new View.OnClickListener() {
public void onClick(View v) {
// When the button is clicked, save the string in our prefs and return that they
// clicked OK.
saveTitlePref(ExampleAppWidgetConfigure.this, mAppWidgetId,
mAppWidgetPrefix.getText().toString());
// Make sure we pass back the original appWidgetId
Intent resultValue = new Intent();
resultValue.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, mAppWidgetId);
setResult(RESULT_OK, resultValue);
finish();
}
};
// Write the prefix to the SharedPreferences object for this widget
static void saveTitlePref(Context context, int appWidgetId, String text) {
SharedPreferences.Editor prefs = context.getSharedPreferences(PREFS_NAME, 0).edit();
prefs.putString(PREF_PREFIX_KEY + appWidgetId, text);
prefs.commit();
}
// Read the prefix from the SharedPreferences object for this widget.
// If there is no preference saved, get the default from a resource
static String loadTitlePref(Context context, int appWidgetId) {
SharedPreferences prefs = context.getSharedPreferences(PREFS_NAME, 0);
String prefix = prefs.getString(PREF_PREFIX_KEY, null);
if (prefix != null) {
return prefix;
} else {
return context.getString(R.string.appwidget_prefix_default);
}
}
static void deleteTitlePref(Context context, int appWidgetId) {
}
static void loadAllTitlePrefs(Context context, ArrayList<Integer> appWidgetIds,
ArrayList<String> texts) {
}
}
satya - Saturday, September 12, 2009 8:17:12 AM
A code sample from Jeff Sharkey
/**
* Define a simple widget that shows the Wiktionary "Word of the day." To build
* an update we spawn a background {@link Service} to perform the API queries.
*/
public class WordWidget extends AppWidgetProvider {
@Override
public void onUpdate(Context context, AppWidgetManager appWidgetManager,
int[] appWidgetIds) {
// To prevent any ANR timeouts, we perform the update in a service
context.startService(new Intent(context, UpdateService.class));
}
public static class UpdateService extends Service {
@Override
public void onStart(Intent intent, int startId) {
// Build the widget update for today
RemoteViews updateViews = buildUpdate(this);
// Push update for this widget to the home screen
ComponentName thisWidget = new ComponentName(this, WordWidget.class);
AppWidgetManager manager = AppWidgetManager.getInstance(this);
manager.updateAppWidget(thisWidget, updateViews);
}
/**
* Build a widget update to show the current Wiktionary
* "Word of the day." Will block until the online API returns.
*/
public RemoteViews buildUpdate(Context context) {
// Pick out month names from resources
Resources res = context.getResources();
String[] monthNames = res.getStringArray(R.array.month_names);
// Find current month and day
Time today = new Time();
today.setToNow();
// Build today's page title, like "Wiktionary:Word of the day/March 21"
String pageName = res.getString(R.string.template_wotd_title,
monthNames[today.month], today.monthDay);
RemoteViews updateViews = null;
String pageContent = "";
try {
// Try querying the Wiktionary API for today's word
SimpleWikiHelper.prepareUserAgent(context);
pageContent = SimpleWikiHelper.getPageContent(pageName, false);
} catch (ApiException e) {
Log.e("WordWidget", "Couldn't contact API", e);
} catch (ParseException e) {
Log.e("WordWidget", "Couldn't parse API response", e);
}
// Use a regular expression to parse out the word and its definition
Pattern pattern = Pattern.compile(SimpleWikiHelper.WORD_OF_DAY_REGEX);
Matcher matcher = pattern.matcher(pageContent);
if (matcher.find()) {
// Build an update that holds the updated widget contents
updateViews = new RemoteViews(context.getPackageName(), R.layout.widget_word);
String wordTitle = matcher.group(1);
updateViews.setTextViewText(R.id.word_title, wordTitle);
updateViews.setTextViewText(R.id.word_type, matcher.group(2));
updateViews.setTextViewText(R.id.definition, matcher.group(3).trim());
// When user clicks on widget, launch to Wiktionary definition page
String definePage = res.getString(R.string.template_define_url,
Uri.encode(wordTitle));
Intent defineIntent = new Intent(Intent.ACTION_VIEW, Uri.parse(definePage));
PendingIntent pendingIntent = PendingIntent.getActivity(context,
0 /* no requestCode */, defineIntent, 0 /* no flags */);
updateViews.setOnClickPendingIntent(R.id.widget, pendingIntent);
} else {
// Didn't find word of day, so show error message
updateViews = new RemoteViews(context.getPackageName(), R.layout.widget_message);
CharSequence errorMessage = context.getText(R.string.widget_error);
updateViews.setTextViewText(R.id.message, errorMessage);
}
return updateViews;
}
@Override
public IBinder onBind(Intent intent) {
// We don't need to bind to this service
return null;
}
}
}
satya - Saturday, September 12, 2009 8:18:09 AM
This code is taken from the following blog of Jeff Sharkey