Develop Reference

Widget issue: Exiting the main app resets the static variables in the widget

I have a widget with a button. In my app widget (TestWidget.java) I have a private static boolean variable (buttonClicked) initialized to false.
When I click on the button the boolean buttonClicked is set to true. I have an updatePeriodMillis set to the minimum 30min (1800000ms).
First onUpdate comes: buttonClicked value is true. As expected.
Then I stop my main app. The following onUpdates shows buttonClicked value as false.
launch --> 06-10 10:55:56.365 4186-4186/com.narb.testwidget I/TESTWID: update setButtonClicked false
1st onUpdate after button click --> 06-10 10:56:11.685 4186-4186/com.narb.testwidget I/TESTWID: setButtonClicked true
onUpdate after main app exit --> I/TESTWID: update setButtonClicked false
Why is that?
App widget - TestWidget
public class TestWidget extends AppWidgetProvider {
private static RemoteViews views;
private static boolean buttonClicked = false;
static void updateAppWidget(Context context, AppWidgetManager appWidgetManager,
int appWidgetId) {
appWidgetManager.updateAppWidget(appWidgetId, views);
}
#Override
public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
// Get all ids
ComponentName thisWidget = new ComponentName(context,
TestWidget.class);
int[] allWidgetIds = appWidgetManager.getAppWidgetIds(thisWidget);
Log.i("TESTWID", "update setButtonClicked "+buttonClicked);
views = new RemoteViews(context.getPackageName(), R.layout.test_widget);
views.setOnClickPendingIntent(R.id.wid_btn_tst, setButton(context));
for (int appWidgetId : appWidgetIds) {
updateAppWidget(context, appWidgetManager, appWidgetId);
}
}
public static void setButtonClicked(boolean b){
buttonClicked = b;
Log.i("TESTWID", "setButtonClicked "+buttonClicked);
}
public static PendingIntent setButton(Context context) {
Intent intent = new Intent();
intent.setAction("TEST");
return PendingIntent.getBroadcast(context, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
}
public static void pushWidgetUpdate(Context context, RemoteViews remoteViews) {
ComponentName myWidget = new ComponentName(context, TestWidget.class);
AppWidgetManager manager = AppWidgetManager.getInstance(context);
manager.updateAppWidget(myWidget, remoteViews);
}
}
Button code - TestWidgetReceiver
public class TestWidgetReceiver extends BroadcastReceiver{
private static boolean isButtonON = false;
#Override
public void onReceive(Context context, Intent intent) {
if(intent.getAction().equals("TEST")){
updateWidgetButton(context, 2);
}
}
private void updateWidgetButton(Context context, int index) {
RemoteViews remoteViews = new RemoteViews(context.getPackageName(), R.layout.test_widget);
if(index == 2) {
if(isButtonON) {
remoteViews.setTextViewText(R.id.wid_btn_tst, "Test Off");
isButtonON = false;
}
else{
remoteViews.setTextViewText(R.id.wid_btn_tst, "Test On");
isButtonON = true;
TestWidget.setButtonClicked(isButtonON);
}
//REMEMBER TO ALWAYS REFRESH YOUR BUTTON CLICK LISTENERS!!!
remoteViews.setOnClickPendingIntent(R.id.wid_btn_tst, TestWidget.setButton(context));
}
TestWidget.pushWidgetUpdate(context.getApplicationContext(), remoteViews);
}
}
Manifest
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="Test"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<receiver android:name=".TestWidget">
<intent-filter>
<action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
</intent-filter>
<meta-data
android:name="android.appwidget.provider"
android:resource="#xml/test_widget_info" />
</receiver>
<receiver
android:name=".TestWidgetReceiver"
android:label="widgetBroadcastReceiver" >
<intent-filter>
<action android:name="TEST" />
</intent-filter>
<meta-data
android:name="android.appwidget.provider"
android:resource="#xml/test_widget_info" />
</receiver>
</application>

In my app widget (TestWidget.java) I have a private static boolean variable (buttonClicked) initialized to false
static variables are a cache, at best.
Then I stop my main app.
I do not know exactly what you mean by that. My guess is that you mean that you remove a task associated with your app from the overview screen.
The following onUpdates shows buttonClicked value as false. Why is that?
If by "stop my main app", you do something like I outlined, you will have terminated your process. At a later point, such as when you click your app widget's button, Android will start a fresh process for you, at which point your static field, at which point your static field will be its default value.
I would have thought that widgets have their own memory copy as they continue to run even if the main app has exited?
No. The views associated with your app widget will exist, in the home screen. That does not include your TestWidget code, which is not part of the home screen.
I'm considering dropping this approach to do an alarmManager with a low refresh time (10 secs).
First, that's not possible on Android 5.1 and above, as it substantially drains the battery. Second, it does not guarantee that your process will stay around.
static variables are a cache, at best. Any app, including those with an app widget, need to store important data somewhere else: SharedPreferences, SQLite database, some other sort of file, a server, etc.

If you force stop the app or the system decides to stop it due to low memory, all classes are dropped from the memory and all static variables are lost. In this case, you should either persist your data to the DB or SharedPreferences or similar or rethink the approach itself. Is it really necessary to do it the way you're doing here?

Run app widget - Could not identify launch activity

In AndroidStudio i create a new android project an create a app widget and choose option for configuration activity. AndroidStudio generates now the provider-info xml, the declerations in manifest xml an the both java classes. One activity, one widget provider.
This should be runnable but i get error: Could not identify launch activity: Default Activity not found. Error while Launching activity. The launch field also shows a red cross.
I dont understand why because there is no default activity. The configuration activity should start when the widget provider start working. To do so there is a intent-filter for the activitiy with android.appwidget.action.APPWIDGET_CONFIGURE.
I add also categroy in intent-filter LAUNCHER and DEFAULT. In provider and in activity. But still get the error message.
If I choose "Nothing" in launch configuration and I run the app it brings only many error messages: Waiting for application to come online: com.example.desktop_win10.myapplication | com.example.desktop_win10.myapplication.test
But the widget isnt installed and doesnt run. What doing Im wrong? I try out Intellij and AndroidStudio.
Manifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.desktop_win10.myapplication" >
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:supportsRtl="true"
android:theme="#style/AppTheme" >
<receiver android:name=".NewAppWidget" >
<intent-filter>
<action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
</intent-filter>
<meta-data
android:name="android.appwidget.provider"
android:resource="#xml/new_app_widget_info" />
</receiver>
<activity android:name=".NewAppWidgetConfigureActivity" >
<intent-filter>
<action android:name="android.appwidget.action.APPWIDGET_CONFIGURE" />
</intent-filter>
</activity>
</application>
</manifest>
widget_info.xml:
<?xml version="1.0" encoding="utf-8"?>
<appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android"
android:minWidth="40dp"
android:minHeight="40dp"
android:updatePeriodMillis="86400000"
android:previewImage="#drawable/example_appwidget_preview"
android:initialLayout="#layout/new_app_widget"
android:configure="com.example.desktop_win10.myapplication.NewAppWidgetConfigureActivity"
android:resizeMode="horizontal|vertical"
android:widgetCategory="home_screen"
android:initialKeyguardLayout="#layout/new_app_widget">
</appwidget-provider>
And there are the two Java classes.
EDIT1:
Now I add category LAUNCHER and action MAIN:
<activity android:name=".NewAppWidgetConfigureActivity" >
<intent-filter>
<action android:name="android.appwidget.action.APPWIDGET_CONFIGURE" />
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
If I start the debugger sometimes the widget ist in the widget store and sometimes not.
I also see that in the generated java activity class is a finish method called:
// If this activity was started with an intent without an app widget ID, finish with an error.
if (mAppWidgetId == AppWidgetManager.INVALID_APPWIDGET_ID) {
finish();
return;
}
But it also doesnt work if I delete thid. I dont unterstand why a the default google example not work.
Here are the java classes:
Activity:
package com.example.desktop_win10.myapplication;
import android.app.Activity;
import android.appwidget.AppWidgetManager;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
/**
* The configuration screen for the {#link NewAppWidget NewAppWidget} AppWidget.
*/
public class NewAppWidgetConfigureActivity extends Activity {
int mAppWidgetId = AppWidgetManager.INVALID_APPWIDGET_ID;
EditText mAppWidgetText;
private static final String PREFS_NAME = "com.example.desktop_win10.myapplication.NewAppWidget";
private static final String PREF_PREFIX_KEY = "appwidget_";
public NewAppWidgetConfigureActivity() {
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 the user presses the back button.
setResult(RESULT_CANCELED);
setContentView(R.layout.new_app_widget_configure);
mAppWidgetText = (EditText)findViewById(R.id.appwidget_text);
findViewById(R.id.add_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 this activity was started with an intent without an app widget ID, finish with an error.
if (mAppWidgetId == AppWidgetManager.INVALID_APPWIDGET_ID) {
finish();
return;
}
mAppWidgetText.setText(loadTitlePref(NewAppWidgetConfigureActivity.this, mAppWidgetId));
}
View.OnClickListener mOnClickListener = new View.OnClickListener() {
public void onClick(View v) {
final Context context = NewAppWidgetConfigureActivity.this;
// When the button is clicked, store the string locally
String widgetText = mAppWidgetText.getText().toString();
saveTitlePref(context,mAppWidgetId,widgetText);
// It is the responsibility of the configuration activity to update the app widget
AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context);
NewAppWidget.updateAppWidget(context, appWidgetManager, mAppWidgetId);
// 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.apply();
}
// 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 titleValue = prefs.getString(PREF_PREFIX_KEY + appWidgetId, null);
if (titleValue != null) {
return titleValue;
} else {
return context.getString(R.string.appwidget_text);
}
}
static void deleteTitlePref(Context context, int appWidgetId) {
SharedPreferences.Editor prefs = context.getSharedPreferences(PREFS_NAME, 0).edit();
prefs.remove(PREF_PREFIX_KEY + appWidgetId);
prefs.apply();
}
}
And Provider:
package com.example.desktop_win10.myapplication;
import android.appwidget.AppWidgetManager;
import android.appwidget.AppWidgetProvider;
import android.content.Context;
import android.widget.RemoteViews;
/**
* Implementation of App Widget functionality.
* App Widget Configuration implemented in {#link NewAppWidgetConfigureActivity NewAppWidgetConfigureActivity}
*/
public class NewAppWidget extends AppWidgetProvider {
#Override
public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
// There may be multiple widgets active, so update all of them
for (int appWidgetId : appWidgetIds) {
updateAppWidget(context, appWidgetManager, appWidgetId);
}
}
#Override
public void onDeleted(Context context, int[] appWidgetIds) {
// When the user deletes the widget, delete the preference associated with it.
for (int appWidgetId : appWidgetIds) {
NewAppWidgetConfigureActivity.deleteTitlePref(context, appWidgetId);
}
}
#Override
public void onEnabled(Context context) {
// Enter relevant functionality for when the first widget is created
}
#Override
public void onDisabled(Context context) {
// Enter relevant functionality for when the last widget is disabled
}
static void updateAppWidget(Context context, AppWidgetManager appWidgetManager,
int appWidgetId) {
CharSequence widgetText = NewAppWidgetConfigureActivity.loadTitlePref(context, appWidgetId);
// Construct the RemoteViews object
RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.new_app_widget);
views.setTextViewText(R.id.appwidget_text, widgetText);
// Instruct the widget manager to update the widget
appWidgetManager.updateAppWidget(appWidgetId, views);
}
}

Did you add:
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER" />
?
As I know, without it android won't know which activity to launch as the main activity.

Android Widget Service Class to bind Collection not being Called By Provider

Please bear with me because I am new to Android development.
I am building a widget that opens up a Configuration Activity upon placement on the home screen. When I am finished configuration and have pressed "done", the widget provider (onUpdate) is supposed to call the widget service class to bind a list of drawables to a gridview. However, the service class is not being called and the gridview is coming up empty. Any help on this is appreciated, code is included below:
*Note: i have a main.xml that has the gridview in it and another xml that has the template (imageView and textView) the gridview cell.
Manifest:
<service android:name=".WidgetService" android:permission="android.permission.BIND_REMOTEVIEWS" android:exported="false" />
<receiver android:name=".WidgetProvider" android:label="#string/app_name">
<intent-filter>
<action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
</intent-filter>
<meta-data android:name="android.appwidget.provider" android:resource="#xml/button_widget_provider" />
</receiver>
Provider:
public class WidgetProvider extends AppWidgetProvider {
public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
for (int i=0; i < appWidgetIds.length; i++){
Intent intent = new Intent(context, WidgetService.class);
intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetIds[i]);
intent.setData(Uri.parse(intent.toUri(Intent.URI_INTENT_SCHEME)));
RemoteViews remoteViews = new RemoteViews(context.getPackageName(), R.layout.main);
remoteViews.setRemoteAdapter(appWidgetIds[i], R.id.gridview, intent);
appWidgetManager.updateAppWidget(appWidgetIds[i], remoteViews);
}
super.onUpdate(context, appWidgetManager, appWidgetIds);
}
......(omitted code)}
Service:
public class WidgetService extends RemoteViewsService {
#Override
public RemoteViewsFactory onGetViewFactory(Intent intent){
return new VZRemoteViewsFactory(this.getApplicationContext(), intent);
}
}
class VZRemoteViewsFactory implements RemoteViewsService.RemoteViewsFactory{
public VZRemoteViewsFactory(Context context, Intent intent){
thisContext = context;
appWidgetId = intent.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID);
}
public void onCreate(){
// code to add drawables to list here
}
public RemoteViews getViewAt(int position){
RemoteViews remoteView = new RemoteViews(thisContext.getPackageName(), R.layout.vzwidget_item);
// setting the image view resource this way for now just for testing
remoteView.setImageViewResource(R.id.launcher_icon, R.drawable.vzicon);
remoteView.setTextViewText(R.id.textview, "test");
return remoteView;
}
.....(omitted code)}
Thank You!

From my experience (and looking at my own just written widget) - OnUpdate is called right when the configuration activity is launched, and after you publish the results from this activity, the following intent action is given to the appWidgetProvider - android.appwidget.action.APPWIDGET_UPDATE_OPTIONS (tested on jellybean).
This might not be the most proper way to handle this, but this is how I am handling this -
when the configuration activity publishes the result - I start up my remote view service and start sending views with the proper widgetid.

Android widget using a config activity wont update

I am making an Android widget to display real time transportation information based on bus stop numbers. It displays the next 3 bus arrivals for the stop number and has a button where the user can refresh the data. That was working ok until I tried adding my widget configuration activity.
Now when you select the widget, a configuration screen is opened where you enter your bus stop number. Once you do that the widget is added to the home screen, but it will not execute the method to gather data and the refresh button will not work for that either. I have not been able to figure out why.
WidgetConfig
public class WidgetConfig extends Activity implements OnClickListener{
EditText info;
AppWidgetManager awm;
Context c;
int awID;
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.widget_config);
Button b = (Button)findViewById(R.id.bWidgetConfig);
b.setOnClickListener(this);
c = WidgetConfig.this;
//getting info about the widget that launched this activity
Intent i = getIntent();
Bundle extras = i.getExtras();
if (extras != null){
awID = extras.getInt(AppWidgetManager.EXTRA_APPWIDGET_ID,
AppWidgetManager.INVALID_APPWIDGET_ID);
}else{
finish();
}
awm = AppWidgetManager.getInstance(c);
}
public void onClick(View v) {
// TODO Auto-generated method stub
info = (EditText)findViewById(R.id.etWidgetConfig);
String e = info.getText().toString();
RemoteViews views = new RemoteViews(c.getPackageName(), R.layout.widget_layout);
views.setTextViewText(R.id.tvStopNum, e);
Intent in = new Intent(c, WidgetConfig.class);
PendingIntent pi = PendingIntent.getActivity(c, 0, in, PendingIntent.FLAG_UPDATE_CURRENT);
views.setOnClickPendingIntent(R.id.tvStopNum, pi);
awm.updateAppWidget(awID, views);
Intent result = new Intent();
result.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, awID);
setResult(RESULT_OK, result);
finish();
}
AppWidgetProvider
public class MyWidgetProvider extends AppWidgetProvider {
#Override
public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds){
RemoteViews remoteViews = new RemoteViews(context.getPackageName(), R.layout.widget_layout);
// Create a new intent that will target this class
Intent intent = new Intent(context, MyWidgetProvider.class);
intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetIds[0]);
intent.setAction("update");
// Create a new PendingIntent which will be run whenever the refresh button is pressed
// This PendingIntent will run the intent we just created before this
PendingIntent pi = PendingIntent.getBroadcast(context, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
remoteViews.setOnClickPendingIntent(R.id.button1, pi);
// Manually run the AsyncTask to initially populate the 5 question fields
new RTPIinformation().execute(context);
appWidgetManager.updateAppWidget(appWidgetIds, remoteViews);
}
// This method is called when it receives an Intent. In particular, it will
// receive an intent whenever the refresh button is clicked
#Override
public void onReceive(Context context, Intent intent){
super.onReceive(context, intent);
if (intent.getAction().equals("update")){
new RTPIinformation().execute(context);
}
}
class RTPIinformation extends AsyncTask<Context, Void, List<RealtimeData>>{
.
.
.
}
Manifest
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.ruben.dublin.bus.widget"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="15" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<application
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".WidgetConfig"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.appwidget.action.APPWIDGET_CONFIGURE" />
</intent-filter>
</activity>
<receiver
android:name=".MyWidgetProvider"
android:label="#string/app_name">
<intent-filter>
<action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
</intent-filter>
<meta-data android:name="android.appwidget.provider"
android:resource="#xml/widget_info" />
</receiver>
</application>
Any help would be greatly appreciated

Widget has a weird bahaviour

I have developed an application that makes use of a widget. The widget could be added in the homescreen and used as a button. I have recently downgraded the version to <uses-sdk android:minSdkVersion="7" /> and no errors were spotted. However, now when i reinstall the, the widget is not responsive. In addition when I try to install the app on another phone running android 4.0.3, widget is not available anywhere, so i cannot even add it to the homescreen. Here is my code for the widget:
public class MyWidget extends AppWidgetProvider {
#Override
public void onUpdate(Context c, AppWidgetManager appWidgetManager,int[] appWidgetIds) {
final int N = appWidgetIds.length;
//for each of the instances of the widget
for (int i=0; i<N; i++) {
int appWidgetId = appWidgetIds[i];
RemoteViews views = new RemoteViews(c.getPackageName(), R.layout.widget_layout);
Intent fireDialog = new Intent(c,Execute.class);
PendingIntent pendingIntent = PendingIntent.getActivity(c, 0, fireDialog, 0);
views.setOnClickPendingIntent(R.id.myButton, pendingIntent); //when the button is clicked, an activity is launched
appWidgetManager.updateAppWidget(appWidgetId, views);
}
}
#Override
public void onReceive(Context c, Intent intent)
{
final String action=intent.getAction();
if(AppWidgetManager.ACTION_APPWIDGET_DELETED.equals(action)){
final int appWidgetId=intent.getExtras().getInt(AppWidgetManager.EXTRA_APPWIDGET_ID,AppWidgetManager.INVALID_APPWIDGET_ID);
if(appWidgetId!=AppWidgetManager.INVALID_APPWIDGET_ID){
this.onDeleted(c,new int[]{appWidgetId});
}
}else{
super.onReceive(c, intent);
}
}
}
Here is the manifest.xml:
<application>
<receiver android:name=".myButton"
android:icon="#drawable/icon"
android:label="myWidget">
<intent-filter>
<action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
</intent-filter>
<meta-data android:name="android.appwidget.provider"
android:resource="#xml/my_xml" />
</receiver>
</application>