I have an AsyncTask that I call from the main thread, and I wish to pop a dialog out when it completes. Other than putting the dialog code in OnPostExecute(), is there a way where I can put it in the main activity code instead?
Thanks.
You may use an interface for that. It is simple and forward:
1- create a new interface:
public interface IShowPopup {
public void showPopup(String title, string message);
}
2 - implement that interface in your activity:
... MyActivity extends Activity implements IShowPopup {
...
public void showPopup(String title, String message) {
// create a DialogAlert here.
AlertDialog.Builder builder = new AlertDialog.Builder(MyActivity.this);
builder.setMessage(message);
builder.setTitle(R.string.app_license_title);
AlertDialog dialog = builder.create();
// show dialog.
dialog.show();
}
...
}
3 - in your task you keep an instance of the activity:
...MyTask extends AsyncTask<...> {
private IShowPopup iShowPopup ;
// get the interface from constructor.
public MyTask(IShowPopup isp) {
this.iShowPopup = isp;
}
4 - use the interface in your onPostExecute:
#Override
public void onPostExecute(??) {
// get some title and message.
iShowPopup.showPopup(title, message);
}
That should be it!
Related
I am creating some kind of custom reporting with cucumber with custom listener/formatter. but I am unable to add some data from test context to my report.
I know we share data/state between steps using cucumber-picocontainer, but my question is how can I access test context data from the custom listener/formatter that i am writing?
Cucumber-Java : 5.2.0
Update: Adding more details. is there a way i can use use context object in the custom listener/plugin. i would like to context.setFailMessage(""); from the custom listener.
Thanks,
Vikas
In order to create custom reporting in cucumber, you have to follow the below steps.
Step 1: Implement ConcurrentEventListener interface
public class DesktopStepDisplayer implements ConcurrentEventListener
Step 2: Add the implementation in EventHandler as show below
private EventHandler<TestStepStarted> eventHandler = new EventHandler<TestStepStarted>()
{
public void receive(TestStepStarted event)
{
if(event.getTestStep() instanceof PickleStepTestStep)
{
String message = ((PickleStepTestStep)event.getTestStep()).getStep().getText();
}
};
public void setEventPublisher(EventPublisher publisher) {
publisher.registerHandlerFor(TestStepStarted.class, eventHandler);
}
Step 3: Set the event publisher
public void setEventPublisher(EventPublisher publisher) {
publisher.registerHandlerFor(TestStepStarted.class, eventHandler);
}
Entire Script:
public class DesktopStepDisplayer implements ConcurrentEventListener {
private EventHandler<TestStepStarted> eventHandler = new EventHandler<TestStepStarted>()
{
public void receive(TestStepStarted event)
{
if(event.getTestStep() instanceof PickleStepTestStep)
{
String message = ((PickleStepTestStep)event.getTestStep()).getStep().getText();
}
};
public void setEventPublisher(EventPublisher publisher) {
publisher.registerHandlerFor(TestStepStarted.class, eventHandler);
}
}
I have a test project with Room database. Using Asynctask I can successfully insert an object with some test data into the database. I'm trying to learn RxJava and replace Asynctask with RxJava's observer, but it doesn't work. I have read alot of documentation and watched tutorials, but I don't think I quite get it. Here's the relevant code:
Here I set my Room object with the data from my List:
for(ObjectForArray item: listToDatabase) {
myRoomEntity.setName( item.getName() );
Log.d( "TAG", myRoomEntity.getName() );
}
Then I try to use RxJava Observable to insert data into the database. This was originally and successfully done using Asynctask:
Observable<MyRoomEntity> myRX = Observable
.just(myRoomEntity)
.subscribeOn( Schedulers.io() )
.observeOn( AndroidSchedulers.mainThread() );
myRX.subscribe( new Observer<MyRoomEntity>() {
#Override
public void onSubscribe(Disposable d) {
Log.d("TAG ONSUBSCRIBE", d.toString());
try {
myViewModel.insertDatabase( myRoomEntity );
Log.d( "TAG", "Populating database Success" );
}catch(Error error) {
Log.d( "TAG", error.toString() );
}
}
The OnNext, OnError and OnComplete are empty.
When I run the project it crashes with the error:
Cannot access database on the main thread since it may potentially lock the UI for a long period of time.
I'm obviously using RxJava wrong since the point is to do asynchronous tasks away from the main thread.
i have use RX java in replace of Asyntask as it has been deprecated in android 9
there are multiple replacements that android provides like Executors, threads, Listenable Futures , Coroutines 🔥, so you are looking how to implement this with rxjava and how RX Java java helps your to migrate just add these dependencies first in gradle
implementation "io.reactivex.rxjava2:rxjava:2.2.20"
implementation "io.reactivex.rxjava2:rxandroid:2.1.1"
once you import lets start working with RX java i will let you know where you can put background task, pre execute, on post execute like asynctask
lets start codding with Rx java first , i have comment in the method that will help you to put the code
Observable.fromCallable(new Callable<Boolean>() {
#Override
public Boolean call() throws Exception {
/// here is your background task
return true;
}
}).subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread())
.subscribe(new Observer<Boolean>() {
#Override
public void onSubscribe(Disposable d) {
//// pre execute here is my progress dialog
showProgressDialog(getString(R.string.scanning));
}
#Override
public void onNext(Boolean aBoolean) {
//// here is on sucess you can do anystuff here like
if (aBoolean){
/// if its value true you can go ahead with this
}
}
#Override
public void onError(Throwable e) {
/// this helps you to go if there is any error show dialog whatever you wants here
Log.e("error of kind",e.getMessage() );
}
#Override
public void onComplete() {
/// when your task done means post execute
}
});
once its done lets start working with implementation
Observable.fromCallable(new Callable<Boolean>() {
#Override
public Boolean call() throws Exception {
/// here is your background task
uribitmap = getScannedBitmap(original, points);
uri = Utils.getUri(getActivity(), uribitmap);
scanner.onScanFinish(uri);
return true;
}
}).subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread())
.subscribe(new Observer<Boolean>() {
#Override
public void onSubscribe(Disposable d) {
//// pre execute here is my progress dialog
showProgressDialog(getString(R.string.scanning));
}
#Override
public void onNext(Boolean aBoolean) {
//// here is on sucess you can do anystuff here like
if (aBoolean){
/// if its value true you can go ahead with this
}
}
#Override
public void onError(Throwable e) {
/// this helps you to go if there is any error show dialog whatever you wants here
Log.e("error of kind",e.getMessage() );
}
#Override
public void onComplete() {
/// when your task done means post execute
uribitmap.recycle();
dismissDialog();
}
});
now i will do this with executors :
/// pre execute you can trigger to progress dialog
showProgressDialog(getString(R.string.scanning));
ExecutorService executors = Executors.newSingleThreadExecutor();
executors.execute(new Runnable() {
#Override
public void run() {
//// do background heavy task here
final Bitmap uribitmap = getScannedBitmap(original, points);
uri = Utils.getUri(getActivity(), uribitmap);
scanner.onScanFinish(uri);
new Handler(Looper.getMainLooper()).post(new Runnable() {
#Override
public void run() {
//// Ui thread work like
uribitmap.recycle();
dismissDialog();
}
});
}
});
You are getting this error because you are trying to insert an Object on the main (UI) thread.
You should do something like this:
Observable.fromCallable(() -> myViewModel.insertDatabase( myRoomEntity ))
.subscribeOn( Schedulers.io() )
.observeOn( AndroidSchedulers.mainThread() );
And then use an Observer to subscribe to the Observable.
Please try restructuring your code like this:
Completable.fromAction(() -> myViewModel.insertDatabase(myRoomEntity))
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(() -> Log.d("TAG", "Populating database Success"),
throwable -> Log.d("TAG", throwable.toString()))
Considerations:
If your myRoomEntity is not available before this whole construct gets subscribed, make sure you use defer http://reactivex.io/documentation/operators/defer.html
Your subscribe section handlers are operating on "main", that's why you were receiving a crash.
If possible, avoid unnecessary just calls
I read much about the JavaFX GUI Model, Plattform->RunLater and Threads, but I still do not figure out how to get this right. I had a JavaFX GUI which on a button click executed a process and updated a Progress Bar and Label. This was running well with Threading and Platform, but I had to Change this to an Observer Model.
I invoke a Progress Tracker in a Singleton Model, which gets updated by the class executing the process and is Observable. I implemented an Observer as well which should update the two UI Elements.
GUI Controller with Button Event
private void createKeyPressed(ActionEvent event) {
// Make Progressbar visible
pbKeyProgress.visibleProperty().set(true);
if (!Check.keyFileExistant() || cbKeyOverwrite.selectedProperty().get()) {
ProgressTracker.getTracker().addObserver(new ProgressObserver(pbKeyProgress, lblKeyProgress));
Creator.createKey(cbKeyLength.getValue());
} else {
}
}
Progress Observer
public class ProgressObserver implements Observer {
private final ProgressBar progressBar;
private final Label statusLabel;
public ProgressObserver(ProgressBar progressBar, Label statusLabel) {
this.progressBar = progressBar;
this.statusLabel = statusLabel;
}
#Override
public void update(Observable o, Object o1) {
Platform.runLater(() -> {
System.out.println("Tracker set to "+ProgressTracker.getProgress() + " " + ProgressTracker.getStatus());
progressBar.setProgress(ProgressTracker.getProgress());
statusLabel.setText(ProgressTracker.getStatus());
});
}
}
Progress Tracker
public synchronized void setTracker(int currentStep, String currentStatus) {
checkInstance();
instance.step = currentStep;
instance.status = currentStatus;
instance.notifyObservers();
System.out.println(instance.countObservers());
}
Creator
public static void createKey(String length) {
Task<Void> task;
task = new Task<Void>() {
#Override
public Void call() throws Exception {
initTracker(0,"Start");
doStuff();
ProgressTracker.getTracker().setTracker(1,"First");
doStuff();
ProgressTracker.getTracker().setTracker(2,"Second");
// and so on
return null;
}
};
new Thread(task)
.start();
}
The Print within the ProgressTracker gets executed. However, if I add a print within the update of the Observer nothing will be printed. If I check within the Progresstracker, the Observer Count is 1.
Why does the Observer not get notified or execute anything, even if the Notify is called? Did I get the Threading and Execution Modell wrong?
The Progress Bar and the Label will also stay on their initial values.
Don't reinvent the wheel. The JavaFX Properties Pattern is a ready-made implementation of the Observable pattern: there is no need to implement it yourself. Additionally, Task already defines methods for updating various properties, which can be called from any thread but will schedule the actual updates on the FX Application Thread. See updateProgress() and updateMessage(), for example.
So you can do, for example:
public static Task<Void> createKey(String length) {
Task<Void> task;
task = new Task<Void>() {
final int totalSteps = ... ;
#Override
public Void call() throws Exception {
updateProgress(0, totalSteps);
updateMessage("Start");
doStuff();
updateProgress(1, totalSteps);
updateMessage("First");
doStuff();
updateProgress(2, totalSteps);
updateMessage("Second");
// and so on
return null;
}
};
new Thread(task)
.start();
return task ;
}
and
private void createKeyPressed(ActionEvent event) {
// Make Progressbar visible
pbKeyProgress.visibleProperty().set(true);
if (!Check.keyFileExistant() || cbKeyOverwrite.selectedProperty().get()) {
Task<Void> task = Creator.createKey(cbKeyLength.getValue());
pbKeyProgress.progressProperty().bind(task.progressProperty());
lblKeyProgress.textProperty().bind(task.messageProperty());
} else {
}
}
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Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question.
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I've been trying to get Application Level Pause and Resume similar to an activity's onPause and onResume. I know there's no API that has this functionality.
I try to follow this post: http://curioustechizen.blogspot.com/2012/12/android-application-level-pause-and.html
But I've had no luck so far.
Has anyone been able to achieve this? What paradigm did you use?
Let me know if you need me to paste some code into this question.
Thanks for the help
Another solution to the problem would be to just keep track of the count of onStart() and onStop() calls from every activity. Example:
First, create a class to hold the counts:
public class ActiveActivitiesTracker {
private static int sActiveActivities = 0;
public static void activityStarted()
{
if( sActiveActivities == 0 )
{
// TODO: Here is presumably "application level" resume
}
sActiveActivities++;
}
public static void activityStopped()
{
sActiveActivities--;
if( sActiveActivities == 0 )
{
// TODO: Here is presumably "application level" pause
}
}
}
Then in every activity, simply call the activityStarted() and activityStopped() methods:
#Override
public void onStart() {
super.onStart();
ActiveActivitiesTracker.activityStarted();
}
#Override
public void onStop() {
super.onStop();
ActiveActivitiesTracker.activityStopped();
}
I had the same problem. My aim was to lock the App, if the user abandons it. A simple aim, which i thought would be easy to implement. But all the solutions I found were way to complex. So I came to a simple solution: A time based lock.
Basically it works like this:
Start countdown to lock app in onPause
Stop countdown in onResume
If onResume is not called in time, change to locked
Therefor I created a small little class:
public class ApplicationLock {
private static final String TAG = ApplicationLock.class.getSimpleName();
private static final int LOCK_TIME = 1000; //lock after a second
private static boolean lock = true; //default is locked
private static Handler handler = new Handler();
private static Runnable runnable = new Runnable() {
#Override
public void run() {
lock = true;
Log.i("ActivityTracker", "App locked");
}
};
public static boolean activityStarted()
{
handler.removeCallbacks(runnable);
if(lock)
{
Log.i(TAG, "App resumed - LOCKED");
return true;
}else{
Log.i(TAG, "App resumed - NOT LOCKED");
return false;
}
}
public static void activityStopped()
{
handler.postDelayed(runnable, LOCK_TIME);
Log.i(TAG, "App paused - Starting countdown");
}
Just call activityStopped() in your activities onPause() and activityStarted() in onResume(). Check the result of activityStarted(). If it returns true, lock your app. If the orientation of the app is changed, onResume will be called very quickly after onPause, so the app will not lock.
This solution might not fit every scenario, but in my case it was the best solution. Additionally you can change the countdown, to increase the user experience (The user pressed a wrong button and returns to the app in a few seconds, no need to lock the app). Hope this is useful to someone else.
I have done something very similar to this in an app which used a service that provided GPS functions by several activities. The idea was to only have the service there when one of the activities that used it is visible, and not there when none are visible. In your case, every activity would hook into a service, and you will know when the entire application was paused or resumed by hooking into the service's onCreate() and onDestroy() methods.
Here is a stripped-down example:
Components needed (these could probably be placed into a utility class if you want to reuse them, or I just had them for each activity class):
private boolean mAppActiveServiceBound = false;
private AppActiveService mAppActiveService = null;
private ServiceConnection mAppActiveConnection = new ServiceConnection() {
public void onServiceConnected( ComponentName className, IBinder service ) {
mAppActiveService = ( (AppActiveService.AppActiveBinder) service ).getService();
}
public void onServiceDisconnected( ComponentName className ) {
mAppActiveService = null;
}
};
Then in your onStart() and onStop() methods for each activity:
#Override
public void onStart() {
super.onStart();
mAppActiveServiceBound = bindService( new Intent( this, AppActiveService.class ), mAppActiveConnection, Context.BIND_AUTO_CREATE );
}
#Override
public void onStop() {
super.onStop();
if( mAppActiveServiceBound ) {
unbindService( mAppActiveConnection );
mAppActiveServiceBound = false;
}
}
And finally, the service itself:
public class AppActiveService extends Service {
// Receives interactions from clients:
private final IBinder mBinder = new AppActiveBinder();
/**
* Provides a handle to the bound service.
*/
public class AppActiveBinder extends Binder {
AppActiveService getService() {
return AppActiveService.this;
}
}
#Override
public void onCreate(){
// TODO: Here is presumably "application level" resume
}
#Override
public void onDestroy(){
// TODO: Here is presumably "application level" pause
}
}
I am working with j2me using lwuit I have one problem is that
when I am startApp() inside midlet I first set Display.init(this)
and run application lwuit work good but when I am using Form inside startApp() event in midlet it good work but in this form actionevent I am call new form and in this new form
I put one back command when I pressed it it does not move on main midlet
please help how know lwuit use
import javax.microedition.MIDlet;
import some lwuit UILibrary
public class mainMiddlet extends MIDlet implement ActionListner
{
public mainMiddlet(){
try{
Display.init(this);
//somthing is here
form=new Form();
form.addActionListener(this);
}catch(Exception e){}
}
public void actionperformed(ActionEven ae){
//here i call new form
//in action event of this form
new form().show();
}
//here some middlet default method
}
public class newForm extends Form {
//in this form I am put one command back and when i am pressed it
// I call mainMiddlet but it throw error internal application java.lang.nullpointer
// can I back on mainmiddlet from on form to another form
// my main problem is I am not move on mainmiddlet for exit middlet because destoryall()
// is method of middlet
}
Its just simple. You can call the show() method inside next form back command. For example,
MainMidlet.java
// create the midlet and write inside of the midlet
final Form form = new Form();
form.addCommand(new Command("Next") {
public void actionPerformed(ActionEvent evt) {
new NewForm(form).show();
}
});
NewForm.java
// create the NewForm class and write inside of the class
public NewForm(final Form form) {
// Constructor
addCommand(new Command("Back") {
public void actionPerformed(ActionEvent evt) {
form.show();
}
});
}