public class MainActivity extends Activity {
TextView statustv = (TextView) findViewById(R.id.status);;
ProgressDialog pd;
String status, url = "http://wvde.state.wv.us/closings/county/monongalia";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
new School().execute();
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
private class School extends AsyncTask<Void, Void, Void> {
#Override
protected void onPreExecute() {
super.onPreExecute();
pd = new ProgressDialog(MainActivity.this);
pd.setTitle("Android Basic JSoup Tutorial");
pd.setMessage("Loading...");
pd.setIndeterminate(false);
pd.show();
}
#Override
protected Void doInBackground(Void... params) {
try {
Document doc = Jsoup.connect(url).get();
Elements table = doc.select("td#content_body");
status = table.select("table").text();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(Void result) {
statustv.setText(status);
pd.dismiss();
}
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_refresh) {
new School().execute();
return true;
}
return super.onOptionsItemSelected(item);
}
}
How can I have new School().execute(); happen oncreate without getting a nullpointer error because right now when oncreate executes it executes new School().execute(); before it even knows what the asynchtask is. How can i have it execute correctly oncreate?
You can post a runnable to the current thread's handler. The runnable starts the AsyncTask.
Here is an easy example of using handler: https://stackoverflow.com/a/1921759/1843698
Official Doc for Handler: http://developer.android.com/reference/android/os/Handler.html
The handler schedule a task (your runnable) in current thread, and your task will be executed later in the same thread as soon as possible, but it will be executed after onCreate() finishes.
Related
I want to show an indeterminate ProgressBar while running the code in my Asynctask, but (if I'm right) because I'm using the .get() function in the MainActivity the UI-thread freezes until the AsyncTask gives response and thus the ProgressBar won't get displayed. How can I make it so that the ProgressBar appears on screen while the UI-thread is waiting for the Asynctask to finish and return some value?
MainActivity
public class MainActivity extends AppCompatActivity {
ProgressBar progressBar;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
progressBar = (ProgressBar) findViewById(R.id.progressBar);
}
public void showSpinner(View view){
CustomAsyncTask customAsyncTask = new CustomAsyncTask(this);
customAsyncTask.setProgressBar(progressBar);
try {
String message = customAsyncTask.execute().get();
} catch (ExecutionException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
Toast.makeText(this,
"Time is up", Toast.LENGTH_LONG).show();
}}
AsyncTask
public class CustomAsyncTask extends android.os.AsyncTask<Void, Void, String> {
Context context;
CustomAsyncTask(Context ctx) {
context = ctx;
}
ProgressBar progressBar;
public void setProgressBar(ProgressBar progressBar) {
this.progressBar = progressBar;
}
#Override
protected String doInBackground(Void... voids) {
SystemClock.sleep(2000);
String message = "hello world";
return message;
}
#Override
protected void onPreExecute() {
progressBar.setVisibility(View.VISIBLE);
}
#Override
protected void onPostExecute(String message) {
progressBar.setVisibility(View.GONE);
}}
Try to run AsyncTask without .get().
You can use interface (see original answer):
Your interface:
public interface OnTaskCompleted{
void onTaskCompleted();
}
Your Activity:
public MainActivity extends AppCompatActivity implements OnTaskCompleted{
//your MainActivity
}
And your AsyncTask:
public class CustomAsyncTask extends android.os.AsyncTask<Void, Void, String> {
private OnTaskCompleted listener;
public CustomAsyncTask(OnTaskCompleted listener){
this.listener=listener;
}
//required methods
protected void onPostExecute(Object o){
//your stuff
listener.onTaskCompleted();
}
}
Another way is add setter for message in MainActivity:
public class MainActivity extends AppCompatActivity {
//...
private String message;
public void setMessage(String message) {
this.message = message;
}
// ...
customAsyncTask.execute();
Then just update message in .onPostExecute() in CustomAsyncTask:
public class CustomAsyncTask extends android.os.AsyncTask<Void, Void, String> {
//...
#Override
protected void onPostExecute(String message) {
progressBar.setVisibility(View.GONE);
MainActivity activity = (MainActivity) context;
activity.setMessage(message);
}
I just updated my project from MvvmCross 3.5.1 stable to 4.2.2. After fixing some other runtime exceptions that popped up after the update, I'm stuck with this one.
I am inflating a layout in an MvxFragment:
_rootView = this.BindingInflate(Resource.Layout.my_layout, null);
This throws a Java.Lang.ClassNotFoundException for Mvx.MvxLinearLayout. With the messages:
Binary XML file line #1: Error inflating class Mvx.MvxLinearLayout
Didn't find class \"Mvx.MvxLinearLayout\" on path: DexPathList[[zip file \"/data/app/com.myapp…
I have already installed the MvvmCross.Binding nuget package.
I the following base activity (which worked fine on 3.5.1):
MvxActionBarActivity
/// <summary>
/// Mvx support for the native ActionBarActivity
/// </summary>
public abstract class MvxActionBarActivity
: MvxActionBarEventSourceActivity
, IMvxAndroidView
{
protected MvxActionBarActivity()
{
BindingContext = new MvxAndroidBindingContext(this, this);
this.AddEventListeners();
}
public object DataContext
{
get { return BindingContext.DataContext; }
set { BindingContext.DataContext = value; }
}
public IMvxViewModel ViewModel
{
get { return DataContext as IMvxViewModel; }
set
{
DataContext = value;
OnViewModelSet();
}
}
public void MvxInternalStartActivityForResult(Intent intent, int requestCode)
{
base.StartActivityForResult(intent, requestCode);
}
public IMvxBindingContext BindingContext { get; set; }
public override void SetContentView(int layoutResId)
{
var view = this.BindingInflate(layoutResId, null);
SetContentView(view);
}
protected virtual void OnViewModelSet()
{
}
MvxActionBarEventSourceActivity
public class MvxActionBarEventSourceActivity : AppCompatActivity
, IMvxEventSourceActivity
{
protected override void OnCreate(Bundle bundle)
{
CreateWillBeCalled.Raise(this, bundle);
base.OnCreate(bundle);
CreateCalled.Raise(this, bundle);
}
protected override void OnDestroy()
{
DestroyCalled.Raise(this);
base.OnDestroy();
}
protected override void OnNewIntent(Intent intent)
{
base.OnNewIntent(intent);
NewIntentCalled.Raise(this, intent);
}
protected override void OnResume()
{
base.OnResume();
ResumeCalled.Raise(this);
}
protected override void OnPause()
{
PauseCalled.Raise(this);
base.OnPause();
}
protected override void OnStart()
{
base.OnStart();
StartCalled.Raise(this);
}
protected override void OnRestart()
{
base.OnRestart();
RestartCalled.Raise(this);
}
protected override void OnStop()
{
StopCalled.Raise(this);
base.OnStop();
}
public override void StartActivityForResult(Intent intent, int requestCode)
{
StartActivityForResultCalled.Raise(this, new MvxStartActivityForResultParameters(intent, requestCode));
base.StartActivityForResult(intent, requestCode);
}
protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
{
ActivityResultCalled.Raise(this, new MvxActivityResultParameters(requestCode, resultCode, data));
base.OnActivityResult(requestCode, resultCode, data);
}
protected override void OnSaveInstanceState(Bundle outState)
{
SaveInstanceStateCalled.Raise(this, outState);
base.OnSaveInstanceState(outState);
}
protected override void Dispose(bool disposing)
{
if (disposing)
{
DisposeCalled.Raise(this);
}
base.Dispose(disposing);
}
public event EventHandler DisposeCalled;
public event EventHandler<MvxValueEventArgs<Bundle>> CreateWillBeCalled;
public event EventHandler<MvxValueEventArgs<Bundle>> CreateCalled;
public event EventHandler DestroyCalled;
public event EventHandler<MvxValueEventArgs<Intent>> NewIntentCalled;
public event EventHandler ResumeCalled;
public event EventHandler PauseCalled;
public event EventHandler StartCalled;
public event EventHandler RestartCalled;
public event EventHandler StopCalled;
public event EventHandler<MvxValueEventArgs<Bundle>> SaveInstanceStateCalled;
public event EventHandler<MvxValueEventArgs<MvxStartActivityForResultParameters>> StartActivityForResultCalled;
public event EventHandler<MvxValueEventArgs<MvxActivityResultParameters>> ActivityResultCalled;
}
Switching my base activity to MvxAppCompatActivity fixed the issue.
I need to update my GUI based on client input. Calling my controller class method, from the background task works. But it can't update the GUI, because it is not the JavaFX application thread..please help.
I tried many of the related Q & A, but I am still confused.
Should I use Platform. runLater or Task ?
Here's my class where I create an instance of controller class
public class FactoryClass {
public static Controller_Gui1 createGUI() {
FXMLLoader fxLoader = new FXMLLoader();
fxLoader.setLocation(MainApp_Gui1.class.getResource("/com/Gui_1.fxml"));
AnchorPane anchorPane = null;
try {
anchorPane = (AnchorPane) fxLoader.load();
} catch (IOException e) {
e.printStackTrace();
}
Controller_Gui1 controller_Gui1 = (Controller_Gui1) fxLoader
.getController();
Scene scene = new Scene(anchorPane);
//System.out.println(scene);
controller_Gui1.setScene(scene);
return controller_Gui1;
}
}
Controller class
#FXML
Button B1 = new Button();
#FXML
public void handleButton1() {
B1.setDisable(true);
}
Application class
public class MainApp_Gui1 extends Application {
Controller_Gui1 cGui;
#Override
public void start(Stage primaryStage) throws Exception {
initScene(primaryStage);
primaryStage.show();
System.out.println("asdasd");
SceneSetting sceneSetting = new SceneSetting();
//handleEvent();
System.out.println("after");
sceneSetting.setSceneAfter();
System.out.println("after2");
}
// creating scene
private void initScene(Stage primaryStage) throws IOException {
primaryStage.setScene(getScene(primaryStage));
}
public Scene getScene(Stage primaryStage) {
Controller_Gui1 cGui;
cGui = FactoryClass.createGUI();
return cGui.getScene();
}
public void ExcessFromOutside() {
Platform.runLater(new Runnable() {
public void run() {
System.out.println(Platform.isFxApplicationThread());
cGui.handleButton1();
}
});
}
public static void main(String[] args) {
launch(args);
}
}
I want to call ExcessFromOutside() method from another thread.
I got a null pointer exception while trying to update the GUI
Here's my application class
public class MainAppGui1 extends Application {
Controller_Gui1 controller_Gui1;
#Override
public void start(Stage primaryStage) throws Exception {
initScene(primaryStage);
primaryStage.show();
}
// creating scene
public void initScene(Stage primaryStage) throws IOException {
FXMLLoader fxLoader = new FXMLLoader();
fxLoader.setLocation(MainApp_Gui1.class.getResource("/com/Gui_1.fxml"));
AnchorPane anchorPane=new AnchorPane();
anchorPane = (AnchorPane) fxLoader.load();
Controller_Gui1 controller_Gui1 = (Controller_Gui1) fxLoader.getController();
Scene scene = new Scene(anchorPane);
primaryStage.setScene(scene);
}
#FXML
public void ExcessFromOutside()
{
Platform.runLater(new Runnable() {
#Override
public void run() {
System.out.println("called atleast");
controller_Gui1.handleButton1();
}
});
}
public static void main(String[] args) {
launch(args);
}
}
and this is the class from where i tried to update the GUI
public class Hudai {
public static void main(String args[]) throws InterruptedException
{
new Thread()
{
public void run()
{
MainAppGui1.main(null);
}
}.start();
Thread.sleep(5000);
MainAppGui1 m = new MainAppGui1();
m.ExcessFromOutside();
}
}
To disable your button in a different thread you can use Task's updateValue.
Task<Boolean> task = new Task<Boolean>() {
#Override
public Boolean call() {
... // The task that this thread needs to do
updateValue(true);
...
return null;
}
};
button.disableProperty().bind(task.valueProperty());
If you want to use a new thread to call a method, which alters the scene graph, the best chance you have is to use Platform.runLater() in it.
//code inside Thread
...
// code to run on the JavaFX Application thread
Platform.runLater(new Runnable() {
#Override
public void run() {
handleButton1();
}
});
...
You should get a NullPointerException when you run this program.
The problem is, the member of MainApp_Gui1
Controller_Gui1 cGui;
never gets a value.
Remove line "Controller_Gui1 cGui;" from this code:
public Scene getScene(Stage primaryStage) {
// Hudai hudai = new Hudai(primaryStage);
// return hudai.getScene();
Controller_Gui1 cGui;
cGui = FactoryClass.createGUI();
return cGui.getScene();
}
I have a Sample WebSocket Program whown below which works fine
When ever the user closes the browser or if there is any excetion Or any disconnect , the onClose Method is
being called
My question is that , Is it possible to know from the program what is the reason for onClose being called ??
Please share your views , Thanks for reading .
public class Html5Servlet extends WebSocketServlet {
private AtomicInteger index = new AtomicInteger();
private static final List<String> tickers = new ArrayList<String>();
static{
tickers.add("ajeesh");
tickers.add("peeyu");
tickers.add("kidillan");
tickers.add("entammo");
}
/**
*
*/
private static final long serialVersionUID = 1L;
public WebSocket doWebSocketConnect(HttpServletRequest req, String resp) {
//System.out.println("doWebSocketConnect");
return new StockTickerSocket();
}
protected String getMyJsonTicker() throws Exception{
return "";
}
public class StockTickerSocket implements WebSocket.OnTextMessage{
private Connection connection;
private Timer timer;
#Override
public void onClose(int arg0, String arg1) {
System.out.println("onClose called!"+arg0);
}
#Override
public void onOpen(Connection connection) {
//System.out.println("onOpen");
this.connection=connection;
this.timer=new Timer();
}
#Override
public void onMessage(String data) {
//System.out.println("onMessage");
if(data.indexOf("disconnect")>=0){
connection.close();
timer.cancel();
}else{
sendMessage();
}
}
public void disconnect() {
System.out.println("disconnect called");
}
public void onDisconnect()
{
System.out.println("onDisconnect called");
}
private void sendMessage() {
if(connection==null||!connection.isOpen()){
//System.out.println("Connection is closed!!");
return;
}
timer.schedule(new TimerTask() {
#Override
public void run() {
try{
//System.out.println("Running task");
connection.sendMessage(getMyJsonTicker());
}
catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}, new Date(),5000);
}
}
}
The signature for onClose is the following ...
#Override
public void onClose(int closeCode, String closeReason) {
System.out.println("onClose called - statusCode = " + closeCode);
System.out.println(" reason = " + closeReason);
}
Where int closeCode is any of the registered Close Status Codes.
And String closeReason is an optional (per protocol spec) close reason message.
I am trying to get my Blackberry application to display a custom modal dialog, and have the opening thread wait until the user closes the dialog screen.
final Screen dialog = new FullScreen();
...// Fields are added to dialog
Application.getApplication().invokeAndWait(new Runnable()
{
public void run()
{
Application.getUiApplication().pushModalScreen(dialog);
}
});
This is throwing an Exception which says "pushModalScreen called by a non-event thread" despite the fact that I am using invokeAndWait to call pushModalScreen from the event thread.
Any ideas about what the real problem is?
Here is the code to duplicate this problem:
package com.test;
import net.rim.device.api.ui.*;
import net.rim.device.api.ui.component.*;
import net.rim.device.api.ui.container.*;
public class Application extends UiApplication {
public static void main(String[] args)
{
new Application();
}
private Application()
{
new Thread()
{
public void run()
{
Application.this.enterEventDispatcher();
}
}.start();
final Screen dialog = new FullScreen();
final ButtonField closeButton = new ButtonField("Close Dialog");
closeButton.setChangeListener(new FieldChangeListener()
{
public void fieldChanged(Field field, int context)
{
Application.getUiApplication().popScreen(dialog);
}
});
dialog.add(closeButton);
Application.getApplication().invokeAndWait(new Runnable()
{
public void run()
{
try
{
Application.getUiApplication().pushModalScreen(dialog);
}
catch (Exception e)
{
// To see the Exception in the debugger
throw new RuntimeException(e.getMessage());
}
}
});
System.exit(0);
}
}
I am using Component Package version 4.5.0.
Building on Max Gontar's observation that the Exception is not thrown when using invokeLater instead of invokeAndWait, the full solution is to implement invokeAndWait correctly out of invokeLater and Java's synchronization methods:
public static void invokeAndWait(final Application application,
final Runnable runnable)
{
final Object syncEvent = new Object();
synchronized(syncEvent)
{
application.invokeLater(new Runnable()
{
public void run()
{
runnable.run();
synchronized(syncEvent)
{
syncEvent.notify();
}
}
});
try
{
syncEvent.wait();
}
catch (InterruptedException e)
{
// This should not happen
throw new RuntimeException(e.getMessage());
}
}
}
Unfortunately, the invokeAndWait method cannot be overridden, so care must be used to call this static version instead.
Seems as though there's a bunch of code in there that's unnecessary.
public class Application extends UiApplication {
public static void main(String[] args)
{
new Application().enterEventDispatcher();
}
private Application()
{
final Screen dialog = new FullScreen();
final ButtonField closeButton = new ButtonField("Close Dialog");
closeButton.setChangeListener(new FieldChangeListener()
{
public void fieldChanged(Field field, int context)
{
Application.getUiApplication().popScreen(dialog);
}
});
dialog.add(closeButton);
// this call will block the current event thread
pushModalScreen(dialog);
System.exit(0);
}
}
Use this:
UiApplication.getUiApplication().invokeAndWait(new Runnable() {
public void run() {
pushScreen(new MyScreen());
}
});