Figured this out, and its so simple, by passing the context as an argument to my AsyncTask constructor I then have access to all the stuff the UI thread has. In my onPostExecute(..) method all I did is this:
Intent i=new Intent(ctx,SillyActivity.class); ctx.startActivity(i); Where ctx is a context object. I understand now that you can't call methods from the UI thread in the AsyncTask. On Mar 7, 1:08 am, John Wesonga <[email protected]> wrote: > I figured something out which I thought would work, within my > LoginTask class I created an object which was of the parent activity: > > Test101 mParentActivity; > > and then: > > protected void onPostExecute(String result) { > > Intent i=new Intent(ctx,SillyActivity.class); > mParentActivity.startActivity(i); > > } > > An error is thrown: > > 03-07 01:04:50.259: ERROR/AndroidRuntime(801): Uncaught handler: > thread main exiting due to uncaught exception > 03-07 01:04:50.319: ERROR/AndroidRuntime(801): > java.lang.NullPointerException > 03-07 01:04:50.319: ERROR/AndroidRuntime(801): at > org.tutorial.test101.tasks.LoginTask.onPostExecute(LoginTask.java:46) > 03-07 01:04:50.319: ERROR/AndroidRuntime(801): at > org.tutorial.test101.tasks.LoginTask.onPostExecute(LoginTask.java:1) > 03-07 01:04:50.319: ERROR/AndroidRuntime(801): at > android.os.AsyncTask.finish(AsyncTask.java:416) > 03-07 01:04:50.319: ERROR/AndroidRuntime(801): at > android.os.AsyncTask.access$300(AsyncTask.java:127) > 03-07 01:04:50.319: ERROR/AndroidRuntime(801): at > android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:428) > 03-07 01:04:50.319: ERROR/AndroidRuntime(801): at > android.os.Handler.dispatchMessage(Handler.java:99) > 03-07 01:04:50.319: ERROR/AndroidRuntime(801): at > android.os.Looper.loop(Looper.java:123) > 03-07 01:04:50.319: ERROR/AndroidRuntime(801): at > android.app.ActivityThread.main(ActivityThread.java:3948) > 03-07 01:04:50.319: ERROR/AndroidRuntime(801): at > java.lang.reflect.Method.invokeNative(Native Method) > 03-07 01:04:50.319: ERROR/AndroidRuntime(801): at > java.lang.reflect.Method.invoke(Method.java:521) > 03-07 01:04:50.319: ERROR/AndroidRuntime(801): at > com.android.internal.os.ZygoteInit > $MethodAndArgsCaller.run(ZygoteInit.java:782) > 03-07 01:04:50.319: ERROR/AndroidRuntime(801): at > com.android.internal.os.ZygoteInit.main(ZygoteInit.java:540) > 03-07 01:04:50.319: ERROR/AndroidRuntime(801): at > dalvik.system.NativeStart.main(Native Method) > > Stuck again it seems.. > > On Mar 6, 10:57 pm, John Wesonga <[email protected]> wrote: > > > > > I just modified my onPostExecute(...) method: > > > protected void onPostExecute(String result) { > > > Log.i("LOGGER", "Done..."); > > pDialog.dismiss(); > > if(result=="success"){ > > Toast.makeText(ctx, "complete", > > Toast.LENGTH_LONG).show(); > > Intent i=new > > Intent(ctx,SillyActivity.class); > > startActivity(i); > > }else{ > > Toast.makeText(ctx, "fail", > > Toast.LENGTH_LONG).show(); > > } > > > super.onPostExecute(result); > > } > > > ctx is my context > > I noticed that I can't call the startActivity(Intent i) method within > > the AsyncTask, how else would I start an activity from here? > > > On Mar 6, 10:13 pm, Romain Guy <[email protected]> wrote: > > > > onPostExecute() is invoked on the UI thread so you can use this method > > > to start an Activity. It's pretty much what it's for. > > > > On Fri, Mar 5, 2010 at 6:29 AM, John Wesonga <[email protected]> > > > wrote: > > > > I have a simple app and I'm using the AsyncTask to test out a > > > > background process, for clearness purposes I've opted to put my > > > > AsyncTask in a separate class rather than in an inner class, which > > > > where my problems begin, this is my AsyncTask > > > > > package org.tutorial.test101.tasks; > > > > > import android.app.ProgressDialog; > > > > import android.content.Context; > > > > import android.os.AsyncTask; > > > > import android.util.Log; > > > > > public class LoginTask extends AsyncTask<String, String, String> { > > > > > Context ctx; > > > > ProgressDialog pDialog; > > > > > public LoginTask(Context context){ > > > > super(); > > > > this.ctx=context; > > > > } > > > > �...@override > > > > protected String doInBackground(String... params) { > > > > Log.i("LOGGER", "Starting..."); > > > > try{ > > > > Thread.sleep(8000); > > > > }catch(InterruptedException e){ > > > > > } > > > > return null; > > > > } > > > > > �...@override > > > > protected void onPostExecute(String result) { > > > > > Log.i("LOGGER", "Done..."); > > > > pDialog.dismiss(); > > > > // > > > > super.onPostExecute(result); > > > > } > > > > > �...@override > > > > protected void onPreExecute() { > > > > pDialog=new ProgressDialog(ctx); > > > > pDialog.setTitle("Login"); > > > > pDialog.setMessage("doing stuff.."); > > > > pDialog.show(); > > > > } > > > > > } > > > > > What I'd like is that once the task is complete, I do something in the > > > > UI thread may be start another activity or even display a Toast saying > > > > activity complete. I know I can't start a new Activity in the > > > > onPostExecute() so I need to start it in the UI thread any idea how I > > > > can do this? This is my Activity that starts the AsyncTask > > > > > package org.tutorial.test101.activities; > > > > > import org.tutorial.test101.tasks.LoginTask; > > > > > import android.app.Activity; > > > > import android.app.Dialog; > > > > import android.content.Context; > > > > import android.os.AsyncTask; > > > > import android.os.Bundle; > > > > import android.util.Log; > > > > import android.view.View; > > > > import android.view.View.OnClickListener; > > > > import android.widget.Button; > > > > > public class Test101 extends Activity{ > > > > private Button btnLogin; > > > > private LoginTask mLoginTask; > > > > private Context context=this; > > > > /** Called when the activity is first created. */ > > > > �...@override > > > > public void onCreate(Bundle savedInstanceState) { > > > > super.onCreate(savedInstanceState); > > > > setContentView(R.layout.main); > > > > btnLogin=(Button)findViewById(R.id.btnLogin); > > > > btnLogin.setOnClickListener(new OnClickListener(){ > > > > > public void onClick(View v) { > > > > if(mLoginTask==null){ > > > > mLoginTask=new > > > > LoginTask(context); > > > > mLoginTask.execute(null); > > > > } > > > > > } > > > > > }); > > > > } > > > > > } > > > > > -- > > > > You received this message because you are subscribed to the Google > > > > Groups "Android Developers" group. > > > > To post to this group, send email to [email protected] > > > > To unsubscribe from this group, send email to > > > > [email protected] > > > > For more options, visit this group at > > > >http://groups.google.com/group/android-developers?hl=en > > > > -- > > > Romain Guy > > > Android framework engineer > > > [email protected] > > > > Note: please don't send private questions to me, as I don't have time > > > to provide private support. All such questions should be posted on > > > public forums, where I and others can see and answer them -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
