CN1 Library - No code fires in runOnUiThread - codenameone

Question

No code is firing in runOnUiThread in the native implementation. Codes before runOnUiThread does fire. I am sure I am not doing something right.
I created the CodenameOne Library like this
package com.uithread.test;
import com.codename1.system.NativeInterface;
public interface UIThreadNative extends NativeInterface {
public void runNativeCode();
}
package com.uithread.test;
import com.codename1.system.NativeLookup;
import com.codename1.ui.Dialog;
public class UIThreadManager {
private static UIThreadNative uithreadNative;
public UIThreadManager() {
if (uithreadNative == null) {
uithreadNative = (UIThreadNative) NativeLookup.create(UIThreadNative.class);
if (uithreadNative == null) {
Dialog.show("Null implementation", " UIThread is not implemented yet in this platform.", "Ok", null);
throw new RuntimeException("UIThread is not implemented yet in this platform.");
}
}
if (!uithreadNative.isSupported()) {
Dialog.show("Unsupported", " UIThread is not supported in this platform.", "Ok", null);
throw new RuntimeException("UIThread is not supported in this platform.");
}
}
public void runNativeCode() {
uithreadNative.runNativeCode();
}
}
Native implementation for android
package com.uithread.test;
import android.content.Context;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import com.codename1.impl.android.*;
import com.codename1.ui.Dialog;
public class UIThreadNativeImpl {
private static Context context() {
return com.codename1.impl.android.AndroidNativeUtil.getActivity().getApplicationContext();
}
private static Activity activity() {
return com.codename1.impl.android.AndroidNativeUtil.getActivity();
}
public void runNativeCode() {
final Activity convenientActivity = activity();//AndroidNativeUtil.getActivity();
final CodenameOneActivity codenameoneActivity = (CodenameOneActivity) AndroidNativeUtil.getActivity();
final android.app.Activity app = (Activity) AndroidNativeUtil.getActivity();
Dialog.show("Activity", convenientActivity + " convenientActivity", "Ok", null);
Dialog.show("Activity", codenameoneActivity + " codenameoneActivity", "Ok", null);
Dialog.show("Activity", app + " App", "Ok", null);
convenientActivity.runOnUiThread(new Runnable() {
public void run() {
Dialog.show("In run", "Run started", "Ok", null);
}
});
}
public boolean isSupported() {
return true;
}
}
In Statemachine I run this in code on a button click.
#Override
protected void onMain_ButtonAction(Component c, ActionEvent event) {
UIThreadManager uIThreadManager = new UIThreadManager();
uIThreadManager.runNativeCode();
}
As I said earlier. The codes before runOnUiThread work but the codes in runOnUiThread does not work. The dialogs in the runNativeCode in the native implementation were for checking the activity in different flavors which shows correctly that the different flavors are the same.
Thanks.

Answer 1

The native UI thread is totally different from our EDT so showing a Codename One dialog from that thread would be a huge EDT violation that can cause a serious crash!
Since our dialog blocks safely you would be effectively blocking the entire application and crashing it.
We use this line which is pretty much equivalent to what you wrote quite a bit in Codename One and in libraries e.g. here:
AndroidNativeUtil.getActivity().runOnUiThread(new Runnable() { ... });