Question

I have a class which is under a test with Robotium, in it’s onPause() method I just clear the EditText (I don’t need the data to be preserved after onPause()).

So I have in a class which is under a test:

@Override
protected void onPause() {
    super.onPause();
    mEdtPassword.setText("");
}

and testing method:

public void testOnPauseOnStart() {
        Activity mActivity = getActivity();
        solo.typeText(0, CORRECT_PASSWORD);

        getInstrumentation().callActivityOnPause(mActivity);
    }

But then I got an error:

android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
at android.view.ViewRootImpl.checkThread(ViewRootImpl.java:4746)
at android.view.ViewRootImpl.invalidateChildInParent(ViewRootImpl.java:854)
at android.view.ViewGroup.invalidateChild(ViewGroup.java:4077)
at android.view.View.invalidate(View.java:10322)
at android.widget.TextView.invalidateRegion(TextView.java:4395)
at android.widget.TextView.invalidateCursor(TextView.java:4338)
at android.widget.TextView.spanChange(TextView.java:7186)
at android.widget.TextView$ChangeWatcher.onSpanAdded(TextView.java:8821)
at android.text.SpannableStringBuilder.sendSpanAdded(SpannableStringBuilder.java:979)
at android.text.SpannableStringBuilder.setSpan(SpannableStringBuilder.java:688)
at android.text.SpannableStringBuilder.setSpan(SpannableStringBuilder.java:588)
at android.text.Selection.setSelection(Selection.java:76)
at android.text.Selection.setSelection(Selection.java:87)
at android.text.method.ArrowKeyMovementMethod.initialize(ArrowKeyMovementMethod.java:302)
at android.widget.TextView.setText(TextView.java:3555)
at android.widget.TextView.setText(TextView.java:3425)
at android.widget.EditText.setText(EditText.java:80)
at android.widget.TextView.setText(TextView.java:3400)
at <package>.ui.CheckPasswordActivity.onPause(CheckPasswordActivity.java:182)

If I use solo.setActivityOrientation(Solo.LANDSCAPE) I don’t get this error.

Then if I wrap the mEdtPassword.setText("") with runOnUiThread() everything is fine.

So the questions are:

1. Why I don’t have this exception when I use solo.setActivityOrientation() but I do when I use getInstrumentation().callActivityOnPause(mActivity), I presume both are doing the same thing.

2. Shall I wrap things like mEdtPassword.setText("") in onPause() with runOnUiThread somewhere else for some other reasons or I just need it for testing purposes?

3. Does it mean if I want to have tests of my UI I need to write more code (like running ordinar operations on UI thread) to make it possible to run them?

Thank you very much for clarification.

Answer 1

Praful is mostly correct although I believe you are unable to use instrumentations methods within a test annotated with @UiThreadTest. This means your best option is in fact to wrap instrumentations method in a runnable that you can post to the main thread. for instance:

public void callActivityOnPause(final Activity activity){
    getInstrumentation().runOnMainSync(new Runnable() {
            public void run() {
                activity.onpause();
            }
        });
}

I havent tried this code, so its probably wrong, just killing time on the train!