SurfaceView and ANativeWindow

Question

I have a question regarding creation of a SurfaceView and subsequently getting a ANativeWindow from it.

1. Is it proper to do
   
   mSurfaceView = new SurfaceView(this); in:
   
   
   • onCreate()
   • onStart()

Reason for asking: as I understand it the SurfaceView will get destroyed when we lose focus (something else covers up the entire screen) so we will need to re-create it every time we gain focus (onStart() is executed). Or does the SurfaceView remain dormant and reusable?

1. Moving on, now I would like to create a native window from the above-mentioned surface (in native code). Is it proper to do
   
   ANativeWindow* newwindow = ANativeWindow_fromSurface(jniEnv, joSurface) in:
   

   • onSurfaceCreated_native(..., jobject surface)
   • onSurfaceChanged_native(..., jobject surface)

Reason for asking: onSurfaceChanged seems to be always called after onSurfaceCreated so we have a choice as to when to create the native window. On one hand, it appears logical to do this in onSurfaceCreated, but the two jobject surface appear to be referencing different objects! (As checked by creating a weak global ref to surface in onSurfaceCreated and checking it against both NULL and surface in onSurfaceChanged, see code below)

onSurfaceCreated_native(JNIEnv env, ... ,jobject surface) {
myWeakObjectGlobal = env->NewWeakGlobalRef(surface);
}

onSurfaceChanged_native(JNIEnv env, ... ,jobject surface) {

if (env->IsSameObject(surface, myWeakObjectGlobal)) {
    LOGW("onSurfaceChanged_native: new surface is SAME as old surface");
} else {
    LOGW("onSurfaceChanged_native: new surface is DIFFERENT as old surface");
}

if (env->IsSameObject(NULL, myWeakObjectGlobal)) {
    LOGW("    furthermore, old surface is NULL");
} else {
    LOGW("    furthermore, old surface is NOT null");
}

}

Therefore, if there are indeed two distinct surface objects being sent into onSurfaceCreated and onSurfaceChanged, then we want to use the freshest one and not hang on to a stale surface reference, and consequently do ANativeWindow_from_Surface in onSurfaceChanged.

I would really appreciate it if someone could shine some light on this issue for me.

Answer 1

Have you tried using android.view.Surface instead of android.view.SurfaceView?