button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
startActivity(new Intent(D.this, A.class));
}
});
Declare A in your manifest with the android:launchMode="singleTask"
. This way, when you call startActivity()
from your other activies, and A is already running, it will just bring it to the front. Otherwise it’ll launch a new instance.