// java.lang.NullPointerException: Attempt to read from field 'android.graphics.Bitmap pt.isec.tp.am.Background.bitmap' on a null object reference
// at pt.isec.tp.am.Surface.onDraw(Surface.java:123)
// at android.view.View.draw(View.java:16184)
// at android.view.SurfaceView.draw(SurfaceView.java:341)
// at android.view.View.draw(View.java:16096)
// at android.view.ViewGroup.drawChild(ViewGroup.java:3609)
// at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3399)
// at android.view.View.draw(View.java:16094)
// at android.view.ViewGroup.drawChild(ViewGroup.java:3609)
// at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3399)
// at android.view.View.draw(View.java:16094)
// at android.view.ViewGroup.drawChild(ViewGroup.java:3609)
// at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3399)
// at android.view.View.draw(View.java:16187)
// at com.android.internal.policy.PhoneWindow$DecorView.draw(PhoneWindow.java:2690)
// at android.view.ViewRootImpl.drawSoftware(ViewRootImpl.java:2728)
// at android.view.ViewRootImpl.draw(ViewRootImpl.java:2642)
// at android.view.ViewRootImpl.performDraw(ViewRootImpl.java:2434)
// at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2067)
// at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1107)
// at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6013)
// at android.view.Choreographer$CallbackRecord.run(Choreographer.java:858)
// at android.view.Choreographer.doCallbacks(Choreographer.java:670)
// at android.view.Choreographer.doFrame(Choreographer.java:606)
// at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:844)
// at android.os.Handler.handleCallback(Handler.java:739)
// at android.os.Handler.dispatchMessage(Handler.java:95)
// at android.os.Looper.loop(Looper.java:148)
// at android.app.ActivityThread.main(ActivityThread.java:5417)
// at java.lang.reflect.Method.invoke(Native Method)
// at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
// at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)