Andengine swipe navigation

Question

I am new to andengine and want to know that how I can switch between two BaseGameActivities. And also when switching from first activity to second, there is no black screen transition in between switching. Is there any possible way to do it. Please help me out.

Answer 1

A BaseGameActivity can be used as any other Android Activity, too:

Intent intent = new Intent(this, MyOtherBaseGameActivity.class);
startActivity(intent);

So if you want to change from your program to another app (maybe by opening the browser…) you can do that as with any other Android App, too. However if both Activities are part of your own App, there is rarely a case where this is recommendable (It is like starting a second program). Although it is possible to exchange data between the activities as described in this post.

But maybe you are only looking for a way to switch between Views in AndEngine. If that's the case you can switch between Scenes without any transition necessary.

MyOtherScene secondScene = new MyOtherScene();
mEngine.setScene(secondScene);

That way you can switch between what is being displayed, without needing to load every image again.

EDIT:

Since you can't use AndEngine to switch between Activities, nor is a smooth switching between scenes possible. Here a quick example on how to switch between two screens (e.g. menus). In this example the screens are actually 2 different images (as big as the display … maybe some background images). Note: there is no such thing as 'screens' in AndEngine, it is simply a self made class that extends Entity.

Your Screen

public MyScreen extends Entity{

    private float firstX;
    public MyScreen(Sprite niceBackgroundImage1, Sprite niceBackgroundImage2){
        this.attachChild(niceBackgroundImage1);    // attach something to the screen, so you can see it (preferably an image that is as big as your camera)
        this.attachChild(niceBackgroundImage2); 
        this.firstY=-1;   // this is a variable to remember the first x coordinate touched
    }

    @Override
    public boolean onAreaTouched(TouchEvent sceneTouchEvent, float touchAreaLocalX, float touchAreaLocalY) {
        if(sceneTouchEvent.getAction()==TouchEvent.ACTION_DOWN){
            this.firstY=touchAreaLocalX;  // remember the x, on the first touch
        } 
        if(sceneTouchEvent.getAction()==TouchEvent.ACTION_MOVE){
            if(touchAreaLocalX>firstY+20){
                 // user swiped from left to right (at least 20 pixels)
                 niceBackgroundImage1.registerEntityModifier(new MoveModifier(3f, 0, niceBackgroundImage1.getWidth(), 0, 0, EaseBounceOut.getInstance()));
                 // the last line actualy moves the nice..image1 from left to right (in 3 seconds) and lets it bounce a little bit before it is completely out of the screen
                 return true;
            }
        }
        return false;
    }
    ...
}

Your Activity

private HUD hud;          // create a  HUD

...
@Override
protected void onCreateResources() {         
   this.hud = new HUD();                // init the HUD
   this.myScreen = new MyScreen(image1, image2)  // init the screen
   this.hud.attachChild(myScreen);     // attach the screen to the hud
   mEngine.getCamera().setHud(hud);  // attach your HUD to the camera
}

@Override
protected Scene onCreateScene() {
   Scene myScene = new Scene();
   myScene.registerTouchArea(myScreen);   // you have to register the touch area of your Screen Class to the scene.
   mEngine.setScene(myScene);
}

And this is how it works:

you create yourself a own screen class that extends Entity. An Entity can be everything visible in AndEngine (like a Sprite, Rectangle or even a whole scene). Put something in your screen class to make it look nice, preferably a big image that fills the whole display. That image will be responsible to register the touch afterwards. If the image is too small and the user misses the image, then no touch will be registered.

In this case I attach the instance of MyScreen to the cameras HUD. That way it will be at a fixed position on the display and it will have a fixed size (just in case you want to make the scene scrollable or zoomable).

Now when the app starts the HUD will be created and attached to the camera and with it your MyScreen class. Then the scene will be created and the screen's area will be registered as touch area to the scene. When a swipe movement on a horizontal axis gets noticed by the screen class, the first image will move outside the screen (in the same direction as the swipe).

But be careful, this is just an example. There is nothing defined on how the touch has to act when the first image was moved outside the screen or how big the screen actually is etc...

I know this is quite a long example, maybe it won't even work the first time and it is definitely not the only way on how switching between different screens can be done. But it shows you how to override the onAreaTouched() method and register the entity modifier to make the image move. Hopefully it will lead you in the right direction, to accomplish what you want to do.