Hexagon button with hexagon touch area

Question

I need to create the same buttons like in the picture below. Button's must be with the text inside.

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When I was making XML layout I encountered with a problem of Button's touch area. Each next button is cover previous button with a rectangular Button's area.

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Is it right to place hexagons in the XML markup like I done, to implement hexagons like in picture? Please, help me to solve problem with touch area and if possible tell me how to create a layout right, because I'm not sure that since I'm doing is correctly.

Here is part of my test layout:

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical"
            android:layout_marginTop="?attr/actionBarSize">


            <Button
                android:id="@+id/button1"
                android:layout_width="130dp"
                android:layout_height="134dp"
                android:background="@drawable/hexagon_shape_img"
                android:text="Home page"
                android:textSize="@dimen/small_text" />

            <Button
                android:id="@+id/button2"
                android:layout_width="130dp"
                android:layout_height="134dp"
                android:layout_marginLeft="65dp"
                android:layout_marginTop="-20dp"
                android:background="@drawable/hexagon_shape_img"
                android:text="Tavern"
                android:textSize="@dimen/small_text" />

        </LinearLayout>

Answer 1

Ok, this turned out to be more complicated than I thought. The basic problem is that the highest Z-ordered button always gets the touch event, but doesn't pass it on the the lower Z-orders even if it doesn't dispose of the event. To get both buttons to see the event, a work-around is needed. Here's the basic approach:

1: Create a container in the Fragment/Activity that currently holds your hex buttons

2: Create a Fragment that contains the buttons and another button on top of all of them with alpha=0

3: Add a getOverlay():View method that returns that alpha=0 button

4: implement a hitTest():Button method in the fragment

5: In the main Activity/Fragment, set up listeners to handle the touch events of the overlay button

I made (and tested) an Application to demonstrate the concept. I'm going to leave the hitTest to you as it's rather tedious

activity_main.xml:

<RelativeLayout 
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" 
android:layout_width="match_parent"
android:layout_height="match_parent" 
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin" 
tools:context=".MainActivity">

    <FrameLayout android:id="@+id/main_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

</RelativeLayout>

fragment_buttons.xml:

<FrameLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.me.testapplication.Buttons">

    <Button android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/lorem"/>
    <Button android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/lorem_ipsum"
        android:alpha="0.4"/>
    <Button android:id="@+id/overlay"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:alpha="0"/>

</FrameLayout>

MainActivity.java:

public class MainActivity extends ActionBarActivity {
    public static final String DEBUG_TAG = "TEST";

    private Buttons mButtons;
    private GestureDetector mGestureDetector;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mButtons = Buttons.newInstance();
        getFragmentManager().beginTransaction()
                .replace(R.id.main_container, mButtons)
                .commit();

        mGestureDetector = new GestureDetector(this, mGestureListener);
    }

    @Override
    protected void onStart() {
        super.onStart();

        View overlay = mButtons.getOverlay();
        if (overlay != null) {
            overlay.setOnTouchListener(mTouchListener);
        }
    }
    ...
    private View.OnTouchListener mTouchListener = new View.OnTouchListener() {
        @Override
        public boolean onTouch(View v, MotionEvent event) {
             return mGestureDetector.onTouchEvent(event);
        }
    };

    private GestureDetector.OnGestureListener mGestureListener
            =new GestureDetector.OnGestureListener()
    {
            @Override
            public boolean onDown(MotionEvent e) {
            String buttonHit = mButtons.hitTest(e);
            Log.i(DEBUG_TAG, buttonHit);
            return true;
        }
        ...
    };
}

Buttons.java:

public class Buttons extends Fragment {

    Button mButton1, mButton2;
    View mOverlay;

    public static Buttons newInstance() {
        return new Buttons();
    }

    public Buttons() {}

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View root = inflater.inflate(R.layout.fragment_buttons, container, false);
        mButton1 = (Button) root.findViewById(R.id.button1);
        mButton2 = (Button) root.findViewById(R.id.button2);
        mOverlay = root.findViewById(R.id.overlay);
        return root;
    }

    @Nullable
    public View getOverlay() {
        return mOverlay;
    }

    public String hitTest(MotionEvent event) {
        float x = event.getX();
        float y = event.getY();

        if (x > mButton1.getLeft() && mButton1.getRight() > x &&
                y > mButton1.getTop() && mButton1.getBottom() > y)
        {
            return "Button 1";
        } else if (x > mButton2.getLeft() && mButton2.getRight() > x &&
                y > mButton2.getTop() && mButton2.getBottom() > y)
        {
            return "Button 2";
        } else {
            return "None";
        }
    }
}

Good luck.

ETA: Sample hitTest

/**
 * UNTESTED
 * I'm going to assume square buttons (equilateral hexagons)
 * this just calculates if the distance from the center of the button is less than its width. It may be good enough for government work.
 */
public View hitTest(MotionEvent e) {
    for (Button hex : SomeIterableThingHoldingYourButtons) { //ArrayList<Button> maybe
        float x = e.getX();
        float y = e.getY();

        if (isInHex(hex, x, y)) return hex;
     }
     return null;
}

private boolean isInHex(Button hex, float x, float y) {
    float radius = hex.getRight() - hex.getLeft() / 2;
    float centerX = hex.getLeft() + radius;
    float centerY = hex.getTop() + radius;

    float dist = FloatMath.sqrt(...) //euclidean distance

    return dist < radius;
}