improve control, dead zone

src/se/forskningsavd/NavigationView.java

@@ -9,8 +9,17 @@
 import static android.view.MotionEvent.*;
 
 class NavigationView extends View {
+    private static final float DEADZONE = 0.1f; // 0..1
     private final Paint mPaint = new Paint();
     private final Navigator mNavigator;
+    private int mMoveCenterX;
+    private int mMoveCenterY;
+    private int mMoveDistanceX;
+    private int mMoveDistanceY;
+    private int mLookCenterX;
+    private int mLookCenterY;
+    private int mLookDistanceX;
+    private int mLookDistanceY;
 
     public NavigationView(Context context, Navigator navigator) {
         super(context);
@@ -19,14 +28,31 @@ public NavigationView(Context context, Navigator navigator) {
         mPaint.setStyle(Paint.Style.STROKE);
     }
 
+    @Override
+    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
+        super.onSizeChanged(w, h, oldw, oldh);
+
+        mMoveCenterX = w / 4;
+        mLookCenterX = w * 3 / 4;
+        mMoveCenterY = mLookCenterY = h / 2;
+
+        mMoveDistanceX = mLookDistanceX = w / 4;
+        mMoveDistanceY = mLookDistanceY = h / 2;
+    }
+
     @Override
     protected void onDraw(Canvas canvas) {
-        final int width = getWidth();
-        final int height = getHeight();
-        canvas.drawLine(0, height / 3, width, height / 3, mPaint);
-        canvas.drawLine(0, height * 2 / 3, width, height * 2 / 3, mPaint);
-        canvas.drawLine(width / 3, 0, width / 3, height, mPaint);
-        canvas.drawLine(width * 2 / 3, 0, width * 2 / 3, height, mPaint);
+        drawRings(canvas, mMoveCenterX, mMoveCenterY, mMoveDistanceX, mMoveDistanceY, mPaint);
+        drawRings(canvas, mLookCenterX, mLookCenterY, mLookDistanceX, mLookDistanceY, mPaint);
+    }
+
+    private void drawRings(Canvas canvas, int centerX, int centerY, int radiusX, int radiusY, Paint paint) {
+        final int minRadius = Math.min(radiusX, radiusY);
+        final int rings = minRadius / 30;
+        final float ringDistance = (float) minRadius / rings;
+        for (int i = 0; i < rings; i++) {
+            canvas.drawCircle(centerX, centerY, (i + 1) * ringDistance, paint);
+        }
     }
 
     @Override
@@ -36,18 +62,20 @@ public boolean onTouchEvent(MotionEvent event) {
             return true;
         case ACTION_MOVE:
         case ACTION_DOWN:
-            final int width = getWidth();
-            final int height = getHeight();
-
             for (int i = 0; i < event.getPointerCount(); i++) {
                 final float x = event.getX(i);
                 final float y = event.getY(i);
-                if (x < width / 2) {
-                    mNavigator.moveX = (x - width / 4) / (width / 4);
-                    mNavigator.moveY = (y - height / 2) / (height / 2);
-                } else {
-                    mNavigator.rotation = (x - width / 2 - width / 4) / (width / 4);
-                    mNavigator.cameraAngle = (y - height / 2) / (height / 2);
+                final float moveX = normalizeAxis(x, mMoveCenterX, mMoveDistanceX);
+                final float moveY = normalizeAxis(y, mMoveCenterY, mMoveDistanceY);
+                final float lookX = normalizeAxis(x, mLookCenterX, mLookDistanceX);
+                final float lookY = normalizeAxis(y, mLookCenterY, mLookDistanceY);
+
+                if (Math.abs(moveX) <= 1.f && Math.abs(moveY) <= 1.f) {
+                    mNavigator.moveX = moveX;
+                    mNavigator.moveY = moveY;
+                } else if (Math.abs(lookX) <= 1.f && Math.abs(lookY) <= 1.f) {
+                    mNavigator.rotation = lookX;
+                    mNavigator.cameraAngle = lookY;
                 }
             }
             /*
@@ -66,4 +94,14 @@ public boolean onTouchEvent(MotionEvent event) {
             return false;
         }
     }
+
+    private float normalizeAxis(float actual, int reference, int maxDistance) {
+        float d = actual - reference;
+        final float dead = DEADZONE * maxDistance;
+        if (Math.abs(d) < dead) {
+            return 0;
+        }
+        d += (d > 0 ? dead : -dead);
+        return (d / maxDistance);
+    }
 }