Android SDK - Using Gesture API, would like gesture to stay on screen after being recognized

Question

I'm using the Gesture API with a Gesture Library that I created, and it is working really well. The problem is that I would like the gesture to be visible on the screen after OnGesturePerformedListener exits, but instead the gesture is erased. I was thinking that perhaps there is an event after OnGesturePerformedListener -- I could save the gesture in OnGesturePerformedListener and then display it again in this later event. Anyone know if there is such an event? Here is the code:

   private OnGesturePerformedListener handleGestureListener = new OnGesturePerformedListener() {
        @Override
        public void onGesturePerformed(GestureOverlayView gestureView,
                                       Gesture gesture) {
            if (gesture.getStrokesCount() != 2){
                setWonderEmoticon();
                return;
            }
            ArrayList<Prediction> predictions = gLib.recognize(gesture);
            // one prediction needed
            if (predictions.size() > 0) {
                Prediction prediction = predictions.get(0);
                // checking prediction
                if (prediction.score > 20.0) {
                    setHappyEmoticon();
                }
                else {
                    setWonderEmoticon();
                }
            }
        }
    };

By the way, the same thing happens when setWonderEmoticon() and setHappyEmoticon() are removed from the code.

Answer 1

Here is an example that works fine with the OnGesturePerformedListener:

MainActivity.java:

// ...

public class MainActivity extends AppCompatActivity implements GestureOverlayView.OnGesturePerformedListener, GestureOverlayView.OnGestureListener {

    GestureOverlayView mGestureView;
    ImageView mImageView;
    TextView mText;
    Paint mPaint;
    Bitmap mBitmap;
    Canvas mCanvas;
    GestureLibrary mGestureLib;

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

        mImageView = (ImageView) findViewById(R.id.image_view);
        mGestureView = (GestureOverlayView) findViewById(R.id.gesture_overlay);
        mGestureView.addOnGesturePerformedListener(this);
        mGestureView.addOnGestureListener(this);

        mGestureView.setGestureColor(Color.BLACK);
        mGestureView.setUncertainGestureColor(Color.BLACK);
        mGestureView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
            @Override
            public void onGlobalLayout() {
                mGestureView.getViewTreeObserver().removeOnGlobalLayoutListener(this);
                mBitmap = Bitmap.createBitmap(mGestureView.getWidth(), mGestureView.getHeight(), Bitmap.Config.ARGB_8888);
                mCanvas = new Canvas(mBitmap);
            }
        });

        mPaint = new Paint();
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setStrokeWidth(12.0f);
        mPaint.setColor(Color.GRAY);

        mText = (TextView) findViewById(R.id.text);

        mGestureLib = GestureLibraries.fromRawResource(getApplicationContext(), R.raw.gesture);
        mGestureLib.load();
    }

    @Override
    public void onGesturePerformed(GestureOverlayView gestureOverlayView, Gesture gesture) {
        if (gesture.getStrokesCount() > 0) {
            ArrayList<Prediction> predictions = mGestureLib.recognize(gesture);
            for (GestureStroke stroke : gesture.getStrokes()) {
                Path path = stroke.getPath();
                mCanvas.drawPath(path, mPaint);
            }
            mImageView.setImageBitmap(mBitmap);
            if (!predictions.isEmpty()) {
                Prediction best = predictions.get(0);
                mText.setText(String.format("Gesture: %s", best.name));
            }
        }
    }

    // ...
}

activity_main.xml (snapshot):

<?xml version="1.0" encoding="utf-8"?>
<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:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="onl.nok.gestures.MainActivity">

    <TextView
        android:id="@+id/text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Waiting ..."
        android:textSize="25sp" />

    <ImageView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/image_view" />

    <android.gesture.GestureOverlayView
        android:id="@+id/gesture_overlay"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gestureStrokeType="single"
        android:fadeEnabled="false" />
</RelativeLayout>

How to apply new gestures?

1. Track gestures with the Android app Gesture Builder
2. Create a resource folder raw in your project: <Project>/app/src/main/res/raw/
3. Copy the generated file gesture.txt from your device: /Android/data/pack.GestureApp/files/gesture.txt
4. And finally paste it to the created folder raw: <Project>/app/src/main/res/raw/gesture.txt

Finally I pushed the source code to GitHub: https://github.com/nok/android-gesture-libraries

---

2nd edit:

You're right. So I use a simple ImageView to draw the performed gestures. Furthermore you can change the style in mPaint of type Paint. You can find all changes in the pushed commit 82eabfb and 5ce427d on GitHub.