Android Canvas Draw by finger

Question

On a project I’m working on at my current job, I’ve come across some really pernicious problems where there is either

no good information available or
the go         


        

Answer 1

1. Create a class that extends View and paste below code.

public class CustomClass extends View {

  private Paint paint = new Paint();
  private Path path = new Path();

  public CustomClass(Context context, @Nullable AttributeSet attrs) {
    super(context, attrs);
    paint.setAntiAlias(true);
    paint.setStrokeWidth(5 f);
    paint.setColor(Color.BLACK);
    paint.setStyle(Paint.Style.STROKE);
    paint.setStrokeJoin(Paint.Join.ROUND);
  }

  @Override protected void onDraw(Canvas canvas) {
    canvas.drawPath(path, paint);
  }

  @Override public boolean onTouchEvent(MotionEvent event) {
    // Get the coordinates of the touch event.
    float eventX = event.getX();
    float eventY = event.getY();

    switch (event.getAction()) {
      case MotionEvent.ACTION_DOWN:
        // Set a new starting point
        path.moveTo(eventX, eventY);
        return true;
      case MotionEvent.ACTION_MOVE:
        // Connect the points
        path.lineTo(eventX, eventY);
        break;
      default:
        return false;
    }

    // Makes our view repaint and call onDraw
    invalidate();
    return true;
  }

}

2 In XML, paste below code

3 Your MainActivity

public class MainActivity extends AppCompatActivity {

  ImageView imageView;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    imageView = findViewById(R.id.image);
  }

  public void saveImage(View view) {
    View v = findViewById(R.id.custom_view);
    int canvasWidth = v.getWidth();
    int canvasHeight = v.getHeight();
    Bitmap bitmap = Bitmap.createBitmap(canvasWidth, canvasHeight, Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(bitmap);
    v.draw(canvas);
    imageView.setImageBitmap(bitmap);

  }

}

That's it.