TouchDraw.java

package test;

import android.app.Activity;
import com.example.canv.R;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Point;
import android.os.Bundle;
import android.util.Log;
import android.view.Display;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.ImageView;

public class TouchDraw extends Activity implements OnTouchListener {
  ImageView imageView;
  Bitmap bitmap;
  Canvas canvas;
  Paint paint;
  float downx = 0, downy = 0, upx = 0, upy = 0;
  float lastX = 0, lastY = 0;

    boolean isNew = true;
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_touch_draw);

    imageView = (ImageView) this.findViewById(R.id.imageView1);

    Display currentDisplay = getWindowManager().getDefaultDisplay();
    Point size = new Point();
    currentDisplay.getSize(size);

    bitmap = Bitmap.createBitmap((int) size.x, (int) size.y,
        Bitmap.Config.ARGB_8888);
    canvas = new Canvas(bitmap);
    paint = new Paint();
    paint.setStrokeWidth(5);
    paint.setColor(Color.GREEN);
    imageView.setImageBitmap(bitmap);

    imageView.setOnTouchListener(this);
  }

  public boolean onTouch(View v, MotionEvent event) {
    int action = event.getAction();


    switch (action) {
    case MotionEvent.ACTION_DOWN:
      isNew = true;
      Log.w("onTouch", ("X: " + event.getX() + ", Y: " + event.getY()));
      canvas.drawCircle(event.getX(), event.getY(), paint.getStrokeWidth()/2, paint);
      imageView.invalidate();
      /*
      downx = event.getX();
      downy = event.getY();
      break;*/
    case MotionEvent.ACTION_MOVE:
        //canvas.drawCircle(event.getX(), event.getY(), 1, paint);
        float x, y;
        x = event.getX();
        y = event.getY();

        if(!isNew)
        {
            canvas.drawLine(lastX, lastY, x, y, paint);
            canvas.drawCircle(x, y, paint.getStrokeWidth()/2, paint);
            imageView.invalidate();
        }
        else
        {
            isNew = false;
        }

        lastX = x;
        lastY = y;

      break;
    /*case MotionEvent.ACTION_UP:
      upx = event.getX();
      upy = event.getY();
      canvas.drawLine(downx, downy, upx, upy, paint);
      imageView.invalidate();
      break;
    case MotionEvent.ACTION_CANCEL:
      break;
    default:
      break;*/
    }
    return true;
  }
}