Exercise : 20

Create an application to draw line on the screen as user drag his finger.

Screen Shot:

XML :
main.xml :

JAVA :

TwentyActivity.java :

package kmn.Twenty;
import android.app.Activity;
import android.os.Bundle;
public class TwentyActivity extends Activity 
{
 /**  @author Y@@D  */
    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
  super.onCreate(savedInstanceState);
  setContentView(new ExploreTouchEvent(this, null));
 }
}

ExploreTouchEvent.java :

package kmn.Twenty;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
/**  @author Y@@D  */
public class ExploreTouchEvent extends View 
{
 private Paint paint = new Paint();
 private Path path = new Path();
 public ExploreTouchEvent(Context context, AttributeSet attrs) 
 {
  super(context, attrs);
  paint.setAntiAlias(true);
  paint.setStrokeWidth(6f);
  paint.setColor(Color.WHITE);
  paint.setStyle(Paint.Style.STROKE);
  paint.setStrokeJoin(Paint.Join.ROUND);
 }
 protected void onDraw(Canvas canvas) 
 {
  canvas.drawColor(Color.BLUE);
  canvas.drawPath(path, paint);
  
 }
 public boolean onTouchEvent(MotionEvent event) 
 {
  float eventX = event.getX();
  float eventY = event.getY();
  switch (event.getAction()) 
  {
   case MotionEvent.ACTION_DOWN:
    path.moveTo(eventX, eventY);
    return true;
   case MotionEvent.ACTION_MOVE:
    path.lineTo(eventX, eventY);
    break;
   case MotionEvent.ACTION_UP:
    // nothing to do
    break;
   default:
    return false;
  }
  // Schedules a repaint.
  invalidate();
  return true;
 }
}