Question

I m trying to refresh the screen on clicking a button so i want to know What should I write in OnClick() method so that the custom view ie TouchEventView will reload or refresh here is my code of
TouchEventView.java

public class TouchEventView extends View {
    private Paint paint = new Paint();
    private Path path = new Path();

    public TouchEventView(Context context, AttributeSet attrs) {
        super(context, attrs);

        paint.setAntiAlias(true);
        paint.setColor(Color.WHITE);
        paint.setStyle(Paint.Style.STROKE);
        paint.setStrokeJoin(Paint.Join.ROUND);
        paint.setStrokeWidth(5f);
    }

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

    @Override
    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;
    }
}
`

here is main.xml file “

    <de.vogella.android.touch.TouchEventView
        android:id="@+id/mydrawview1"
        android:layout_width="wrap_content"
        android:layout_height="328dp"
        android:layout_weight="0.91" />

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal" >

        <Button
            android:id="@+id/reset"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Reset" />
    </LinearLayout>

</LinearLayout>` 

here is activity class`

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    Button res = (Button) findViewById(R.id.reset);
    res.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            TouchEventView touchView = (TouchEventView) findViewById(R.id.mydrawview1);
            touchView.clear();

        }
    });
}

}`

Answer 1

Just add this method to your TouchEventView:

public void clear ()
{
    path = new Path();
    invalidate();
}

And then call it from onClick():

@Override
public void onClick(View v) {
    TouchEventView touchView = (TouchEventView) findViewById(R.id.mydrawview1);
    touchView.clear();
}