在这个例子中自定义了一个View，可以接受touch动作，然后在屏幕上即时的显示出touch的轨迹，类似于线条的屏幕上涂鸦。这个例子主要是演示如何将onTouchEvent与draw配合起来使用。在这个基础上，可以做很多有用的程序。

import android.content.Context; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.Path; import android.graphics.Paint.Style; import android.view.MotionEvent; import android.view.View; /** * Example for hand writing. * * @author * @version 2010/09/07 * */ public class HandwritingView extends View { private Paint paint = null; private Path path = null; public HandwritingView(Context context) { super(context); path = new Path(); paint = new Paint(); paint.setColor(Color.YELLOW); paint.setStyle(Style.STROKE); paint.setAntiAlias(true); this.setBackgroundColor(Color.BLACK); } @Override public boolean onTouchEvent(MotionEvent event) { if (event.getAction() == MotionEvent.ACTION_DOWN) { int x = (int) event.getX(); int y = (int) event.getY(); path.moveTo(x, y); invalidate(); return true; } else if (event.getAction() == MotionEvent.ACTION_MOVE) { int x = (int) event.getX(); int y = (int) event.getY(); path.lineTo(x, y); invalidate(); return true; } return super.onTouchEvent(event); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); if (path != null) { canvas.drawPath(path, paint); } } }