Android中在屏幕上涂鸦的例子

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这个例子，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 http://blog.csdn.net/arui319  * @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);          }      }  }

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