1

我有一个封闭的路径，我想用一种颜色（白色）填充它，并在它周围放置另一种颜色（红色）的边缘。我认为自定义视图类可以让我达到这个目的：

public class StrokeFill extends View{
private Path shapePath;
private Paint strokePaint;
private Paint fillPaint;


public StrokeFill(Context context, Path path) {
    super(context);
    shapePath = path;
    fillPaint.setColor(android.graphics.Color.WHITE);
    fillPaint.setStyle(Paint.Style.FILL);
    fillPaint.setStrokeWidth(0);
    strokePaint.setColor(android.graphics.Color.RED);
    strokePaint.setStyle(Paint.Style.STROKE);
    strokePaint.setStrokeWidth(3);
    // TODO Auto-generated constructor stub
}

protected void onDraw(Canvas canvas) {
    // TODO Auto-generated method stub
    //canvas.drawColor(Color.BLACK);
    super.onDraw(canvas);
    canvas.drawPath(shapePath, fillPaint);
    canvas.drawPath(shapePath, strokePaint);
}
}

在我的主要活动中，我只是这样做了（没有 XML 布局文件）：

setContentView(new StrokeFill(this, testpath));

testpath 是我在Activity中定义的路径。这是有效的，因为当我使用它定义 PathShape 时，我能够绘制它。但在这种情况下，Eclipse 给了我错误 java.lang.NullPointerException。我尝试在 XML 布局中定义自定义视图，但这也不起作用。到目前为止，在 android 中使用形状非常令人沮丧，所以如果有人能提供帮助，那就太好了！

4

2 回答 2

1

你的初始化问题看看这个

public class StrokeFill extends View{
    private Path shapePath;
    private Paint strokePaint;
    private Paint fillPaint;

    public StrokeFill(Context context, Path path) {
       super(context);
       shapePath = new Path();        
       shapePath = path;
       fillPaint = new Paint();
       fillPaint.setColor(android.graphics.Color.WHITE);
       fillPaint.setStyle(Paint.Style.FILL);
       fillPaint.setStrokeWidth(0);
       strokePaint = new Paint();
       strokePaint.setColor(android.graphics.Color.RED);
       strokePaint.setStyle(Paint.Style.STROKE);
       strokePaint.setStrokeWidth(3);
       // TODO Auto-generated constructor stub
    }

   protected void onDraw(Canvas canvas) {
      // TODO Auto-generated method stub
      //canvas.drawColor(Color.BLACK);
      super.onDraw(canvas);
      canvas.drawPath(shapePath, fillPaint);
      canvas.drawPath(shapePath, strokePaint);
  }
}
于 2012-07-10T17:03:33.383 回答
0

strokePaint 从未在您的代码中初始化......那是您的 nullPointer 吗？

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于 2012-07-10T16:44:47.773 回答