android - 在Android中的特定区域上绘画

Question

我想画出具体的Line，Rectangle或者Bitmap使用Canvas. 如果我在位图上绘制，它也会采用方形空背景。

所以我只想画出那个特定的Bitmap区域。

Answer 1

从您想要的图像中创建一个名称为“bmp1”的位图
创建一个自定义视图
创建一个类并像这样扩展视图

class MyCustomView extends View{

private Rect m_ImageRect;
private Rect m_TextRect ;

//you need these constructor
//you can init paint object or anything on them
public MyCustomView (Context context, AttributeSet attrs, int defStyle)
{
    super(context, attrs, defStyle);
    m_Context = context;

}

public MyCustomView (Context context, AttributeSet attrs)
{
    super(context, attrs);
    m_Context = context;

}

public MyCustomView (Context context)
{
    super(context);
    m_Context = context;

}

//then override on draw method
@Override
protected void onDraw(Canvas canvas)
{
    super.onDraw(canvas);
            //here frist create two rectangle
            //one for your image and two for text you want draw on it
    m_ImageRect = canvas.getClipBounds();
        m_TextRect = canvas.getClipBounds();
            //it gives you an area that can draw on it,
            //the width and height of your rect depend on your screen size device
            canvas.drawBitmap(your bitmap(bmp1), null, m_ImageRect , paint);
            canvas.save();
    canvas.clipRect(m_TextRect);

            canvas.drawText("your text", the x position you want to start draw,
            the y position you want to start draw, m_paintText);

            canvas.restore();
}
}

最后将自定义视图放在您的布局上，并在其上设置字段以将值发送到视图以绘制您想要的所有内容

我希望它对你有所帮助，如果这不是你想要的！
发布您的代码，也许我可以为您提供更多帮助

Answer 2

好像你需要剪辑。参见示例：http ://www.example8.com/category/view/id/15543 ，了解 Android 画布裁剪， http: //jtomlinson.blogspot.com/2008/10/clipping.html

通过剪辑，您可以指定哪些区域应该是“可编辑的”。