Question

为什么这不起作用？

for (PlayingCard playingCard : Stack0.Cards)
{
    ImageView myImg = new ImageView(this);
    myImg.setImageResource(R.drawable.c2);

    RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(new ViewGroup.LayoutParams(CardWidth, ViewGroup.LayoutParams.WRAP_CONTENT));
    lp.setMargins(0, 0, 0,0);
    //lp.addRule(RelativeLayout.ALIGN_TOP); fails
    //lp.addRule(RelativeLayout.ALIGN_PARENT_TOP); fails
    //lp.addRule(RelativeLayout.ALIGN_START); fails
    lp.addRule(RelativeLayout.ALIGN_PARENT_START);
    myImg.setLayoutParams(lp);
    mat.addView(myImg);
}

xml

<RelativeLayout
    android:id="@+id/PLAY_Mat"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_alignParentStart="true"
    >
</RelativeLayout>

ImageView已成功添加，但它居中垂直。我希望它与顶部对齐。我希望即使没有添加规则也可以这样做，因为“默认情况下，所有子视图都是在布局的左上角绘制的”（RelativeLayout文档）。

Answer 1

试试这段代码：

 RelativeLayout rl = new RelativeLayout(this);

 for (PlayingCard playingCard : Stack0.Cards)
    {
        ImageView myImg = new ImageView(this);
        myImg.setImageResource(R.drawable.c2);

        RelativeLayout.LayoutParams lay = new RelativeLayout.LayoutParams(
                    RelativeLayout.LayoutParams.WRAP_CONTENT, 
                    RelativeLayout.LayoutParams.WRAP_CONTENT);

        lay.setMargins(0, 0, 0,0);
        lay.addRule(RelativeLayout.ALIGN_PARENT_TOP);

        rl.addView(myImg, lay);
        //myImg.setLayoutParams(lp);
        //mat.addView(myImg);
    }

Answer 2

将 MATCH_PARENT 设置为RelativeLayout

RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(new ViewGroup.LayoutParams(CardWidth, ViewGroup.LayoutParams.MATCH_PARENT));

或

您可以使用RelativeLayout

中XML的 getLayoutParams（）

RelativeLayout.LayoutParams lp = parentRelativeImageview.getLayoutParams();

Answer 3

OP解决方案。

此代码有效：

    for (PlayingCard playingCard : Stack0.Cards)
    {
        ImageView myImg = new ImageView(this);
        myImg.setImageResource(R.drawable.a1);

        RelativeLayout.LayoutParams lay = new RelativeLayout.LayoutParams(CardWidth, CardHeight);
        lay.setMargins(playingCard.UI_MarginLeft, playingCard.UI_MarginTop, 0, 0);

        mat.addView(myImg, lay);
    }

这里的关键是CardWidth和CardHeight都已设置，两者都正确。通过正确，我的意思是正确的比率。想要加宽宽度？然后加倍高度等。如果w或h中的一个是像素int，而另一个是WRAP_CONTENT，那么就会出现奇怪现象（图像形式有上边距或左边距）。正确设置w和h后，不需要lp.addRule(RelativeLayout.ALIGN_PARENT_START)。

ALIGN_PARENT_TOP以编程方式不起作用

3 个答案: