以编程方式在 RecyclerView 上设置边距

Question

我需要以编程方式在 RecyclerView 上设置上边距，但出现此异常：

java.lang.RuntimeException: Unable to resume activity java.lang.ClassCastException: android.view.ViewGroup$LayoutParams cannot be cast to android.support.v7.widget.RecyclerView$LayoutParams

这是我的代码：

RecyclerView.LayoutParams layoutParams = (RecyclerView.LayoutParams)recyclerView.getLayoutParams();
int marginTopDp = (int)getResources().getDimension(R.dimen.margin);
int marginTopPx = (int) (marginTopDp * getResources().getDisplayMetrics().density + 0.5f);
layoutParams.setMargins(0, marginTopPx, 0, 0);
recyclerView.setLayoutParams(layoutParams);

如果我按照堆栈跟踪建议使用 ViewGroup.LayoutParams layoutParams = recyclerView.getLayoutParams，我将无法再调用 setMargin，因为 ViewGroup.LayoutParams.

不存在该方法

如有任何帮助，我们将不胜感激。

Answer 1

试试这个。您可以参考this了解更多信息。

ViewGroup.MarginLayoutParams marginLayoutParams = new ViewGroup.MarginLayoutParams(mRecyclerView.getLayoutParams());
marginLayoutParams.setMargins(0, 10, 0, 10);
mRecyclerView.setLayoutParams(marginLayoutParams);

Answer 2

您需要使用 MarginLayoutParams 的新对象

    final FrameLayout.MarginLayoutParams marginLayoutParams = new      
                      FrameLayout.MarginLayoutParams(rvContacts.getLayoutParams());
    marginLayoutParams.leftMargin = left;
    marginLayoutParams.topMargin = top;
    marginLayoutParams.rightMargin = right;
    marginLayoutParams.bottomMargin = bottom;

    recyclerView.setLayoutParams(marginLayoutParams);
    recyclerView.requestLayout();

Answer 3

对我来说，recyclerview 的父级是 constraintLayout、

        val margins = (rv.layoutParams as ConstraintLayout.LayoutParams).apply {
        leftMargin = 0
        rightMargin = 0
    }
    rv.layoutParams = margins

否则会出现转换错误，viewGroup.LayoutParams不能转换为COnstarintLayout.LayoutParams

Answer 4

我也面临这种问题，使用下面的代码来处理recyclerview的保证金问题。

    ViewGroup.MarginLayoutParams marginLayoutParams=
    (ViewGroup.MarginLayoutParams) recyclerView.getLayoutParams();

    // here i try to set only top margin, Get dimension from dimension file.
    int topMargin =  getResources()
    .getDimensionPixelSize(R.dimen.top_margin);

    marginLayoutParams.setMargins(marginLayoutParams.getMarginStart(),
    topMargin, marginLayoutParams.getMarginEnd(), marginLayoutParams.bottomMargin);

    recyclerView.setLayoutParams(marginLayoutParams);

Answer 5

在我的案例中，使用 clipToPadding="false" 填充就可以了。 [科特林]

所以我在 xml 中将 android:clipToPadding="false" 添加到我的 RecyclerView。也可以通过编程方式完成。

然后刚刚使用：

recyclerView.setPadding(10, 0, 0, someSpace)

someSpace 是 dp 变量，以备不时之需。

resources.getDimension(R.dimen.some_space).toInt() P.S 不要忘记在维度文件中创建 some_space :)

以编程方式在 RecyclerView 上设置边距

Set Margin on RecyclerView programmatically

android

layoutparams

android-recyclerview