这是之前在ListView类中使用divider和dividerHeight参数实现的一个例子:
<ListView
android:id="@+id/activity_home_list_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:divider="@android:color/transparent"
android:dividerHeight="8dp"/>
然而，在RecyclerView类中我没有看到这样的可能性。
<android.support.v7.widget.RecyclerView
android:id="@+id/activity_home_recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scrollbars="vertical"/>
在这种情况下，是否可以定义边距和/或直接添加自定义分隔符视图到列表项的布局中，或者是否有更好的方法来实现我的目标?
为了在RecylerView中实现项目之间的间隔，我们可以使用ItemDecorators:
addItemDecoration(object : RecyclerView.ItemDecoration() {
override fun getItemOffsets(
outRect: Rect,
view: View,
parent: RecyclerView,
state: RecyclerView.State,
) {
super.getItemOffsets(outRect, view, parent, state)
if (parent.getChildAdapterPosition(view) > 0) {
outRect.top = 8.dp // Change this value with anything you want. Remember that you need to convert integers to pixels if you are working with dps :)
}
}
})
对于我粘贴的代码，有几件事需要考虑:
You don't really need to call super.getItemOffsets but I chose to, because I want to extend the behavior defined by the base class. If the library got an update doing more logic behind the scenes, we would miss it.
As an alternative to adding top spacing to the Rect, you could also add bottom spacing, but the logic related to getting the last item of the adapter is more complex, so this might be slightly better.
I used an extension property to convert a simple integer to dps: 8.dp. Something like this might work:
val Int.dp: Int
get() = (this * Resources.getSystem().displayMetrics.density + 0.5f).toInt()
// Extension function works too, but invoking it would become something like 8.dp()
如果有人只想在项目之间添加10dp的间距，你可以通过设置一个drawable到DividerItemDecoration来实现:
DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(
recyclerView.getContext(),
layoutManager.getOrientation()
);
dividerItemDecoration.setDrawable(
ContextCompat.getDrawable(getContext(), R.drawable.divider_10dp)
);
recyclerView.addItemDecoration(dividerItemDecoration);
其中，divider_10dpis一个可绘制资源，包含:
<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle">
<size android:height="10dp"/>
<solid android:color="@android:color/transparent"/>
</shape>
下面是我在Kotlin中如何做的，在项目之间设置一个默认大小为10dp的简单空间:
class SimpleItemDecoration(context: Context, space: Int = 10) : RecyclerView.ItemDecoration() {
private val spaceInDp = ConvertUtil.dpToPx(context, space)
override fun getItemOffsets(outRect: Rect, view: View, parent: RecyclerView, state: RecyclerView.State) {
outRect.left = spaceInDp
outRect.right = spaceInDp
outRect.bottom = spaceInDp
// Add top margin only for the first item to avoid double space between items
if (parent.getChildAdapterPosition(view) == 0) {
outRect.top = spaceInDp
}
}
}
这是dpToPx方法:
fun dpToPx(context: Context, dp: Int): Int {
return (dp * context.resources.displayMetrics.density).toInt()
}
然后像这样将它添加到RecyclerView中:(感谢@MSpeed)
recyclerView.addItemDecoration(SimpleItemDecoration(context))
这很简单，你不需要这么复杂的代码:
DividerItemDecoration divider = new DividerItemDecoration(
mRVMovieReview.getContext(), DividerItemDecoration.VERTICAL
);
divider.setDrawable(
ContextCompat.getDrawable(getBaseContext(), R.drawable.line_divider)
);
mRVMovieReview.addItemDecoration(divider);
将它添加到你的drawable: line_divide .xml中
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<size android:height="1dp" />
<solid android:color="@android:color/black" />
</shape>
