RecyclerView in SwipeRefreshLayout not “wrap_content”

问题

I have a RecyclerView as the only child of SwipeRefreshLayout, I want the RecyclerView wrap_content. When I set both of them "wrap_content", it doesn't work. The RecyclerView with fewer items also match_parent. When i delete SwipeRefreshLayout, the RecyclerView will wrap_content. Can anyone help me? My English is poor, Maybe you cann't understand. Anyone can help me? Thank you very much.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/container_v"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.v4.widget.SwipeRefreshLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#00ffff">

        <android.support.v7.widget.RecyclerView
            android:id="@+id/recycler_view"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="#ff00ff">

    </android.support.v7.widget.RecyclerView>

</android.support.v4.widget.SwipeRefreshLayout>

回答1:

Finally, I work out it. From this Answer

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/container_v"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.v4.widget.SwipeRefreshLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#00ffff">

        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="vertical">

            <android.support.v7.widget.RecyclerView
                android:id="@+id/recycler_view"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:background="#ff00ff"/>

        </LinearLayout>
    </android.support.v4.widget.SwipeRefreshLayout>
</LinearLayout>

回答2:

The key is to use Layout wrap RecyclerView. Beacause of SwipeRefreshLayout use MeasureSpec.EXACTLY mode measure mTarget size when onMeasure()：

    public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        if (mTarget == null) {
            ensureTarget();
        }
        if (mTarget == null) {
            return;
        }
        mTarget.measure(MeasureSpec.makeMeasureSpec(
                getMeasuredWidth() - getPaddingLeft() - getPaddingRight(),
                MeasureSpec.EXACTLY), MeasureSpec.makeMeasureSpec(
                getMeasuredHeight() - getPaddingTop() - getPaddingBottom(), MeasureSpec.EXACTLY));
        ......
    }

And mTarget is the first child view of SwipeRefreshLayout. So this will cause the mTarget always match parent.

    private void ensureTarget() {
        // Don't bother getting the parent height if the parent hasn't been laid
        // out yet.
        if (mTarget == null) {
            for (int i = 0; i < getChildCount(); i++) {
                View child = getChildAt(i);
                if (!child.equals(mCircleView)) {
                    mTarget = child;
                    break;
                }
            }
        }
    }

FrameLayout is used because it is more lightweight.

    <androidx.swiperefreshlayout.widget.SwipeRefreshLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <FrameLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <androidx.recyclerview.widget.RecyclerView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:paddingTop="10dp"
                android:paddingBottom="10dp"
                tools:itemCount="2"
                tools:listitem="@layout/item_msg_detail_text_style" />

        </FrameLayout>

    </androidx.swiperefreshlayout.widget.SwipeRefreshLayout>

来源：https://stackoverflow.com/questions/40945022/recyclerview-in-swiperefreshlayout-not-wrap-content