RecyclerView#onMeasure()方法没有通过调用setMeasuredDimension()来设置测量尺寸。

Question

我有一个带有 RecyclerView 的片段，其中使用了 LinearSnapHelper 来将视图放在中心，并通过缩放其大小来突出显示它。

它一直很好地运作着，但当按下返回键从后退栈中弹出该片段时，会抛出以下异常。

E/UncaughtException: java.lang.IllegalStateException: View with id 2131689939: android.support.v7.widget.RecyclerView#onMeasure() did not set the measured dimension by calling setMeasuredDimension()
at android.view.View.measure(View.java:19746)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6120)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1464)
at android.widget.LinearLayout.measureHorizontal(LinearLayout.java:1117)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:642)
at android.view.View.measure(View.java:19734)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6120)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1464)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:758)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:640)
at android.view.View.measure(View.java:19734)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6120)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1464)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:758)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:640)
at android.view.View.measure(View.java:19734)
at android.support.v4.widget.NestedScrollView.measureChildWithMargins(NestedScrollView.java:1420)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
at android.support.v4.widget.NestedScrollView.onMeasure(NestedScrollView.java:482)
at android.view.View.measure(View.java:19734)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6120)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
at android.view.View.measure(View.java:19734)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6120)
at android.support.design.widget.CoordinatorLayout.onMeasureChild(CoordinatorLayout.java:714)
at android.support.design.widget.HeaderScrollingViewBehavior.onMeasureChild(HeaderScrollingViewBehavior.java:90)
at android.support.design.widget.AppBarLayout$ScrollingViewBehavior.onMeasureChild(AppBarLayout.java:1391)
at android.support.design.widget.CoordinatorLayout.onMeasure(CoordinatorLayout.java:784)
at android.view.View.measure(View.java:19734)
at android.support.v4.widget.DrawerLayout.onMeasure(DrawerLayout.java:1081)
at android.view.View.measure(View.java:19734)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6120)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:139)
at android.view.View.measure(View.java:19734)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6120)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1464)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:758)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:640)
at android.view.View.measure(View.java:19734)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6120)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
at android.view.View.measure(View.java:19734)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6120)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1464)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:758)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:640)
at android.view.View.measure(View.java:19734)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6120)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
at com.android.internal.policy.DecorView.onMeasure(DecorView.java:687)
at android.view.View.measure(View.java:19734)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2271)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1358)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1607)

RecyclerView的相关代码如下：

https://gist.githubusercontent.com/anonymous/81a2ae091ded158839b6353ddb03163f/raw/1aff18064d4de4e42b79aa50ff8d44bd6df365a9/Main.java

- Gurpreet Kaur

---

你找到了什么吗？ - Kevin Robatel

Answer 1

我认为这是因为我们正在使用一个已经与 RecyclerView 相关联的 LayoutManager 调用 RecyclerView.setLayoutManager()。

public void setLayoutManager(LayoutManager layout) {
    ...
    if (layout != null) {
        if (layout.mRecyclerView != null) {
            throw new IllegalArgumentException("LayoutManager " + layout
                    + " is already attached to a RecyclerView:"
                    + layout.mRecyclerView.exceptionLabel());
        }
        mLayout.setRecyclerView(this);
        if (mIsAttached) {
            mLayout.dispatchAttachedToWindow(this);
        }
    }
    ...
}

但是有一个我不理解的原因，Logcat中打印的异常是：

UncaughtException: java.lang.IllegalStateException: View with id 2131231433: android.support.v7.widget.RecyclerView#onMeasure() did not set the measured dimension by calling setMeasuredDimension()`

也许有些东西捕获了这个异常，然后抛出另一个异常（没有原因）？

- Kevin Robatel

---

是的，需要重新初始化布局管理器。谢谢！ - Gurpreet Kaur

Answer 2

我通过调用 mRecyclerView.setLayoutManager(new LinearLayoutManager(this)); 来解决了这个问题，它起到了作用，希望能帮助到其他人。

- Zack

Answer 3

好的，正如@Kevin Robatel所提到的，我刚刚修复了它。在我的情况下，我只在onCreate()中初始化布局管理器，然后在多个地方使用它，例如onViewCreated()或onResume()。

所以，解决方法是每次需要设置布局管理器时重新初始化布局管理器。

这对我来说也是一个教训，干杯！

- Johnathan Awma

Answer 4

在我的情况下，我有多个RecyclerView，但我只创建了一次LinearLayoutManager。

我为每个RecyclerView创建了LinearLayoutManager，并且它起作用了。

谢谢。

- mehmoodnisar125