find a crash

[SilentSword2020]

android.support.v7.widget.LinearLayoutManager cannot be cast to android.support.v7.widget.StaggeredGridLayoutManager

XRefreshContentView:

public void getRecyclerViewInfo(LayoutManager layoutManager) {
int[] lastPositions = null;
if(this.layoutManagerType == null) {
if(layoutManager instanceof GridLayoutManager) {
this.layoutManagerType = XRefreshContentView.LAYOUT_MANAGER_TYPE.GRID;
} else if(layoutManager instanceof LinearLayoutManager) {
this.layoutManagerType = XRefreshContentView.LAYOUT_MANAGER_TYPE.LINEAR;
} else {
if(!(layoutManager instanceof StaggeredGridLayoutManager)) {
throw new RuntimeException("Unsupported LayoutManager used. Valid ones are LinearLayoutManager, GridLayoutManager and StaggeredGridLayoutManager");
}

            this.layoutManagerType = XRefreshContentView.LAYOUT_MANAGER_TYPE.STAGGERED_GRID;
        }
    }

    this.mTotalItemCount = layoutManager.getItemCount();
    switch(null.$SwitchMap$com$andview$refreshview$XRefreshContentView$LAYOUT_MANAGER_TYPE[this.layoutManagerType.ordinal()]) {
    case 1:
        this.mVisibleItemCount = layoutManager.getChildCount();
        this.mLastVisibleItemPosition = ((LinearLayoutManager)layoutManager).findLastVisibleItemPosition();

//TODO no break ?????????????????????????????????????????????????????????????
case 2:
this.mLastVisibleItemPosition = ((LinearLayoutManager)layoutManager).findLastVisibleItemPosition();
this.mFirstVisibleItem = ((LinearLayoutManager)layoutManager).findFirstVisibleItemPosition();
break;
case 3:
StaggeredGridLayoutManager staggeredGridLayoutManager = (StaggeredGridLayoutManager)layoutManager;
if(lastPositions == null) {
lastPositions = new int[staggeredGridLayoutManager.getSpanCount()];
}

        staggeredGridLayoutManager.findLastVisibleItemPositions(lastPositions);
        this.mLastVisibleItemPosition = this.findMax(lastPositions);
        staggeredGridLayoutManager.findFirstVisibleItemPositions(lastPositions);
        this.mFirstVisibleItem = this.findMin(lastPositions);
    }

}

[SilentSword2020]

java.lang.ClassCastException: android.support.v7.widget.LinearLayoutManager cannot be cast to android.support.v7.widget.StaggeredGridLayoutManager
at com.andview.refreshview.XRefreshContentView.getRecyclerViewInfo(XRefreshContentView.java:520)
at com.andview.refreshview.XRefreshContentView.onRecyclerViewScrolled(XRefreshContentView.java:158)
at com.andview.refreshview.XRefreshContentView$2.onScrolled(XRefreshContentView.java:225)
at android.support.v7.widget.RecyclerView.dispatchOnScrolled(RecyclerView.java:4618)
at android.support.v7.widget.RecyclerView.dispatchLayoutStep3(RecyclerView.java:3679)
at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:3323)
at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:3844)
at android.view.View.layout(View.java:17201)
at android.view.ViewGroup.layout(ViewGroup.java:5579)
at com.andview.refreshview.XRefreshView.onLayout(XRefreshView.java:365)
at android.view.View.layout(View.java:17201)
at android.view.ViewGroup.layout(ViewGroup.java:5579)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:396)
at android.widget.FrameLayout.onLayout(FrameLayout.java:333)
at android.view.View.layout(View.java:17201)
at android.view.ViewGroup.layout(ViewGroup.java:5579)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:396)
at android.widget.FrameLayout.onLayout(FrameLayout.java:333)
at android.view.View.layout(View.java:17201)
at android.view.ViewGroup.layout(ViewGroup.java:5579)
at android.support.v7.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:437)
at android.view.View.layout(View.java:17201)
at android.view.ViewGroup.layout(ViewGroup.java:5579)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:396)
at android.widget.FrameLayout.onLayout(FrameLayout.java:333)
at android.view.View.layout(View.java:17201)
at android.view.ViewGroup.layout(ViewGroup.java:5579)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:2001)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1844)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1753)
at android.view.View.layout(View.java:17201)
at android.view.ViewGroup.layout(ViewGroup.java:5579)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:396)
at android.widget.FrameLayout.onLayout(FrameLayout.java:333)
at com.android.internal.policy.PhoneWindow$DecorView.onLayout(PhoneWindow.java:2768)
at android.view.View.layout(View.java:17201)
at android.view.ViewGroup.layout(ViewGroup.java:5579)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2625)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2278)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1340)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6874)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:902)
at android.view.Choreographer.doCallbacks(Choreographer.java:704)
at android.view.Choreographer.doFrame(Choreographer.java:636)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:888)
at android.os.Handler.handleCallback(Handler.java:815)
at android.os.Handler.dispatchMessage(Handler.java:104)
at android.os.Looper.loop(Looper.java:207)
at android.app.ActivityThread.main(ActivityThread.java:5966)
at java.lang.reflect.Method.invoke(Method.java)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:679)

[SilentSword2020]

public void getRecyclerViewInfo(RecyclerView.LayoutManager layoutManager) {
int[] lastPositions = null;
if (layoutManagerType == null) {
if (layoutManager instanceof GridLayoutManager) {
layoutManagerType = LAYOUT_MANAGER_TYPE.GRID;
} else if (layoutManager instanceof LinearLayoutManager) {
layoutManagerType = LAYOUT_MANAGER_TYPE.LINEAR;
} else if (layoutManager instanceof StaggeredGridLayoutManager) {
layoutManagerType = LAYOUT_MANAGER_TYPE.STAGGERED_GRID;
} else {
throw new RuntimeException(
"Unsupported LayoutManager used. Valid ones are LinearLayoutManager, GridLayoutManager and StaggeredGridLayoutManager");
}
}
mTotalItemCount = layoutManager.getItemCount();
switch (layoutManagerType) {
case LINEAR:
mVisibleItemCount = layoutManager.getChildCount();
mLastVisibleItemPosition = ((LinearLayoutManager) layoutManager).findLastVisibleItemPosition();
case GRID:
//?????????????????????? LinearLayoutManager ?????
mLastVisibleItemPosition = ((LinearLayoutManager) layoutManager).findLastVisibleItemPosition();
mFirstVisibleItem = ((LinearLayoutManager) layoutManager).findFirstVisibleItemPosition();
break;
case STAGGERED_GRID:
StaggeredGridLayoutManager staggeredGridLayoutManager = (StaggeredGridLayoutManager) layoutManager;
if (lastPositions == null)
lastPositions = new int[staggeredGridLayoutManager.getSpanCount()];

            staggeredGridLayoutManager.findLastVisibleItemPositions(lastPositions);
            mLastVisibleItemPosition = findMax(lastPositions);

            staggeredGridLayoutManager
                    .findFirstVisibleItemPositions(lastPositions);
            mFirstVisibleItem = findMin(lastPositions);
            break;
    }
}

[huxq17]

GridLayoutManager extends LinearLayoutManager,所以会那么写，能给个有问题的demo么，没看懂为什么会出错。

[SilentSword2020]

之前指出的地方没有问题，可能导致崩溃原因和情景是
一个RecyclerView动态切换不同类型的layoutManager
由于代码里，缓存了layoutManagerType 值，没有同步更新 layoutManager对应的类型
layoutManagerType：如果不为空，没有去重新判断新的类型，使用旧的类型，和layoutManager不能一一对应