在测试应用程序中，我正在尝试同步RecyclerView滚动。recycleview items但是，在水平滚动时，我遇到了一个问题，可能是由于缓存RecycleView，应用程序崩溃了。
public class TestActivty extends AppCompatActivity {
public static final String Tag = TestActivty.class.getName();
int mCurX = 0;
int countMainRecyleView = 0;
int countItemRecyleView = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.v_activty);
final RecyclerView mainRecyclerView = (RecyclerView) findViewById(R.id.activity_main);
final LinearLayoutManager verticalLinearLayoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);
mainRecyclerView.setLayoutManager(verticalLinearLayoutManager);
final LayoutInflater layoutInflater = LayoutInflater.from(this);
final RecyclerView.OnScrollListener masterOnScrollListener = new RecyclerView.OnScrollListener() {
RecyclerView masterRecyclerView = null;
RecyclerView.OnScrollListener scrollListener = this;
@Override
public void onScrollStateChanged(final RecyclerView recyclerView, final int newState) {
super.onScrollStateChanged(recyclerView, newState);
switch (newState) {
case RecyclerView.SCROLL_STATE_IDLE:
if (masterRecyclerView != null) {
masterRecyclerView = null;
final int firstVisibleItemPosition = verticalLinearLayoutManager.findFirstVisibleItemPosition();
final int lastVisibleItemPosition = verticalLinearLayoutManager.findLastVisibleItemPosition();
for (int i = firstVisibleItemPosition; i <= lastVisibleItemPosition; ++i) {
RecyclerView horizontalRecyclerView = (RecyclerView) mainRecyclerView.findViewHolderForAdapterPosition(i).itemView;
if (horizontalRecyclerView != recyclerView)
horizontalRecyclerView.addOnScrollListener(scrollListener);
}
}
break;
case RecyclerView.SCROLL_STATE_SETTLING:
case RecyclerView.SCROLL_STATE_DRAGGING:
if (masterRecyclerView == null) {
masterRecyclerView = recyclerView;
final int firstVisibleItemPosition = verticalLinearLayoutManager.findFirstVisibleItemPosition();
final int lastVisibleItemPosition = verticalLinearLayoutManager.findLastVisibleItemPosition();
for (int i = firstVisibleItemPosition; i <= lastVisibleItemPosition; ++i) {
RecyclerView horizontalRecyclerView = (RecyclerView) mainRecyclerView.findViewHolderForAdapterPosition(i).itemView;
if (horizontalRecyclerView != recyclerView)
horizontalRecyclerView.removeOnScrollListener(scrollListener);
}
}
}
}
@Override
public void onScrolled(final RecyclerView recyclerView, final int dx, final int dy) {
super.onScrolled(recyclerView, dx, dy);
mCurX += dx;
int firstVisibleItemPosition = verticalLinearLayoutManager.findFirstVisibleItemPosition();
int lastVisibleItemPosition = verticalLinearLayoutManager.findLastVisibleItemPosition();
for (int i = firstVisibleItemPosition; i <= lastVisibleItemPosition; ++i) {
RecyclerView horizontalRecyclerView = (RecyclerView) mainRecyclerView.findViewHolderForAdapterPosition(i).itemView;
if (horizontalRecyclerView != recyclerView)
horizontalRecyclerView.scrollBy(dx, dy);
horizontalRecyclerView.getRecycledViewPool().clear();
}
}
};
mainRecyclerView.setAdapter(new RecyclerView.Adapter() {
@Override
public RecyclerView.ViewHolder onCreateViewHolder(final ViewGroup parent, final int viewType) {
RecyclerView horizontalRecyclerView = (RecyclerView) layoutInflater.inflate(R.layout.horizontal_recycler_view, parent, false);
horizontalRecyclerView.setLayoutManager(new LinearLayoutManager(TestActivty.this, LinearLayoutManager.HORIZONTAL, false));
horizontalRecyclerView.addOnScrollListener(masterOnScrollListener);
final RecyclerView.ViewHolder horizontalViewHolder = new RecyclerView.ViewHolder(horizontalRecyclerView) {
};
horizontalRecyclerView.setAdapter(new RecyclerView.Adapter() {
@Override
public RecyclerView.ViewHolder onCreateViewHolder(final ViewGroup parent, final int viewType) {
return new RecyclerView.ViewHolder(layoutInflater.inflate(R.layout.single_item, parent, false)) {
};
}
@Override
public void onBindViewHolder(final RecyclerView.ViewHolder holder, final int position) {
((TextView) holder.itemView).setText("horizontalRecyclerView:" + horizontalViewHolder.getAdapterPosition() + "\nitem:" + position);
}
@Override
public int getItemCount() {
return 50;
}
});
return horizontalViewHolder;
}
@Override
public void onBindViewHolder(final RecyclerView.ViewHolder holder, final int position) {
RecyclerView recyclerView = (RecyclerView) holder.itemView;
recyclerView.removeOnScrollListener(masterOnScrollListener);
recyclerView.scrollToPosition(0);
recyclerView.scrollBy(mCurX,0);
recyclerView.addOnScrollListener(masterOnScrollListener);
recyclerView.getAdapter().notifyDataSetChanged();
}
@Override
public int getItemCount() {
return 105;
}
});
}
}
v_activities.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.RecyclerView
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</RelativeLayout>
horizontal_recycler_view.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.RecyclerView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
单个项目.xml
<?xml version="1.0" encoding="utf-8"?>
<TextView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:gravity="center"
android:orientation="vertical"
android:padding="10dp"/>
错误日志
java.lang.NullPointerException: Attempt to read from field 'android.view.View android.support.v7.widget.RecyclerView$ViewHolder.itemView' on a null object reference
at verjnakan.TestActivty$1.onScrolled(TestActivty.java:80)
at android.support.v7.widget.RecyclerView.dispatchOnScrolled(RecyclerView.java:3954)
at android.support.v7.widget.RecyclerView.dispatchLayoutStep3(RecyclerView.java:3115)
at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:2917)
at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:3283)
at android.view.View.layout(View.java:16711)
at android.view.ViewGroup.layout(ViewGroup.java:5328)
at android.support.v7.widget.RecyclerView$LayoutManager.layoutDecorated(RecyclerView.java:7650)
at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1448)
at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1353)
at android.support.v7.widget.LinearLayoutManager.scrollBy(LinearLayoutManager.java:1180)
at android.support.v7.widget.LinearLayoutManager.scrollVerticallyBy(LinearLayoutManager.java:1031)
at android.support.v7.widget.RecyclerView$ViewFlinger.run(RecyclerView.java:4061)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:777)
at android.view.Choreographer.doCallbacks(Choreographer.java:590)
at android.view.Choreographer.doFrame(Choreographer.java:559)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:763)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:5942)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)
+++++++++++++++++++++++++++++
D/Error: ERR: stack=java.lang.StackOverflowError: stack size 8MB
at android.view.View.invalidateInternal(View.java:12678)
at android.view.View.invalidate(View.java:12668)
at android.view.View.invalidateViewProperty(View.java:12788)
at android.view.View.offsetLeftAndRight(View.java:12299)
at android.support.v7.widget.RecyclerView.offsetChildrenHorizontal(RecyclerView.java:3888)
at android.support.v7.widget.RecyclerView$LayoutManager.offsetChildrenHorizontal(RecyclerView.java:7228)
at android.support.v7.widget.OrientationHelper$1.offsetChildren(OrientationHelper.java:229)
at android.support.v7.widget.LinearLayoutManager.scrollBy(LinearLayoutManager.java:1189)
at android.support.v7.widget.LinearLayoutManager.scrollHorizontallyBy(LinearLayoutManager.java:1019)
at android.support.v7.widget.RecyclerView.scrollByInternal(RecyclerView.java:1525)
at android.support.v7.widget.RecyclerView.scrollBy(RecyclerView.java:1436)
at verjnakan.TestActivty$1.onScrolled(TestActivty.java:95)
at android.support.v7.widget.RecyclerView.dispatchOnScrolled(RecyclerView.java:3954)
at android.support.v7.widget.RecyclerView.scrollByInternal(RecyclerView.java:1557)
at android.support.v7.widget.RecyclerView.scrollBy(RecyclerView.java:1436)
at verjnakan.TestActivty$1.onScrolled(TestActivty.java:95)
at android.support.v7.widget.RecyclerView.dispatchOnScrolled(RecyclerView.java:3954)
at android.support.v7.widget.RecyclerView.scrollByInternal(RecyclerView.java:1557)
at android.support.v7.widget.RecyclerView.scrollBy(RecyclerView.java:1436)
at verjnakan.TestActivty$1.onScrolled(TestActivty.java:95)
at android.support.v7.widget.RecyclerView.dispatchOnScrolled(RecyclerView.java:3954)
at android.support.v7.widget.RecyclerView.scrollByInternal(RecyclerView.java:1557)
at android.support.v7.widget.RecyclerView.scrollBy(RecyclerView.java:1436)
at verjnakan.TestActivty$1.onScrolled(TestActivty.java:95)
at android.support.v7.widget.RecyclerView.dispatchOnScrolled(RecyclerView.java:3954)
at android.support.v7.widget.RecyclerView.scrollByInternal(RecyclerView.java:1557)
at android.support.v7.widget.RecyclerView.scrollBy(RecyclerView.java:1436)
at verjnakan.TestActivty$1.onScrolled(TestActivty.java:95)
at android.support.v7.widget.RecyclerView.dispatchOnScrolled(RecyclerView.java:3954)
at android.support.v7.widget.RecyclerView.scrollByInternal(RecyclerView.java:1557)
at android.support.v7.widget.RecyclerView.scrollBy(RecyclerView.java:1436)
at verjnakan.TestActivty$1.onScrolled(TestActivty.java:95)
at android.support.v7.widget.RecyclerView.dispatchOnScrolled(RecyclerView.java:3954)
at android.support.v7.widget.RecyclerView.scrollByInternal(RecyclerView.java:1557)
at android.support.v7.widget.RecyclerView.scrollBy(RecyclerView.java:1436)
at verjnakan.TestActivty$1.onScrolled(TestActivty.java:95)
at android.support.v7.widget.RecyclerView.dispatchOnScrolled(RecyclerView.java:3954)
at android.support.v7.widget.RecyclerView.scrollByInternal(RecyclerView.java:1557)
at android.support.v7.widget.RecyclerView.scrollBy(RecyclerView.java:1436)
at verjnakan.TestActivty$1.onScrolled(TestActivty.java:95)
at android.support.v7.widget.RecyclerView.dispatchOnScrolled(RecyclerView.java:3954)
at android.support.v7.widget.RecyclerView.scrollByInternal(RecyclerView.java:1557)
at android.support.v7.widget.RecyclerView.scrollBy(RecyclerView.java:1436)
at verjnakan.TestActivty$1.onScrolled(TestActivty.java:95)
at android.support.v7.widget.RecyclerView.dispatchOnScrolled(RecyclerView.java:3954)
at android.support.v7.widget.RecyclerView.scrollByInternal(RecyclerView.java:1557)
at android.support.v7.widget.RecyclerView.scrollBy(RecyclerView.java:1436)
at verjnakan.TestActivty$1.onScrolled(TestActivty.java:95)
at android.support.v7.widget.RecyclerView.dispatchOnScrolled(RecyclerView.java:3954)
at android.support.v7.widget.RecyclerView.scrollByInternal(RecyclerView.java:1557)
at android.support.v7.widget.RecyclerView.scrollBy(RecyclerView.java:1436)
at verjnakan.TestActivty$1.onScrolled(TestActivty.java:95)
at android.sup..
您似乎有一个以调用堆栈溢出结束的无限循环。机制是这样的：
onScrolled()scrollBy()onScrolled()scrollBy()更改滚动逻辑。