java.lang.IllegalArgumentException：观察者为null

发布时间：2020-12-14 05:31:23 所属栏目：Java 来源：网络整理

导读：我的一个应用程序的用户报告了此错误.我对如何解决它意味着什么感到困惑.经过一番谷歌搜索…依然没有运气.任何人以前看过这个或知道如何解决它？ java.lang.IllegalArgumentException: The observer is null.at android.database.Observable.unregisterObser

我的一个应用程序的用户报告了此错误.我对如何解决它意味着什么感到困惑.经过一番谷歌搜索…依然没有运气.任何人以前看过这个或知道如何解决它？

java.lang.IllegalArgumentException: The observer is null.
at android.database.Observable.unregisterObserver(Observable.java:59)
at android.widget.BaseAdapter.unregisterDataSetObserver(BaseAdapter.java:42)
at android.widget.HeaderViewListAdapter.unregisterDataSetObserver(HeaderViewListAdapter.java:256)
at android.widget.AbsListView.onDetachedFromWindow(AbsListView.java:2309)
at android.view.View.dispatchDetachedFromWindow(View.java:8197)
at android.view.ViewGroup.dispatchDetachedFromWindow(ViewGroup.java:1968)
at android.view.ViewGroup.dispatchDetachedFromWindow(ViewGroup.java:1966)
at android.view.ViewGroup.removeViewInternal(ViewGroup.java:3257)
at android.view.ViewGroup.removeViewInternal(ViewGroup.java:3237)
at android.view.ViewGroup.removeView(ViewGroup.java:3185)
at com.aheudev.a.slickdeals.adapters.DealPageAdapter.destroyItem(DealPageAdapter.java:174)
at android.support.v4.view.ViewPager.populate(ViewPager.java:415)
at android.support.v4.view.ViewPager.completeScroll(ViewPager.java:696)
at android.support.v4.view.ViewPager.computeScroll(ViewPager.java:668)
at android.view.ViewGroup.drawChild(ViewGroup.java:2434)
at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2189)
at android.view.View.draw(View.java:9282)
at android.view.ViewGroup.drawChild(ViewGroup.java:2584)
at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2189)
at android.view.ViewGroup.drawChild(ViewGroup.java:2582)
at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2189)
at android.view.ViewGroup.drawChild(ViewGroup.java:2582)
at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2189)
at android.view.View.draw(View.java:9282)
at android.widget.FrameLayout.draw(FrameLayout.java:419)
at com.android.internal.policy.impl.PhoneWindow$DecorView.draw(PhoneWindow.java:1923)
at android.view.ViewRoot.draw(ViewRoot.java:1695)
at android.view.ViewRoot.performTraversals(ViewRoot.java:1410)
at android.view.ViewRoot.handleMessage(ViewRoot.java:2040)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:132)
at android.app.ActivityThread.main(ActivityThread.java:4123)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:491)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599)
at dalvik.system.NativeStart.main(Native Method)

它来自我的PagerAdapter中的这个功能：

@Override
public void destroyItem(View collection,int position,Object view) {
    ((ViewPager) collection).removeView((View) view);
}

解决方法

我也有同样的问题,似乎您的DealPageAdapter上的unregisterDataSetObserver正在被调用两次.要解决这个问题,我覆盖了我的适配器中的unregisterDataSetObserver

@Override
public void unregisterDataSetObserver(DataSetObserver observer) {
    if (observer != null) {
        super.unregisterDataSetObserver(observer);
    }
}

希望这可以帮助！

（编辑：李大同）

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