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社区首页 >问答首页 >为什么当我改变屏幕方向时会出现ClassNotFoundException？

问为什么当我改变屏幕方向时会出现ClassNotFoundException？
EN

Stack Overflow用户
提问于 2019-04-10 00:49:28
回答 1查看 1.5K关注 0票数 1

当我旋转我的设备时，我得到了ClassNotFoundException。该错误发生在我将admob库com.google.android.gms:play-services-ads:17.2.0添加到我的项目中之后。没有这个库，一切都很好。

我尝试将库版本更改为16.0.0，其中应用程序ID不是必需的，错误没有发生。

代码语言：javascript
复制
2019-04-09 19:32:16.164 12689-12718/com.example.example.myapplication E/Parcel: Class not found when unmarshalling: android.support.v4.app.FragmentManagerState
    java.lang.ClassNotFoundException: android.support.v4.app.FragmentManagerState
        at java.lang.Class.classForName(Native Method)
        at java.lang.Class.forName(Class.java:400)
        at android.os.Parcel.readParcelableCreator(Parcel.java:2564)
        at android.os.Parcel.readParcelable(Parcel.java:2518)
        at android.os.Parcel.readValue(Parcel.java:2421)
        at android.os.Parcel.readArrayMapInternal(Parcel.java:2788)
        at android.os.BaseBundle.unparcel(BaseBundle.java:271)
        at android.os.Bundle.getBundle(Bundle.java:817)
        at fw.onActivityCreated(:com.google.android.gms.dynamite_measurementdynamite@16089051@16.0.89 (040408-239467275):33)
        at com.google.android.gms.measurement.internal.AppMeasurementDynamiteService.onActivityCreated(:com.google.android.gms.dynamite_measurementdynamite@16089051@16.0.89 (040408-239467275):145)
        at cf.a(:com.google.android.gms.dynamite_measurementdynamite@16089051@16.0.89 (040408-239467275):160)
        at k.onTransact(:com.google.android.gms.dynamite_measurementdynamite@16089051@16.0.89 (040408-239467275):4)
        at android.os.Binder.transact(Binder.java:499)
        at com.google.android.gms.internal.measurement.zzq.zza(Unknown Source)
        at com.google.android.gms.internal.measurement.zzdp.onActivityCreated(Unknown Source)
        at com.google.android.gms.internal.measurement.zzex.zzgd(Unknown Source)
        at com.google.android.gms.internal.measurement.zzea$zzb.run(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
        at java.lang.Thread.run(Thread.java:760)
     Caused by: java.lang.ClassNotFoundException: android.support.v4.app.FragmentManagerState
        at java.lang.Class.classForName(Native Method)
        at java.lang.BootClassLoader.findClass(ClassLoader.java:1346)
        at java.lang.BootClassLoader.loadClass(ClassLoader.java:1406)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
        at java.lang.Class.classForName(Native Method) 
        at java.lang.Class.forName(Class.java:400) 
        at android.os.Parcel.readParcelableCreator(Parcel.java:2564) 
        at android.os.Parcel.readParcelable(Parcel.java:2518) 
        at android.os.Parcel.readValue(Parcel.java:2421) 
        at android.os.Parcel.readArrayMapInternal(Parcel.java:2788) 
        at android.os.BaseBundle.unparcel(BaseBundle.java:271) 
        at android.os.Bundle.getBundle(Bundle.java:817) 
        at fw.onActivityCreated(:com.google.android.gms.dynamite_measurementdynamite@16089051@16.0.89 (040408-239467275):33) 
        at com.google.android.gms.measurement.internal.AppMeasurementDynamiteService.onActivityCreated(:com.google.android.gms.dynamite_measurementdynamite@16089051@16.0.89 (040408-239467275):145) 
        at cf.a(:com.google.android.gms.dynamite_measurementdynamite@16089051@16.0.89 (040408-239467275):160) 
        at k.onTransact(:com.google.android.gms.dynamite_measurementdynamite@16089051@16.0.89 (040408-239467275):4) 
        at android.os.Binder.transact(Binder.java:499) 
        at com.google.android.gms.internal.measurement.zzq.zza(Unknown Source) 
        at com.google.android.gms.internal.measurement.zzdp.onActivityCreated(Unknown Source) 
        at com.google.android.gms.internal.measurement.zzex.zzgd(Unknown Source) 
        at com.google.android.gms.internal.measurement.zzea$zzb.run(Unknown Source) 
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133) 
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607) 
        at java.lang.Thread.run(Thread.java:760) 
     Caused by: java.lang.NoClassDefFoundError: Class not found using the boot class loader; no stack trace available

我的MainActivity.java是

代码语言：javascript
复制
public class MainActivity extends AppCompatActivity {
    final Fragment[] fragments = new Fragment[3];
    BottomNavigationView navView;
    FragmentManager fragmentManager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        MobileAds.initialize(this, "ca-app-pub-3940256099942544~3347511713");

        fragmentManager = getSupportFragmentManager();

        Toolbar toolbar = findViewById(R.id.toolbar);
        toolbar.setTitle(getString(R.string.app_name));
        toolbar.setTitleTextColor(Color.WHITE);
        toolbar.setNavigationIcon(R.drawable.ic_navigation);



        navView = findViewById(R.id.nav_view);


        AdView adView = findViewById(R.id.adView);
        adView.loadAd(new AdRequest.Builder().build());


        fragments[0] = new RandomFragment();
        fragments[1] = new FullListFragment();
        fragments[2] = new FavoriteFragment();

        fragmentManager.beginTransaction().add(R.id.main_container2, fragments[0]).commit();


        navView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {

            @Override
            public boolean onNavigationItemSelected(@NonNull MenuItem menuItem) {
                Fragment fragment;

                switch (menuItem.getItemId()) {
                    case R.id.navigation_home:
                        fragment = fragments[0];
                        break;

                    case R.id.navigation_dashboard:
                        fragment = fragments[1];
                        break;


                    case R.id.navigation_notifications:
                        fragment = fragments[2];
                        break;

                    default:
                        fragment = fragments[0];
                        break;
                }
                fragmentManager.beginTransaction().replace(R.id.main_container2, fragment).commit();
                return true;
            }
        });
        navView.setSelectedItemId(R.id.navigation_home);
    }


    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);

        outState.putInt("SelectedItemId", navView.getSelectedItemId());

    }


    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);
        int selectedItemId = savedInstanceState.getInt("SelectedItemId");
        navView.setSelectedItemId(selectedItemId);
    }


}
java
android
android-fragments
admob
EN

回答 1

Stack Overflow用户

回答已采纳

发布于 2019-06-24 00:14:21

经过长时间的思考。我有答案了。在新的库中添加了具有app id的ads初始化方法，该方法没有内部类SavedState。所以只需要像下面这样保存appid：

代码语言：javascript
复制
private static final String APP_ID = "your_app_id"

 @Override
    protected void onCreate(Bundle savedInstanceState) {
Bundle adsInstanceState = (savedInstanceState != null)
                ? savedInstanceState.getBundle(APP_ID): null;
        super.onCreate(adsInstanceState);
MobileAds.initialize(this,APP_ID);
}

  @Override
    protected void onSaveInstanceState(@NonNull Bundle outState) {
        super.onSaveInstanceState(outState);
        Bundle adsInstanceState = new Bundle();
        outState.putBundle(APP_ID, adsInstanceState )
   }

类似的问题，但与地图有关：https://stackoverflow.com/a/36818004/11334749希望这对某人有所帮助

票数 1
EN
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：

https://stackoverflow.com/questions/55597662

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