下面是我在使用导航抽屉导航时在Android Studio中获得的错误的StackTrace.这是一个新错误,因为它之前没有发生过.所以我不确定如果我改变了什么.
08-11 23:16:37.823 15951-15951/com.example.aids.a09application
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.aids.a09application, PID: 15951
java.lang.NullPointerException: Attempt to read from field 'int android.support.v4.app.Fragment.mContainerId' on a null object reference
at android.support.v4.app.FragmentTransition.addToFirstInLastOut(FragmentTransition.java:1017)
at android.support.v4.app.FragmentTransition.calculateFragments(FragmentTransition.java:976)
at android.support.v4.app.FragmentTransition.startTransitions(FragmentTransition.java:95)
at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2146)
at android.support.v4.app.FragmentManagerImpl.optimizeAndExecuteOps(FragmentManager.java:2103)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2013)
at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:710)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6692)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1468)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1358)
下面是Java类,我的导航抽屉有片段交易.
public class MainActivity extends AppCompatActivity {
DrawerLayout drawerLayout;
Toolbar toolbar;
ActionBarDrawerToggle actionBarDrawerToggle;
FragmentTransaction fragmentTransaction;
NavigationView navigationView;
Intent intent;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) …