问androidx.appcompat.widget上的空引用

EN

Attempt to invoke virtual method 'void androidx.appcompat.widget.ContentFrameLayout.setId(int)' on a null object reference
        at androidx.appcompat.app.AppCompatDelegateImpl.createSubDecor(AppCompatDelegateImpl.java:1000)
        at androidx.appcompat.app.AppCompatDelegateImpl.ensureSubDecor(AppCompatDelegateImpl.java:815)
        at androidx.appcompat.app.AppCompatDelegateImpl.setContentView(AppCompatDelegateImpl.java:703)
        at androidx.appcompat.app.AppCompatActivity.setContentView(AppCompatActivity.java:195)
        at com.me.recyclerview.MainActivity.onCreate

@Override
    protected void onCreate(Bundle savedInstanceState) {
   
        super.onCreate(savedInstanceState);
        

     

       if (ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
                    ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, 1);
    
                } else {
    
                   
                    showAll()
    
    
    
                }
}
    
       
 public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);

        switch (requestCode){
            case 1:
                if(grantResults.length>0&&grantResults[0]==PackageManager.PERMISSION_GRANTED){
                    Toast.makeText(MainActivity.this,"permission 1 granted",Toast.LENGTH_LONG).show();
                    if(ContextCompat.checkSelfPermission(MainActivity.this,Manifest.permission.WRITE_EXTERNAL_STORAGE)!= PackageManager.PERMISSION_GRANTED){
                        showAll();
                    }
}




public void showAll(){
       
        setContentView(R.layout.activity_main);
        getWindow().getDecorView().setSystemUiVisibility(View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR);

        toolbarInitialize();
        initialize();
          
        

    }

<?xml version="1.0" encoding="utf-8"?>
<androidx.drawerlayout.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/DrawerLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:openDrawer="left"
android:fillViewport="false"
android:fitsSystemWindows="true"
tools:context=".MainActivity">


    <LinearLayout

        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:orientation="vertical"


        >

        <include
            android:id="@+id/include_toolbar"
            layout="@layout/custom_toolbar"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:transitionName="transitionToolbar"
            />
        <com.google.android.material.tabs.TabLayout
            android:id="@+id/TabLayout"
            style="@style/mytab"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:minHeight="?attr/actionBarSize"
            app:tabIndicatorColor="#E5F1EF"
            app:tabMode="scrollable"
            app:tabTextColor="@android:color/black"
            android:transitionName="transitionTabLayout"

            >



            <com.google.android.material.tabs.TabItem
                android:id="@+id/Videos"


                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Videos" />

        </com.google.android.material.tabs.TabLayout>

        <androidx.viewpager.widget.ViewPager
            android:id="@+id/Viewpager"
            android:layout_width="match_parent"
            android:layout_height="match_parent">

        </androidx.viewpager.widget.ViewPager>



    </LinearLayout>


<com.google.android.material.navigation.NavigationView
    android:id="@+id/mainNav"
    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:layout_gravity="start"
    android:fitsSystemWindows="true"
    app:headerLayout="@layout/navigation_drawer_layout"

    />

</androidx.drawerlayout.widget.DrawerLayout>