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我收到以下错误DrawerLayout而其中有android.support.design.widget.NavigationView为drawerlayout NULL异常时xamarin安卓
System.NullReferenceException相同的活动增加RecyclerView加入recyclerview未设置为一个对象
这里的一个实例是我的C#代码
DrawerLayout drawerLayout;
protected override void OnCreate(Bundle savedInstanceState)
{
base.OnCreate(savedInstanceState);
drawerLayout = this.FindViewById<DrawerLayout>(Resource.Id.drawer_layout);
drawerLayout.CloseDrawers();
}
这里是我的axml文件代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.AppBarLayout
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:id="@+id/toolbar_layout">
<include
android:id="@+id/toolbar"
layout="@layout/toolbar"
app:layout_scrollFlags="scroll|enterAlways" />
</android.support.design.widget.AppBarLayout>
</RelativeLayout>
<android.support.design.widget.NavigationView
android:id="@+id/nav_view"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
app:headerLayout="@layout/nav_header"
app:menu="@menu/nav_menu" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:background="#e7e6e6"
android:paddingTop="60dp">
<android.support.v7.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scrollbars="vertical" />
</LinearLayout>
如果我会删除下列从axml代码,然后它会正常工作。我不知道为什么当我在我的xml文件中添加android.support.v7.widget.RecyclerView时DrawerLayout变为NULL?
<android.support.v7.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scrollbars="vertical" />