导航抽屉无法设置文本和图像

Question

Case_history_review.java

This is one of my java to use the nav bar

  Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    toolbar.setTitle("E-care");
    setSupportActionBar(toolbar);

    drawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);

    NavigationView view = (NavigationView) findViewById(R.id.navigation_view);
    view.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
        @Override
        public boolean onNavigationItemSelected(MenuItem menuItem) {
            Toast.makeText(Case_history_review.this, menuItem.getItemId() + " pressed", Toast.LENGTH_LONG).show();
            Log.d(R.id.nav_1+"", menuItem.getItemId() + " ");
            Intent intent = new Intent();
            switch (menuItem.getItemId())
            {

                case R.id.nav_1:
                    break;
                case R.id.nav_2:
                    intent.setClass(Case_history_review.this,queueshow.class);
                    //intent .putExtra("name", "Hello B Activity");
                    startActivity(intent);
                    break;
                case R.id.nav_3:
                    intent.setClass(Case_history_review.this,Appointmentcreate.class);
                    //intent .putExtra("name", "Hello B Activity");
                    startActivity(intent);
                    break;
                case R.id.nav_4:
                    intent.setClass(Case_history_review.this, AlarmActivity.class);
                    startActivity(intent);
                    break;
                case R.id.nav_5:

                    intent.setClass(Case_history_review.this, PatientReport.class);
                    startActivity(intent);
                    break;
                case R.id.nav_6:
                    intent.setClass(Case_history_review.this, TimeList.class);
                    startActivity(intent);
                    //logout
                    break;

            }
            menuItem.setChecked(true);
            drawerLayout.closeDrawers();
            return true;
        }
    });

    ActionBarDrawerToggle actionBarDrawerToggle = new ActionBarDrawerToggle( this, drawerLayout, toolbar, R.string.drawer_open , R.string.drawer_close){
        @Override
        public void onDrawerClosed(View drawerView) {
            super .onDrawerClosed(drawerView);
        }

        @Override
        public void onDrawerOpened(View drawerView) {
            super .onDrawerOpened(drawerView);
        }
    };
    db = new SQLiteHandler(getApplicationContext());
    HashMap<String, String> dbuser = db.getUserDetails();
    TextView name = (TextView) view.findViewById(R.id.drawer_name);
    String username = dbuser.get("name");
    Log.d("naem",username);
    name.setText(username);
    ImageLoader imageLoader = AppController.getInstance().getImageLoader();
    CirculaireNetworkImageView photo = (CirculaireNetworkImageView) view.findViewById(R.id.drawer_thumbnail);
    photo.setImageUrl("http://192.168.43.216/test/" + dbuser.get("image"), imageLoader);
    drawerLayout.setDrawerListener(actionBarDrawerToggle);
    actionBarDrawerToggle.syncState();

These two lines get errors

 name.setText(username);
 photo.setImageUrl("http://192.168.43.216/test/" + dbuser.get("image"), imageLoader);

Error message:

Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
                                                 at com.example.yuen.e_carei.Case_history_review.onCreate(Case_history_review.java:116)

layout/drawer_header.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="150dp"
android:background="#0097a7"
>

       <com.example.yuen.CirculaireNetworkImageView
    android:id="@+id/drawer_thumbnail"
    android:layout_width="70dp"
    android:layout_height="70dp"
    android:layout_marginRight="8dp"
    android:elevation="8dp"
    android:layout_above="@+id/drawer_name"
    android:layout_alignStart="@+id/drawer_name" />

<TextView
    android:id="@+id/drawer_name"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginLeft="24dp"
    android:layout_marginStart="24dp"
    android:layout_alignParentBottom="true"
    android:text="Eddard Stark"
    android:textSize="14sp"
    android:textColor="#fff"
    android:textStyle="bold"
    android:paddingBottom="8dp"
    />
 </RelativeLayout>

menu/drawer.xml

 <?xml version="1.0" encoding="utf-8"?>
 <menu xmlns:android="http://schemas.android.com/apk/res/android">
 <group android:checkableBehavior="single">
    <item
        android:id="@+id/nav_1"
        android:checked="true"
        android:icon="@drawable/hi"
        android:title="Case Review"/>
    <item
        android:id="@+id/nav_2"
        android:icon="@drawable/hi"
        android:title="Queue state"/>
    <item
        android:id="@+id/nav_3"
        android:icon="@drawable/hi"
        android:title="Create appointemnt"/>
    <item
        android:id="@+id/nav_4"
        android:icon="@drawable/hi"
        android:title="Alarm"/>
    <item
        android:id="@+id/nav_5"
        android:icon="@drawable/hi"
        android:title="Report"/>
    <item
        android:id="@+id/nav_6"
        android:icon="@drawable/hi"
        android:title="Logout"/>
 </group>
 </menu>

activity_case_history_solo.xml

<?xml version="1.0" encoding="utf-8"?>
 <android.support.design.widget.CoordinatorLayout       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:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context="com.example.yuen.e_carei.Case_history_review">

<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"
    android:fitsSystemWindows="true">

    <!-- your content layout -->
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        >

        <android.support.design.widget.AppBarLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:theme="@style/AppTheme.AppBarOverlay">

            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                android:background="?attr/colorPrimary"
                app:popupTheme="@style/AppTheme.PopupOverlay" />

        </android.support.design.widget.AppBarLayout>

        <RelativeLayout 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:layout_width="match_parent"
            android:layout_height="match_parent"
            app:layout_behavior="@string/appbar_scrolling_view_behavior"
            tools:context="com.example.yuen.e_carei.Case_history_review">

            <ImageView
                android:src="@drawable/hi"
                android:layout_width="100dp"
                android:layout_height="100dp"
                android:id="@+id/imageView2"
                android:layout_alignParentTop="true"
                android:layout_alignParentStart="true" />

            <RelativeLayout
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:layout_alignParentTop="true"
                android:layout_toEndOf="@+id/imageView2"
                android:layout_alignBottom="@+id/imageView2"
                android:id="@+id/relativeLayout">

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="Name : "
                    android:textSize="25sp"
                    android:id="@+id/textView2"
                    android:paddingTop="10dp"
                    android:paddingBottom="10dp"
                    android:paddingLeft="10dp"
                    android:layout_alignParentTop="true"
                    android:layout_alignParentStart="true" />

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="ID : "
                    android:textSize="25sp"
                    android:id="@+id/idTag"
                    android:paddingLeft="11dp"
                    android:layout_below="@+id/textView2"
                    android:layout_alignParentStart="true" />

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="Chan Tai Man"
                    android:textSize="25sp"
                    android:id="@+id/nameResult"
                    android:paddingBottom="10dp"
                    android:layout_above="@+id/idResult"
                    android:layout_toEndOf="@+id/textView2" />

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="N001"
                    android:textSize="25sp"
                    android:id="@+id/idResult"
                    android:layout_below="@+id/textView2"
                    android:layout_toEndOf="@+id/idTag" />
            </RelativeLayout>

            <ListView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/listView_case_history"
                android:layout_alignEnd="@+id/relativeLayout"
                android:layout_below="@+id/imageView2" />
        </RelativeLayout>
    </LinearLayout>

    <android.support.design.widget.NavigationView
        android:id="@+id/navigation_view"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        app:headerLayout="@layout/drawer_header"
        app:menu="@menu/drawer" />

</android.support.v4.widget.DrawerLayout>


<android.support.design.widget.FloatingActionButton
    android:id="@+id/fab"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="bottom|end"
    android:layout_margin="@dimen/fab_margin"
    android:src="@android:drawable/ic_dialog_email" />

  </android.support.design.widget.CoordinatorLayout>

I want to change the text in the drawer_header to become other string. However, it can get the id but crash in the runtime. Please give me some helps to solve this. Thank You.

Answer 1

Error depicts that the TextView object is null, means there is no such textview exists in the layout that is currently running.

Did the textview present in the XML layout that you are calling? Which layout did you put the TextView? Kindly check whether your activity is correct!!

The id that you use inside findViewById(R.id....) may be wrong. Double check that.

You have called the

TextView name = (TextView) view.findViewById(R.id.drawer_name);

in the Case_history_review.java but it seems that the above textView doesn't exists in your layout that you are calling. Probably you will be calling the below activity_case_history_solo.XML in the Activity and it doesn't has it. And the above TextView lies in the drawer_header.xml

Hope this helps you..!!