View becomes null on setText

Question

I have a custom ViewGroup that instantiates a private TextView text1 in a the init() method called by the View constructor.

I get a NullPointerException when I'm trying to setText(...), on line 335, even though I specifically check that it's not null before:

//also tried instantiating here with text1 = new TextView(this.getContext());
private TextView text1;


public SlidingTextView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();//line 65
    }

private void init() {
   ...
   //instantiate here 
   text1 = new TextView(this.getContext());

   //other setters on text1
   text1.setTextSize(fontSize);
   text1.setTextColor(Color.WHITE);
   text1.setPadding(textPadding, 0, textPadding, 0);
   text1.setGravity(Gravity.CENTER);
   text1.setWidth(textWidth);
   text1.setMaxLines(1);
   text1.setEllipsize(TextUtils.TruncateAt.END);
   text1.setMaxWidth(textWidth);
   text1.setBackgroundColor(Color.TRANSPARENT);
   text1.measure(0, textHeight);

   // Logs: android.widget.TextView@41b04b60 false
   Log.d("", text1.toString() + " " + (text1 == null));
   // Throws NullPointerException
   text1.setText("Text");//Line 335
...
}

Here's the logcat:

07-23 12:51:11.433: E/AndroidRuntime(31419): FATAL EXCEPTION: main
07-23 12:51:11.433: E/AndroidRuntime(31419): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.app/com.example.app.MainActivity}: android.view.InflateException: Binary XML file line #71: Error inflating class com.example.app.SlidingTextView
07-23 12:51:11.433: E/AndroidRuntime(31419):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2110)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2135)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at android.app.ActivityThread.access$700(ActivityThread.java:140)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1237)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at android.os.Handler.dispatchMessage(Handler.java:99)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at android.os.Looper.loop(Looper.java:137)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at android.app.ActivityThread.main(ActivityThread.java:4921)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at java.lang.reflect.Method.invokeNative(Native Method)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at java.lang.reflect.Method.invoke(Method.java:511)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1027)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:794)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at dalvik.system.NativeStart.main(Native Method)
07-23 12:51:11.433: E/AndroidRuntime(31419): Caused by: android.view.InflateException: Binary XML file line #71: Error inflating class com.example.app.SlidingTextView
07-23 12:51:11.433: E/AndroidRuntime(31419):    at android.view.LayoutInflater.createView(LayoutInflater.java:613)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:687)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at android.view.LayoutInflater.rInflate(LayoutInflater.java:746)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at android.view.LayoutInflater.inflate(LayoutInflater.java:489)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at android.view.LayoutInflater.inflate(LayoutInflater.java:396)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at android.view.LayoutInflater.inflate(LayoutInflater.java:352)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:313)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at android.app.Activity.setContentView(Activity.java:1924)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at com.example.app.MainActivity.onCreate(MainActivity.java:101)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at android.app.Activity.performCreate(Activity.java:5206)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2074)
07-23 12:51:11.433: E/AndroidRuntime(31419):    ... 11 more
07-23 12:51:11.433: E/AndroidRuntime(31419): Caused by: java.lang.reflect.InvocationTargetException
07-23 12:51:11.433: E/AndroidRuntime(31419):    at java.lang.reflect.Constructor.constructNative(Native Method)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at java.lang.reflect.Constructor.newInstance(Constructor.java:417)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at android.view.LayoutInflater.createView(LayoutInflater.java:587)
07-23 12:51:11.433: E/AndroidRuntime(31419):    ... 22 more
07-23 12:51:11.433: E/AndroidRuntime(31419): Caused by: java.lang.NullPointerException
07-23 12:51:11.433: E/AndroidRuntime(31419):    at android.widget.TextView.checkForRelayout(TextView.java:6600)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at android.widget.TextView.setText(TextView.java:3732)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at android.widget.TextView.setText(TextView.java:3590)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at android.widget.TextView.setText(TextView.java:3565)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at com.example.app.SlidingTextView.init(SlidingTextView.java:335)
07-23 12:51:11.433: E/AndroidRuntime(31419):    at com.example.app.SlidingTextView.<init>(SlidingTextView.java:65)
07-23 12:51:11.433: E/AndroidRuntime(31419):    ... 25 more

Any ideas what might be the cause of this?

UPDATE1:

textWidth=500;
textHeight=0;
textPadding=10;
fontSize=30;

All variables and values checked before setting setText() , not null and returning proper values

UPDATE2: main.xml:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/root"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="@drawable/background_gradient"
    tools:context="com.example.app.MainActivity" >
  <LinearLayout
        android:id="@+id/footer"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:gravity="center"
        android:orientation="horizontal"
        android:paddingBottom="10dp"
        android:paddingTop="10dp" >

        <ImageView
            android:id="@+id/message"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginRight="10dp"
            android:src="@drawable/message_btn" />

        <ImageView
            android:id="@+id/start"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@drawable/start_btn" />

        <ImageView
            android:id="@+id/call"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="10dp"
            android:src="@drawable/call_btn" />
  </LinearLayout>
  <com.example.app.SlidingTextView
        android:id="@+id/text"
        android:layout_width="match_parent"
        android:layout_height="30dp"
        android:layout_above="@id/footer" />    



</RelativeLayout>

MainActivity.java:

public class MainActivity extends Activity {
    private int height;
    private int width;
    private Display display;

    private RelativeLayout rootContainer;
    private SlidingTextView slidingTextView;

protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

}

I removed as much code as possible for testing. The problem remains.

Update3:

The problem seems to be: text1.measure(0,textHeight). Although textHeight=0, it doesn't matter, I tried with different values.

It also seems to happen only when text1.measure(...) is called after the other setters:

// No NullPointerException
text1.measure(0,textHeight);

// The other setters
text1.setTextSize(fontSize);
text1.setTextColor(Color.WHITE);
text1.setPadding(textPadding, 0, textPadding, 0);
text1.setGravity(Gravity.CENTER);
text1.setWidth(textWidth);
text1.setMaxLines(1);
text1.setEllipsize(TextUtils.TruncateAt.END);
text1.setMaxWidth(textWidth);
text1.setBackgroundColor(Color.TRANSPARENT);

// Throws NullPointerException
text1.measure(0,textHeight);

Can someone explain why? Probably because the text value of text1 is "" (never set, no call to setText(...) before), so after calling one of the setters, text1s text it is set null or something of the kind. I will try to circumvent the measure(...), but it would be nice to get an explanation. Thank you!

you are getting Caused by: android.view.InflateException: Binary XML file line #71: Error inflating class com.example.app.SlidingTextView error as well... frst try to resolve that, your nullPointerException will automatically get solved. — androidStud, Jul 23 '14 at 10:56
Post your full class for full clarification as text1 = new TextView(this.getContext());//here context will be valid only if its an Activity class or else you can do as private void init(Context context) { ... //instantiate here text1 = new TextView(context); ... rest your code. — MOSO, Jul 23 '14 at 11:44
@ androidStud If you look down the error stack you can see that the reason the xml fails to inflate is because of the NullPointerException — fregos23, Jul 23 '14 at 12:19
@MOSO The context is valid, it's passed from the main activity through the view constructor. I checked the context for validity. — fregos23, Jul 23 '14 at 12:23
@Apoorv The rest of the class is irrelevant, I can confirm the error with just the code above, I removed all the other code and the error remains. It must be in the lines above. Updated with the values of variables used. — fregos23, Jul 23 '14 at 12:24

score 1 · Accepted Answer · edited May 23 '17 at 12:22

1

The problem is not in setText() but in the Android source code in function checkForRelayout so my guess is that the answer lies in NullPointerException at TextView.checkForRelayout() while setText()

where it is stated that the problem is that the textView does not have layoutParams:

vh.tv.setLayoutParams(new ViewGroup.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));

edited May 23 '17 at 12:22

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answered Jul 23 '14 at 12:51

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View becomes null on setText

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