Attempt to invoke virtual method 'void android.view.View.measure(int, int)' on a null object reference

Question

I am trying to use

library to take screenshot.

But it gives error.

Attempt to invoke virtual method 'void android.view.View.measure(int, int)' on a null object reference

Relativelayout:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:ads="http://schemas.android.com/apk/res-auto"
    tools:context="x.y.z"
    android:orientation="vertical"
    android:id="@+id/layoutview">

    <!--
    <com.google.android.gms.ads.AdView
        android:id="@+id/adViewChat2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_alignParentTop="true"
        ads:adSize="SMART_BANNER"
        ads:adUnitId="x">
    </com.google.android.gms.ads.AdView>


-->

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="English"
        android:background="@drawable/shape"
        android:textAppearance="?android:attr/textAppearanceMedium"

        android:layout_marginLeft="@dimen/_15sdp"
        android:layout_marginRight="@dimen/_15sdp"
        android:textAlignment="center"

        android:id="@+id/textviewtop"
        android:layout_marginTop="@dimen/_5sdp"
        android:textColor="#ffffff"
        android:textStyle="bold"


        />




    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/scrollView"
        android:orientation="vertical"
        android:layout_above="@+id/linear"
        android:layout_marginBottom="@dimen/_5sdp"
        android:layout_below="@+id/textviewtop"
        android:layout_marginTop="@dimen/_5sdp"
        >
        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:paddingLeft="@dimen/_15sdp"
            android:background="@drawable/shape"

            android:layout_marginLeft="@dimen/_15sdp"
            android:layout_marginRight="@dimen/_15sdp"
            >

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:textAppearance="?android:attr/textAppearanceMedium"
                android:text="@string/welcome"
                android:id="@+id/textView"
                android:textColor="#ffffff"/>

        </RelativeLayout>

    </ScrollView>


    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:layout_alignParentBottom="true"
        android:layout_marginLeft="@dimen/_15sdp"
        android:layout_marginRight="@dimen/_15sdp"
        android:background="@drawable/shape"
        android:id="@+id/linear">



        <EditText
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/editText2"
            android:textColor="#ffffff"
            android:layout_weight="0.9"
            android:hint="Write a message"
            android:textColorHint="#A4A4A4"/>

        <Button
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:text="send"
            android:id="@+id/btn_send"
            android:layout_weight="0.1"
            android:textColor="#ffffff"

            />

    </LinearLayout>



</RelativeLayout>

in OnCreate Method:

setContentView(R.layout.activity_main);
View myView =(RelativeLayout) findViewById(R.id.layoutview);
Bitmap bitmap_view = 
    ScreenShott.getInstance().takeScreenShotOfView(myView); // problematic line, this line gives the error.

How can I solve my problem? How can I get relative layout view?

try replacing findViewById(R.id.layoutview); with findViewById(R.layout.layoutView); — Shreemaan Abhishek, Aug 08 '20 at 11:41
Can you post the full stacktrace? It's hard to tell what's wrong without it. — Eugen Pechanec, Aug 17 '20 at 05:26
Try debugging and see if `myView` is null or not. If it is null, then it either does not exist in your layout, or, something is happening inside the library that I cannot quite tell without you posting the stack trace. — Furkan Yurdakul, Aug 17 '20 at 08:49

score 0 · Answer 1 · answered Aug 10 '20 at 14:35

You must don't it in onCreate. In this onCreate method, your layout is measured and inflated but your UI is not yet created.

You must call your code later than onCreate. for example in a button event:

Button capture_screenshot = findViewById(R.id.button_takeshoot);
        capture_screenshot.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                View myView =(RelativeLayout) findViewById(R.id.layoutview);
                Bitmap bitmap_view = ScreenShott.getInstance().takeScreenShotOfView(myView);
            }
        });

check Activity Lifecycle

What do you mean by "layout measured", "layout inflated", "UI not created"? UI is defined by layout, it's created when layout is created. Views are inflated by `setContentView`. But it's *not* measured immediately. The order is important. — Eugen Pechanec, Aug 16 '20 at 20:07

score 0 · Answer 2 · answered Aug 11 '20 at 16:44

You need to take a screenshot after view drawing so you need a listener when view drawing is done you can use ViewTreeObserver.OnGlobalLayoutListener

    ViewTreeObserver observer  = view.getViewTreeObserver();
    observer .addOnGlobalLayoutListener (new ViewTreeObserver.OnGlobalLayoutListener() {
        @Override
        public void onGlobalLayout() {
            Bitmap bitmap_view = ScreenShott.getInstance().takeScreenShotOfView(view);

            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
                view.getViewTreeObserver().removeOnGlobalLayoutListener(this);
            } else {
                view.getViewTreeObserver() .removeGlobalOnLayoutListener(this);
            }
        }
    });

symbol 'view' is the name of my view but in your code put your view name for example 'myView' — AmrDeveloper, Aug 13 '20 at 16:32

score 0 · Answer 3 · answered Aug 15 '20 at 16:24

This wont give you NPE but SS:

Kotlin:

override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        Log.d(TAG, "onCreate: this method invoke")
        setContentView(R.layout.activity_main_ss)

        val rootView = window.decorView.rootView
        Log.d(TAG, "onCreate: rootView$rootView")

        val bitmap = ScreenShott.getInstance().takeScreenShotOfJustView(rootView)
    }

Java:

@Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_ss);

        View rootView = findViewById(android.R.id.content).getRootView();
        Bitmap bitmap = ScreenShott.getInstance().takeScreenShotOfJustView(rootView);
    }

P.S: I have used the same lib as mentioned above and not getting NPE

You're using `takeScreenShotOfJustView` what's the difference from `takeScreenShotOfView` in question? — Eugen Pechanec, Aug 17 '20 at 05:27

score 0 · Answer 4 · answered Aug 17 '20 at 09:20

0

You can try .takeScreenShotOfJustView(view) instead of .takeScreenShotOfView(view) So, use

Bitmap bitmap_view = 
    ScreenShott.getInstance().takeScreenShotOfJustView(myView);

This will take the screenshot without constraints...

answered Aug 17 '20 at 09:20

M.AQIB

359
5
11

score -1 · Answer 5 · edited Aug 08 '20 at 16:47

-1

please write like this RelativeLayout myView = findViewById(R.id.layoutview); hoping that the name of the xml layout file is activity_main.xml

edited Aug 08 '20 at 16:47

Tamir Abutbul

7,301
7
25
53

answered Aug 08 '20 at 14:04

paule mandengue

64
5

The result is the same in both cases because the function call is the same in both cases: `findViewById(R.id.layoutview)`. Casting to `RelativeLayout` and then back to `View` is ugly, yes, but otherwise does nothing. This should have been a comment promoting code readability instead. – Eugen Pechanec Aug 18 '20 at 09:17

Attempt to invoke virtual method 'void android.view.View.measure(int, int)' on a null object reference

5 Answers5