App crashes showing nullPointerException

Question

I was trying to make a basic intent from one activity to another but it crashes as soon as the button "next is clicked ".

    package com.example.aditya.myapplication;

    import android.content.Intent;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.Button;

    public class MainActivity extends AppCompatActivity {
        private Button next;
        @Override
        protected void onCreate(Bundle savedInstanceState) 
        {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            next = (Button) findViewById(R.id.toNextActivity1);
            next.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Intent i = new Intent(v.getContext(), qu1.class);
                    startActivity(i);
                }
            });
        }
    }

That's the java code . the activity_main.xml is this

<ImageView
    android:id="@+id/hello"
    android:layout_height="wrap_content"
    android:layout_width="wrap_content"
    android:src="@mipmap/ic_launcher"
    android:scaleType="center"
    android:layout_marginTop="104dp"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true">
</ImageView>

<Button
    android:id="@+id/toNextActivity1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="@color/colorAccent"
    android:text="Play "
    android:layout_marginBottom="79dp"
    android:layout_alignParentBottom="true"
    android:layout_toRightOf="@id/hello"
    android:layout_toEndOf="@id/hello" />

Logcat

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.aditya.myapplication/com.example.a‌ditya.myapplication.‌qu1}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.view.View.setOnClickListener(android.view.View$OnCli‌ckListener)' on a null object reference

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.aditya.myapplication/com.example.aditya.myapplication.qu1}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.view.View.setOnClickListener(android.view.View$OnClickListener)' on a null object reference — Robin staen, Mar 23 '17 at 09:54
Do you happen to have more than one instance of the layout (for different screen densities/sizes)? If so, you need to check them all to see if the button is there. — theblitz, Mar 23 '17 at 09:55
But the instances are for another activity, not this one #theblitz — Robin staen, Mar 23 '17 at 09:59

score 1 · Answer 1 · edited Mar 23 '17 at 09:49

1

Change v.getContext() to MainActivity.this

next.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent i = new Intent(MainActivity.this, qu1.class);
            startActivity(i);
        }
    });

edited Mar 23 '17 at 09:49

tahsinRupam

6,325
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answered Mar 23 '17 at 09:48

Komal12

3,340
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Does'nt help i've tried that – Robin staen Mar 23 '17 at 09:52
post your logcat...and add qu1 activity in your Manifest.xml – Komal12 Mar 23 '17 at 09:54
I've added it .. and logcat is in the question comments.. – Robin staen Mar 23 '17 at 09:55
Check your qu1 layout ...also comment Intent and add log on onClick and check log is printed or not – Komal12 Mar 23 '17 at 09:59

score 0 · Answer 2 · answered Mar 23 '17 at 10:00

0

Under the

    private Button next;

write

    Activity activity;

inside

    onCreate(){
    activity = this;

    }

then inside onClick

startActivity(new Intent(activity,qu1.class);

this shud solve your problem.

answered Mar 23 '17 at 10:00

shekhar g h

1,193
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It does'nt help .. – Robin staen Mar 23 '17 at 10:05
is qu1.class an activity ? – shekhar g h Mar 23 '17 at 10:15

score 0 · Answer 3 · answered Mar 23 '17 at 10:07

0

May be you donot have add qu1.class activity to the manifest file.
Change v.getContext to MainActivity.this

answered Mar 23 '17 at 10:07

Rabindra Acharya

1,868
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App crashes showing nullPointerException

3 Answers3