Null object reference on setText in Android app

Question

My app crashes on this setText here. I think probably because it cannot find the id so I looked into to R.java and found the id there. I'm confused why it still crashes.

TextView city = (TextView)findViewById(R.id.city_result);
city.setText(msg[0]);

R.java

public static final int city_result=0x7f080041;

and this code is in the public static final class id method.

Any help will be appreciated! Thanks!!

================ More Code:

 protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_weather_report);
    if (savedInstanceState == null) {
        getSupportFragmentManager().beginTransaction()
                .add(R.id.container, new PlaceholderFragment())
                .commit();
    }

    //get message from intent
    Intent intent = getIntent();
    String[] message = intent.getStringArrayExtra(MainActivity.EXTRA_MESSAGE);
    setResult(message);
}
public void setResult(String[] msg)
    {
        //test
        TextView city = (TextView)findViewById(R.id.city_result);
        city.setText(msg[0]);
    }

This file I just started, elsewhere is just system generated new file code, I didn't edit yet. Here's logcat:

    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.chen.weather/com.example.chen.weather.WeatherReport}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
            at android.app.ActivityThread.access$800(ActivityThread.java:144)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
     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.chen.weather.WeatherReport.setResult(WeatherReport.java:78)
            at com.example.chen.weather.WeatherReport.onCreate(WeatherReport.java:32)
            at android.app.Activity.performCreate(Activity.java:5933)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
                at android.app.ActivityThread.access$800(ActivityThread.java:144)
                at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
                at android.os.Handler.dispatchMessage(Handler.java:102)
                at android.os.Looper.loop(Looper.java:135)
                at android.app.ActivityThread.main(ActivityThread.java:5221)
                at java.lang.reflect.Method.invoke(Native Method)
                at java.lang.reflect.Method.invoke(Method.java:372)
                at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
                at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)

show more code where `TextView city = (TextView)findViewById(R.id.city_result);` line is used — ρяσѕρєя K, Jan 31 '15 at 04:44
"_My app crashes_" doesn't mean much on it's own. Post logcat output, indicate the line of code producing the error/exception, show us `msg` and how it is created and populated .... — takendarkk, Jan 31 '15 at 04:49
@ρяσѕρєяK I just started and this is the only place where textview shows up. — Zip, Jan 31 '15 at 04:52
@amitsingh `java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.chen.weather/com.example.chen.weather.WeatherReport}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)` ....... `Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference at )` ... — Zip, Jan 31 '15 at 04:55

score 15 · Answer 1 · answered Jan 31 '15 at 05:00

15

NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText

Means city TextView object is null due to :

1. setContentView is not called before using findViewById:

2. Not using layout in which TextView is defined with city_result id. make sure you are passing right layout in setContentView

answered Jan 31 '15 at 05:00

ρяσѕρєя K

132,198
53
198
213

I'm really new to android. I'm using `super.onCreate(savedInstanceState); setContentView(R.layout.activity_weather_report);` Is this the right one? That should be the filename of the xml file related to this java file. – Zip Jan 31 '15 at 05:04
@Zip: In which layout you have `TextView` with city_result id. ? – ρяσѕρєя K Jan 31 '15 at 05:05
activity_weather_report.xml – Zip Jan 31 '15 at 05:09
@Zip: post `activity_weather_report.xml` layout xml code – ρяσѕρєя K Jan 31 '15 at 05:11
I just restart my android studio and it works! I don't know why but there's no more crash. Thanks anyway! – Zip Jan 31 '15 at 05:14
@ρяσѕρєяK.would you please answer my question? http://stackoverflow.com/q/40817284/4568864 – Mina Dahesh Dec 05 '16 at 14:37

score 3 · Answer 2 · answered Aug 28 '15 at 20:46

3

check that your activity is correct!!

setContentView(R.layout.activity_weather_report);

answered Aug 28 '15 at 20:46

David Hackro

3,652
6
41
61

score 1 · Answer 3 · answered Jan 31 '15 at 05:09

1

Which layout did you put the TextView? I doubt that in this case, you put the TextView in PlaceHolder fragment layout (not the activity_weather_report.xml layout). If so, putting the TextView in activity_weather_report.xml will solve your problem.

answered Jan 31 '15 at 05:09

thuongnh.uit

161
6

I just checked and it seems that something wrong with android studio, I restart it and it works. Thanks anyway! :) – Zip Jan 31 '15 at 05:15

score 1 · Answer 4 · answered Oct 24 '15 at 08:27

1

Problem is just the id

Make sure that you are using correct id for TextView in Layout xml file . I had same issue and it resolved by solving spelling mistake .

answered Oct 24 '15 at 08:27

Faisal Zaheer

33
3

score 0 · Answer 5 · answered Aug 01 '17 at 07:39

0

it is showing this exception because your textview is not getting data at time of onCeate method. declare your textview in onCreate method, put yourtextview.setText(xyz) wherever you are getting that "xyz" value. Hope this will work.

answered Aug 01 '17 at 07:39

user8398214

1

Null object reference on setText in Android app

5 Answers5

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