NullPointerException when inflating custom InfoWindowAdapter

Question

I am trying to extract a custom InfoWindowAdapter into a separate class file. I started with an inner class which works perfect:

public class FoobarMapActivity extends SherlockFragmentActivity {

    protected GoogleMap mMap;
    private final GoogleMap.InfoWindowAdapter mInfoWindowAdapter;

    public FoobarMapActivity() {
        mInfoWindowAdapter = new GoogleMap.InfoWindowAdapter() {

            @Override
            public View getInfoWindow(Marker marker) {
                View window = getLayoutInflater().inflate(R.layout.custom_info_window, null);
                render(marker, window);
                return window;
            }

            @Override
            public View getInfoContents(Marker marker) {
                return null;
            }

            private void render(Marker marker, View view) {
                ((ImageView) view.findViewById(R.id.badge)).setImageResource(0);
                TextView titleTextView = ((TextView) view.findViewById(R.id.title));
                TextView snippetTextView = ((TextView) view.findViewById(R.id.snippet));
                titleTextView.setText(StringHelper.setTextOrEmpty(marker.getTitle()));
                snippetTextView.setText(StringHelper.setTextOrEmpty(marker.getSnippet()));
            }

        };
    }

But as soon as I put the same code into a separate class I run into a NullPointerException when I inflate the layout.

Caused by: java.lang.NullPointerException
  at android.view.LayoutInflater.from(LayoutInflater.java:210)
  at com.example.foobar.activities.CustomInfoWindowAdapter.<init>(CustomInfoWindowAdapter.java:20)
  at com.example.foobar.activities.FoobarMapActivity.<init>(FoobarMapActivity.java:107)
  at java.lang.Class.newInstanceImpl(Native Method)
  at java.lang.Class.newInstance(Class.java:1319)
  at android.app.Instrumentation.newActivity(Instrumentation.java:1023)
  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1887)

Here is the custom class for the InfoWindowAdapter:

package com.example.foobar.activities;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;

import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.model.Marker;

import com.example.foobar.R;
import com.example.foobar.utils.StringHelper;

public class CustomInfoWindowAdapter implements GoogleMap.InfoWindowAdapter {

    protected View mWindow;

    public CustomInfoWindowAdapter(Context context) {
        LayoutInflater inflater = LayoutInflater.from(context);
        mWindow = inflater.inflate(R.layout.custom_info_window, null);
    }

    @Override
    public View getInfoWindow(Marker marker) {
        render(marker, mWindow);
        return mWindow;


    @Override
    public View getInfoContents(Marker marker) {
        return null;
    }

    private void render(Marker marker, View view) {
        ((ImageView) view.findViewById(R.id.badge)).setImageResource(0);
        TextView titleTextView = ((TextView) view.findViewById(R.id.title));
        TextView snippetTextView = ((TextView) view.findViewById(R.id.snippet));
        titleTextView.setText(StringHelper.setTextOrEmpty(marker.getTitle()));
        snippetTextView.setText(StringHelper.setTextOrEmpty(marker.getSnippet()));
    }

}

Here I instatiate the custom adapter:

public class FoobarMapActivity extends SherlockFragmentActivity {

    private final GoogleMap.InfoWindowAdapter mInfoWindowAdapter;

    public FoobarMapActivity() {
        mInfoWindowAdapter = new CustomInfoWindowAdapter(getBaseContext()); // line 107
    }

The XML should not be the problem since it works with the inner class. — JJD, Jun 22 '13 at 12:03
@MDMalik Please revert your edit: I included the imports on purpose since this could be the cause of the problem, e.g. the reference to `R.`. — JJD, Jun 22 '13 at 12:16
@JJD What is FoobarMapActivity.java:107 and CustomInfoWindowAdapter.java:20 can u tell me? — TheFlash, Jun 22 '13 at 12:55
@Pratik I appended the line numbers in the code as comments. — JJD, Jun 22 '13 at 13:00
public class FoobarMapActivity // public TreesMapActivity() WAT? — BoD, Jun 22 '13 at 14:45

score 2 · Answer 1 · answered Jun 22 '13 at 14:18

2

Please move this line:

mInfoWindowAdapter = new CustomInfoWindowAdapter(getBaseContext());

into onCreate and replace getBaseContext() with this.

You are doing something against the platform. onCreate is your constructor and you should not use Java constructor when working with Activities.

answered Jun 22 '13 at 14:18

MaciejGórski

22,187
7
70
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2

Indeed, please remove your constructor, and use onCreate instead. Dianne Hackborn (from the Android team) said: "Simple answer: if you are implementing a component like Activity, Service, and ContentProvider, don't implement a constructor. (That is just use the default empty constructor). Whatever you think you want to do in the constructor... you very like don't, and should do in onCreate() instead." - https://groups.google.com/forum/#!topic/android-developers/70VaBROqcxg – BoD Jun 22 '13 at 15:03
What would be your suggestion to ensure the instance is constructed once only then? – JJD Jun 25 '13 at 11:59
1

@JJD `onCreate` is called only once just after constructor is invoked. – MaciejGórski Jun 25 '13 at 12:59

Dimmerg · Answer 2 · 2013-06-22T12:21:44.853

0

I think you have NullReference in render function Try to add null checking:

private void render(Marker marker, View view) {
        if (view == null || marker == null)
          return;
        ((ImageView) view.findViewById(R.id.badge)).setImageResource(0);
        TextView titleTextView = ((TextView) view.findViewById(R.id.title));
        TextView snippetTextView = ((TextView) view.findViewById(R.id.snippet));
        if (titleTextView != null)
          titleTextView.setText(StringHelper.setTextOrEmpty(marker.getTitle()));
        if (snippetTextView!= null)
          snippetTextView.setText(StringHelper.setTextOrEmpty(marker.getSnippet()));
    }

EDITED:

Try to get LayoutInflater another way:

mInflater = (LayoutInflater) context.getSystemService( Context.LAYOUT_INFLATER_SERVICE);

and also check that context is not null.

EDITED2:

Try

mInfoWindowAdapter = new CustomInfoWindowAdapter(this);

edited Jun 22 '13 at 12:21

answered Jun 22 '13 at 11:58

Dimmerg

2,113
1
13
14

Please read the stacktrace. The error occurs when the layout is inflated in the constructor of `CustomInfoWindowAdapter`. – JJD Jun 22 '13 at 12:03
The same exception is thrown when I use `context.getSystemService()` to retrieve the inflater. – JJD Jun 22 '13 at 12:14
So, we have another question - why context passed in constructor is null :) Can you provide code, where you create and set this adapter for map? – Dimmerg Jun 22 '13 at 12:16
Pass `this` to the adapter causes an `IllegalStateException: System services not available to Activities before onCreate()`. I tried both variation to retrieve the inflater. I cannot move the instantiation info `onCreate` since I declared it to be final. – JJD Jun 22 '13 at 12:34
Why did you mark adapter as final? Is it possible to make it standart class variable and move adapter constructor into onCreate? – Dimmerg Jun 22 '13 at 13:17
I declare the adapter as `final` to avoid recreating it every once in a while. – JJD Jun 22 '13 at 13:20
I think you have more problems with this solution, because your adapter anyway will create info view again on each call. – Dimmerg Jun 22 '13 at 13:26
I can avoid this by moving `mInflater.inflate(R.layout.custom_info_window, null);` into the constructor. – JJD Jun 22 '13 at 13:48
Do you mean to inflate view into activity and pass it into adapter, than adapter will return this view? – Dimmerg Jun 22 '13 at 13:51
So, you are really avoid recreating, but your problem still not solved? – Dimmerg Jun 22 '13 at 14:12

score 0 · Answer 3 · edited Jun 22 '13 at 12:56

0

Try to use getApplicationContext() or your Activity's context instead of getBaseContext(). Context context = this; make context globle to your activity.

edited Jun 22 '13 at 12:56

JJD

50,076
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answered Jun 22 '13 at 12:47

Vijju

3,458
1
22
20

Passing `getApplicationContext()` also causes a `NullPointerException. This is also against [how you should use context](http://www.doubleencore.com/2013/06/context/?utm_source=Android+Weekly&utm_campaign=78ad4cb95e-Android_Weekly_64&utm_medium=email&utm_term=0_4eb677ad19-78ad4cb95e-330180005). – JJD Jun 22 '13 at 12:54

NullPointerException when inflating custom InfoWindowAdapter

3 Answers3