Android packagemanager list causing app to crash

Question

I am fairly new to Android programming. I downloaded Android Studio today and started a new project. I added an empty activity to the form with a textview with the following code.

XML:

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text=""
    android:id="@+id/textView1"
    android:layout_alignParentBottom="true"
    android:layout_alignParentRight="true"
    android:layout_alignParentEnd="true"
    android:layout_alignParentTop="true"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true" />

MAIN CODE:

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    int flags = PackageManager.GET_META_DATA |
            PackageManager.GET_SHARED_LIBRARY_FILES |
            PackageManager.GET_UNINSTALLED_PACKAGES;

    PackageManager pm = getPackageManager();
    List<ApplicationInfo> applications = pm.getInstalledApplications(flags);
    List<String> applicationsInstalled = new ArrayList<String>();
    for (ApplicationInfo appInfo : applications) {
        if ((appInfo.flags & ApplicationInfo.FLAG_SYSTEM) == 1) {
            // System application
        } else {
            // Installed by user
            applicationsInstalled.add(appInfo.name);
        }
    }
    TextView tv1 = (TextView)findViewById(R.id.textView1);
    for (String app : applicationsInstalled)
    {
        tv1.append(app);
    }
    setContentView(R.layout.activity_main);
}
}

For some reason, the app crashes as soon as it launches. If I remove the code I wrote and only keep till

setContentView(R.layout.activity_main);

it works fine but is empty.

EDIT: Stacktrace https://pastebin.com/dHHygFkQ

@fbwnd I just added the stacktrace option to the command line (googled it, idk what it is). where do i see its output? — Haardik, Dec 04 '16 at 15:52
You can see it from the AndroidStudio. If you prefer the command line use: adb logcat -s AndroidRuntime and paste the output (when it crashes) here — fbwnd, Dec 04 '16 at 15:54
first of all you call setContentView() 2 times. remove the last one — Kostas Drak, Dec 04 '16 at 15:57
@KostasDrak sorry im new and this maybe a stupid doubt but isnt the second one supposed to 'refresh' the view with the updated text? — Haardik, Dec 04 '16 at 15:58
of course not....you are calling the layout twice. if you want to update the layout you will have to use runOnUiThread() which accepts a Runnable and in there you will update the UI — Kostas Drak, Dec 04 '16 at 15:59
updated stacktrace with the oen from android monitor in the IDE @fbwnd — Haardik, Dec 04 '16 at 16:02
I just noticed that part in the stack. That's the thing - I don't. This code is all I have for now and I am just messing around with lists. — Haardik, Dec 04 '16 at 16:06
For now, getting the list of third party user installed apps on the phone. — Haardik, Dec 04 '16 at 16:10

score 0 · Accepted Answer · edited May 23 '17 at 12:01

0

As said in the comments, remove the second setContentView.

You are passing null to tv1.append. As appInfo.name returns null. See PackageManager's applicationInfo.name is always null

Use: (String)pm.getApplicationLabel(appInfo).

For example:

applicationsInstalled.add((String)pm.getApplicationLabel(appInfo))

edited May 23 '17 at 12:01

Community

1
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answered Dec 04 '16 at 16:07

fbwnd

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this will only get the current application label – Kostas Drak Dec 04 '16 at 16:12
@KostasDrak Not according to: https://developer.android.com/reference/android/content/pm/PackageManager.html#getApplicationLabel(android.content.pm.ApplicationInfo) – fbwnd Dec 04 '16 at 16:12
@Haardik I would recommend to verify that pm.getApplicationLabel(appInfo) isn't null before adding to the list. – fbwnd Dec 04 '16 at 16:13
@fbwnd I'll do that, thanks. But if i may ask, why would it ever be null? – Haardik Dec 04 '16 at 16:16
It shouldn't be, though, as mentioned in the documentation (https://developer.android.com/reference/android/content/pm/PackageManager.html#getApplicationLabel(android.content.pm.ApplicationInfo)). It can be – fbwnd Dec 04 '16 at 16:17

Android packagemanager list causing app to crash

1 Answers1