Add a button to the bottom of Preferences Screen

Question

Despite the content of the comment of @stealthcopter (check answer made by @Andrew) in this question How to add a button to PreferenceScreen, I am not able to visualise a button in the bottom part of my activity.

The application .apk will crash with the following error: Unfortunately your_app has stopped working!

Here is the stack trace from the crash:

05-25 21:26:39.431: I/dalvikvm(1405): threadid=3: reacting to signal 3
05-25 21:26:39.462: I/dalvikvm(1405): Wrote stack traces to '/data/anr/traces.txt'
05-25 21:26:44.851: I/Process(1405): Sending signal. PID: 1405 SIG: 9
05-25 21:40:51.442: I/dalvikvm(1936): threadid=3: reacting to signal 3
05-25 21:40:51.601: I/dalvikvm(1936): Wrote stack traces to '/data/anr/traces.txt'
05-25 21:40:51.951: I/dalvikvm(1936): threadid=3: reacting to signal 3
05-25 21:40:52.001: I/dalvikvm(1936): Wrote stack traces to '/data/anr/traces.txt'
05-25 21:40:52.472: I/dalvikvm(1936): threadid=3: reacting to signal 3
05-25 21:40:52.561: I/dalvikvm(1936): Wrote stack traces to '/data/anr/traces.txt'
05-25 21:40:52.631: D/dalvikvm(1936): GC_CONCURRENT freed 172K, 4% free 9313K/9607K, paused 7ms+7ms
05-25 21:40:52.691: D/gralloc_goldfish(1936): Emulator without GPU emulation detected.
05-25 21:40:54.372: D/AndroidRuntime(1936): Shutting down VM
05-25 21:40:54.372: W/dalvikvm(1936): threadid=1: thread exiting with uncaught exception (group=0x409c01f8)
05-25 21:40:54.422: E/AndroidRuntime(1936): FATAL EXCEPTION: main
05-25 21:40:54.422: E/AndroidRuntime(1936): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.DVA_HLUI/com.DVA_HLUI.DVA_HLUIPrefsActivity}: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'
05-25 21:40:54.422: E/AndroidRuntime(1936):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1956)
05-25 21:40:54.422: E/AndroidRuntime(1936):     at android.app.ActivityThread.startActivityNow(ActivityThread.java:1797)
05-25 21:40:54.422: E/AndroidRuntime(1936):     at android.app.LocalActivityManager.moveToState(LocalActivityManager.java:135)
05-25 21:40:54.422: E/AndroidRuntime(1936):     at android.app.LocalActivityManager.startActivity(LocalActivityManager.java:347)
05-25 21:40:54.422: E/AndroidRuntime(1936):     at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:682)
05-25 21:40:54.422: E/AndroidRuntime(1936):     at android.widget.TabHost.setCurrentTab(TabHost.java:346)
05-25 21:40:54.422: E/AndroidRuntime(1936):     at android.widget.TabHost$2.onTabSelectionChanged(TabHost.java:150)
05-25 21:40:54.422: E/AndroidRuntime(1936):     at android.widget.TabWidget$TabClickListener.onClick(TabWidget.java:540)
05-25 21:40:54.422: E/AndroidRuntime(1936):     at android.view.View.performClick(View.java:3511)
05-25 21:40:54.422: E/AndroidRuntime(1936):     at android.view.View$PerformClick.run(View.java:14105)
05-25 21:40:54.422: E/AndroidRuntime(1936):     at android.os.Handler.handleCallback(Handler.java:605)
05-25 21:40:54.422: E/AndroidRuntime(1936):     at android.os.Handler.dispatchMessage(Handler.java:92)
05-25 21:40:54.422: E/AndroidRuntime(1936):     at android.os.Looper.loop(Looper.java:137)
05-25 21:40:54.422: E/AndroidRuntime(1936):     at android.app.ActivityThread.main(ActivityThread.java:4424)
05-25 21:40:54.422: E/AndroidRuntime(1936):     at java.lang.reflect.Method.invokeNative(Native Method)
05-25 21:40:54.422: E/AndroidRuntime(1936):     at java.lang.reflect.Method.invoke(Method.java:511)
05-25 21:40:54.422: E/AndroidRuntime(1936):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
05-25 21:40:54.422: E/AndroidRuntime(1936):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
05-25 21:40:54.422: E/AndroidRuntime(1936):     at dalvik.system.NativeStart.main(Native Method)
05-25 21:40:54.422: E/AndroidRuntime(1936): Caused by: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'
05-25 21:40:54.422: E/AndroidRuntime(1936):     at android.app.ListActivity.onContentChanged(ListActivity.java:243)
05-25 21:40:54.422: E/AndroidRuntime(1936):     at android.preference.PreferenceActivity.onContentChanged(PreferenceActivity.java:944)
05-25 21:40:54.422: E/AndroidRuntime(1936):     at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:254)
05-25 21:40:54.422: E/AndroidRuntime(1936):     at android.app.Activity.setContentView(Activity.java:1835)
05-25 21:40:54.422: E/AndroidRuntime(1936):     at com.DVA_HLUI.DVA_HLUIPrefsActivity.onCreate(DVA_HLUIPrefsActivity.java:15)
05-25 21:40:54.422: E/AndroidRuntime(1936):     at android.app.Activity.performCreate(Activity.java:4465)
05-25 21:40:54.422: E/AndroidRuntime(1936):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
05-25 21:40:54.422: E/AndroidRuntime(1936):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920)
05-25 21:40:54.422: E/AndroidRuntime(1936):     ... 18 more

Here is the activity java class that crashes:

public class DVA_HLUIPrefsActivity extends PreferenceActivity 
{
   @Override
   public void onCreate(Bundle savedInstanceState) 
   { 
        super.onCreate(savedInstanceState);
        addPreferencesFromResource(R.xml.prefs);
        setContentView(R.layout.preferences);
   }
}

Here is its layout file:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical">

    <ListView
        android:id="@+id/list"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" android:layout_weight="1">
    </ListView>

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content">

        <Button
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="Quit!" android:layout_weight="0.5"android:layout_gravity="center_vertical"
         />

        <Button
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="Help" android:layout_weight="0.5" android:layout_gravity="center_vertical"
         />

    </LinearLayout>

</LinearLayout>

and finally this is the preferences xml resource:

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" >

    <Preference android:key="about" android:title="@string/titleAbout" android:summary="@string/summaryAbout" />


</PreferenceScreen>

Can you please explain me what is the conflict that causes the application to crash?

And in the stacktrace is the answer you are looking for. Someone else explained it too it seems. — Mattias Isegran Bergander, May 25 '12 at 20:03
@Pulsar I'm a newbie to android and maybe I haven't understood well, but preferences aren't usually defined as I did in the preferences xml resource?What am I getting wrong?If I replace that with the code in the answer below there will be an eclipse error: `error: Error parsing XML: unbound prefix` — Matteo, May 25 '12 at 20:12
Only thing you need to change in your code is that listed in that answer, the `android:id="@android:id/list"` attribute for your list view. — Mattias Isegran Bergander, May 25 '12 at 20:20
@Pulsar +1..I got it, so the problem was not the preference xml resource but the preferences layout, having this id `"@+id/list"` instead of this `"@android:id/list"`. Anyway, what's the difference between the 2? — Matteo, May 25 '12 at 20:25
`@+id/list` adds a new id to *your* resources named `list`, while uses an already defined id, in this case in android itself: `@android:id/list` — Mattias Isegran Bergander, May 25 '12 at 20:28

score 4 · Accepted Answer · edited May 23 '17 at 12:27

4

You have to include a ListView with the id @android:id/list like it says in the question you linked to (See Answer).

From your android layout file (R.Layout.Preferences) remove your <ListView> and put this in it's place.

<ListView android:id="@android:id/list" 
  android:layout_width="fill_parent"
  android:layout_height="fill_parent" />

That should solve the problem you were having.

From the LogCat you posted: Caused by: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'

Edit: Just some clarification of the id attribute on the ListView. From Android XML Layouts.

The syntax for an ID, inside an XML tag is:

android:id="@+id/my_button"

The at-symbol (@) at the beginning of the string indicates that the XML parser should parse and expand the rest of the ID string and identify it as an ID resource. The plus-symbol (+) means that this is a new resource name that must be created and added to our resources (in the R.java file). There are a number of other ID resources that are offered by the Android framework. When referencing an Android resource ID, you do not need the plus-symbol, but must add the android package namespace, like so:

android:id="@android:id/empty"

With the android package namespace in place, we're now referencing an ID from the android.R resources class, rather than the local resources class.

edited May 23 '17 at 12:27

Community

1
1

answered May 25 '12 at 19:56

javajavajavajavajava

1,223
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20

in the [Answer](http://stackoverflow.com/questions/2697233/how-to-add-a-button-to-preferencescreen/3026922#3026922) it is written `preferences defined the usual way in res/xml/preferences.xml` which is exactly what I did with the tag – Matteo May 25 '12 at 20:07
Hey @Matteo Your R.xml.prefs looks fine, you don't need to change that. You just need to change the android:id of your ListView in the R.layout.preferences file. I see that you've changed the id of the ListView to "@+id/list"... It needs to be "@android:id/list". Let me know if this solves it for you – javajavajavajavajava May 25 '12 at 20:24
yeah that was the issue!!thks a lot for help. btw what is the difference between the 2 ways of writing the id? – Matteo May 25 '12 at 20:27
@Matteo Great! I'm glad that fixed it for you. I added some more detail to the Answer to explain why these are different. Basically, we don't want to create a NEW ListView, we just want to use the standard Android ListView that PreferenceScreen is expecting. – javajavajavajavajava May 25 '12 at 20:33
That was of great help, sorry I can't +2... ;D thks again, bye ;D – Matteo May 25 '12 at 20:35

Add a button to the bottom of Preferences Screen

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