Franco Franco - 2 months ago 14
Android Question

PreferenceScreen class not found

I have this in preferences.xml

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

<CheckBoxPreference
android:key="displayNotification"
android:title="Display notification"
/>

<ListPreference
android:entries="@array/languages"
android:key="language"
/>
</PreferenceScreen>


PreferencesActivity.java, the class that uses this xml

public class PreferencesActivity extends PreferenceActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);

setContentView(R.xml.preferences);
}
}


And I have it declared in the manifest like this

<activity android:name="com.tellthetime.PreferencesActivity" />


When I start the activity I get a class not found exception, which I don't understand.

05-17 00:35:13.633: ERROR/AndroidRuntime(212): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.tellthetime/com.tellthetime.PreferencesActivity}: android.view.InflateException: Binary XML file line #2: Error inflating class PreferenceScreen
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at android.app.ActivityThread.access$2200(ActivityThread.java:119)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at android.os.Handler.dispatchMessage(Handler.java:99)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at android.os.Looper.loop(Looper.java:123)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at android.app.ActivityThread.main(ActivityThread.java:4363)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at java.lang.reflect.Method.invokeNative(Native Method)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at java.lang.reflect.Method.invoke(Method.java:521)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at dalvik.system.NativeStart.main(Native Method)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): Caused by: android.view.InflateException: Binary XML file line #2: Error inflating class PreferenceScreen
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:576)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at android.view.LayoutInflater.inflate(LayoutInflater.java:385)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at android.view.LayoutInflater.inflate(LayoutInflater.java:320)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at android.view.LayoutInflater.inflate(LayoutInflater.java:276)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:198)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at android.app.Activity.setContentView(Activity.java:1622)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at com.tellthetime.PreferencesActivity.onCreate(PreferencesActivity.java:13)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): ... 11 more
05-17 00:35:13.633: ERROR/AndroidRuntime(212): Caused by: java.lang.ClassNotFoundException: android.view.PreferenceScreen in loader dalvik.system.PathClassLoader@44c067e8
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:243)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at java.lang.ClassLoader.loadClass(ClassLoader.java:573)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at java.lang.ClassLoader.loadClass(ClassLoader.java:532)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at android.view.LayoutInflater.createView(LayoutInflater.java:466)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at android.view.LayoutInflater.onCreateView(LayoutInflater.java:544)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at com.android.internal.policy.impl.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:66)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:563)
05-17 00:35:13.633: ERROR/AndroidRuntime(212): ... 19 more


This was already asked here but no one answered. As pointed out in that thread by Heiko Rupp, android is looking for the class in the package
android.view
, but the class is in
android.preferences
, this really lost me.

Answer

You're getting confused, you're trying to set the preference definition as the layout definition. First set a layout for the Activity, then bind your preferences XML:

  ...
  setContentView(R.layout.layout);
  addPreferencesFromResource(R.xml.preferences);
  ...
Comments