How to call custom preference

Question

Hi I'm trying to call a custom preference. Why does the application crash?

When I set up the custom preference in preference.xml, the application breaks at "com.appdev.customprefs.SeekBarPreference". I want it to use SeekBarPreference.java and I thought I needed to include the package.SeekBarPreference to get it to work.

xml/preferences.xml

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" >
    <com.appdev.customprefs.SeekBarPreference
        android:title="Custom Preference"
        android:key="customPref"
        android:defaultValue="32""/>
</PreferenceScreen>

stacktrace

11-17 20:02:17.920: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:18.100: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:18.100: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:19.080: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:19.080: I/Choreographer(1482): Skipped 41 frames! The application may be doing too much work on its main thread. 11-17 20:02:19.080: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:19.110: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:19.130: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:19.271: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:19.271: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:19.290: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:19.340: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:19.360: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:19.360: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:19.360: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:19.360: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:19.360: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:19.380: D/grallo c_goldfish(1482): Emulator without GPU emulation detected. 11-17 20:02:19.530: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:19.580: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:21.980: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:21.980: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:22.011: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:22.020: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:22.080: D/dalvikvm(1482): GC_FOR_ALLOC freed 115K, 9% free 2602K/2836K, paused 39ms, total 42ms 11-17 20:02:22.090: I/dalvikvm-heap(1482): Grow heap (frag case) to 3.259MB for 635812-byte allocation 11-17 20:02:22.200: D/dalvikvm(1482): GC_FOR_ALLOC freed 3K, 7% free 3220K/3460K, paused 120ms, total 120ms 11-17 20:02:22.470: D/dalvikvm(1482): GC_CONCURRENT freed <1K, 7% free 3239K/3460K, paused 81ms+130ms, total 266ms 11-17 20:02:22.521: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:22.530: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:22.580: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:22.710: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:22.760: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:22.760: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:22.790: I/Choreographer(1482): Skipped 67 frames! The application may be doing too much work on its main thread. 11-17 20:02:22.790: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:22.790: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:22.810: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:22.860: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:22.870: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:22.910: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:22.960: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:22.960: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:23.010: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:23.020: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:23.080: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:23.160: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:23.852: W/Trace( 1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:23.852: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:23.890: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:23.890: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:23.920: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:23.920: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:23.970: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:23.970: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:23.970: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:23.970: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:24.010: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:24.010: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:24.030: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:24.030: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:24.050: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:24.050: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:24.142: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:24.142: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:24.180: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:24.180: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:24.554: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:24.572: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:24.650: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:24.650: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:24.650: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11- 17 20:02:24.650: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:24.670: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:24.670: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:24.810: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:24.810: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:24.820: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:24.820: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:24.820: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:24.880: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:24.940: W/Trace(1482): Unexpected value from nativeGetEnabledTags: 0 11-17 20:02:25.410: D/AndroidRuntime(1482): Shutting down VM 11-17 20:02:25.410: W/dalvikvm(1482): threadid=1: thread exiting with uncaught exception (group=0x40a70930) 11-17 20:02:25.540: E/An droidRuntime(1482): FATAL EXCEPTION: main 11-17 20:02:25.540: E/AndroidRuntime(1482): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.appdev.customprefs/com.appdev.customprefs.preferences}: android.view.InflateException: Binary XML file line #4: Error inflating class com.appdev.customprefs.SeekBarPreference 11-17 20:02:25.540: E/AndroidRuntime(1482): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180) 11-17 20:02:25.540: E/AndroidRuntime(1482): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230) 11-17 20:02:25.540: E/AndroidRuntime(1482): at android.app.ActivityThread.access$600(ActivityThread.java:141) 11-17 20:02:25.540: E/AndroidRuntime(1482): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234) 11-17 20:02:25.540: E/AndroidRuntime(1482): at android.os.Handler.dispatchMessage(Handler.java:99) 11-17 20:02:25.540: E/AndroidRuntime(1482): at android.os.Looper.loop(Looper.java:137) 11-17 20:02:2 5.540: E/AndroidRuntime(1482): at android.app.ActivityThread.main(ActivityThread.java:5039) 11-17 20:02:25.540: E/AndroidRuntime(1482): at java.lang.reflect.Method.invokeNative(Native Method) 11-17 20:02:25.540: E/AndroidRuntime(1482): at java.lang.reflect.Method.invoke(Method.java:511) 11-17 20:02:25.540: E/AndroidRuntime(1482): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 11-17 20:02:25.540: E/AndroidRuntime(1482): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 11-17 20:02:25.540: E/AndroidRuntime(1482): at dalvik.system.NativeStart.main(Native Method) 11-17 20:02:25.540: E/AndroidRuntime(1482): Caused by: android.view.InflateException: Binary XML file line #4: Error inflating class com.appdev.customprefs.SeekBarPreference 11-17 20:02:25.540: E/AndroidRuntime(1482): at android.preference.GenericInflater.createItem(GenericInflater.java:386) 11-17 20:02:25.540: E/AndroidRuntime(1482): at android.preference.GenericInflater.createIte mFromTag(GenericInflater.java:430) 11-17 20:02:25.540: E/AndroidRuntime(1482): at android.preference.GenericInflater.rInflate(GenericInflater.java:481) 11-17 20:02:25.540: E/AndroidRuntime(1482): at android.preference.GenericInflater.rInflate(GenericInflater.java:493) 11-17 20:02:25.540: E/AndroidRuntime(1482): at android.preference.GenericInflater.inflate(GenericInflater.java:326) 11-17 20:02:25.540: E/AndroidRuntime(1482): at android.preference.GenericInflater.inflate(GenericInflater.java:263) 11-17 20:02:25.540: E/AndroidRuntime(1482): at android.preference.PreferenceManager.inflateFromResource(PreferenceManager.java:269) 11-17 20:02:25.540: E/AndroidRuntime(1482): at android.preference.PreferenceActivity.addPreferencesFromResource(PreferenceActivity.java:1424) 11-17 20:02:25.540: E/AndroidRuntime(1482): at com.appdev.customprefs.preferences.onCreate(preferences.java:12) 11-17 20:02:25.540: E/AndroidRuntime(1482): at android.app.Activity.performCreate(Activity.java:5104) 11-17 20:02 :25.540: E/AndroidRuntime(1482): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) 11-17 20:02:25.540: E/AndroidRuntime(1482): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144) 11-17 20:02:25.540: E/AndroidRuntime(1482): ... 11 more 11-17 20:02:25.540: E/AndroidRuntime(1482): Caused by: java.lang.NoSuchMethodException: [class android.content.Context, interface android.util.AttributeSet] 11-17 20:02:25.540: E/AndroidRuntime(1482): at java.lang.Class.getConstructorOrMethod(Class.java:460) 11-17 20:02:25.540: E/AndroidRuntime(1482): at java.lang.Class.getConstructor(Class.java:431) 11-17 20:02:25.540: E/AndroidRuntime(1482): at android.preference.GenericInflater.createItem(GenericInflater.java:377) 11-17 20:02:25.540: E/AndroidRuntime(1482): ... 22 more 11-17 20:02:28.760: I/Process(1482): Sending signal. PID: 1482 SIG: 9

SeekBarPreference.java

public class SeekBarPreference extends Preference implements OnSeekBarChangeListener
{

public SeekBarPreference(Context context)
{   
    super(context);
    Log.i("SBP", "In SBP!");
}

@Override
public void onProgressChanged(SeekBar arg0, int arg1, boolean arg2) {
    // TODO Auto-generated method stub

}

@Override
public void onStartTrackingTouch(SeekBar arg0) {
    // TODO Auto-generated method stub

}

@Override
public void onStopTrackingTouch(SeekBar arg0) {
    // TODO Auto-generated method stub

}

@Override
protected View onCreateView(ViewGroup parent) {
    Log.i("SBP", "In SBP2!");
    return super.onCreateView(parent);
}

}

Answer 1

You implemented only one constructor. To be able use Preference , you should implement 2 other constructors from Preference :

Just Implement These Two Constructor also:

Preference(Context context, AttributeSet attrs)

Preference(Context context, AttributeSet attrs, int defStyle)

Here your log: Caused by: java.lang.NoSuchMethodException: [class android.content.Context, interface android.util.AttributeSet]