show text after pressing button in android - android

I'm new to android, now i want to press a button then display text on the screen. here's my code:
xml
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="sendMessages"
android:text="Button" />
<TextView
android:id="#+id/buttonText"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
android:ems="10"
android:inputType="textMultiLine"
android:text="hello" />
main activity
public class MainActivity extends ActionBarActivity {
protected void onCreate(Bundle savedInstanceState){
.......
}
public void sendMessages(View view) {
TextView welcome = (TextView) findViewById(R.id.buttonText);
welcome.setText("button clicked");
}
}
but when i run this on a simulator, after pressing the button, the application will report
fortunately, First Android App has stopped
does anyone know what's wrong with my program?
04-18 00:56:20.147: D/AndroidRuntime(1280): Shutting down VM
04-18 00:56:20.147: W/dalvikvm(1280): threadid=1: thread exiting with uncaught exception (group=0x40a13300)
04-18 00:56:20.177: E/AndroidRuntime(1280): FATAL EXCEPTION: main
04-18 00:56:20.177: E/AndroidRuntime(1280): java.lang.IllegalStateException: Could not execute method of the activity
04-18 00:56:20.177: E/AndroidRuntime(1280): at android.view.View$1.onClick(View.java:3591)
04-18 00:56:20.177: E/AndroidRuntime(1280): at android.view.View.performClick(View.java:4084)
04-18 00:56:20.177: E/AndroidRuntime(1280): at android.view.View$PerformClick.run(View.java:16966)
04-18 00:56:20.177: E/AndroidRuntime(1280): at android.os.Handler.handleCallback(Handler.java:615)
04-18 00:56:20.177: E/AndroidRuntime(1280): at android.os.Handler.dispatchMessage(Handler.java:92)
04-18 00:56:20.177: E/AndroidRuntime(1280): at android.os.Looper.loop(Looper.java:137)
04-18 00:56:20.177: E/AndroidRuntime(1280): at android.app.ActivityThread.main(ActivityThread.java:4745)
04-18 00:56:20.177: E/AndroidRuntime(1280): at java.lang.reflect.Method.invokeNative(Native Method)
04-18 00:56:20.177: E/AndroidRuntime(1280): at java.lang.reflect.Method.invoke(Method.java:511)
04-18 00:56:20.177: E/AndroidRuntime(1280): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
04-18 00:56:20.177: E/AndroidRuntime(1280): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
04-18 00:56:20.177: E/AndroidRuntime(1280): at dalvik.system.NativeStart.main(Native Method)
04-18 00:56:20.177: E/AndroidRuntime(1280): Caused by: java.lang.reflect.InvocationTargetException
04-18 00:56:20.177: E/AndroidRuntime(1280): at java.lang.reflect.Method.invokeNative(Native Method)
04-18 00:56:20.177: E/AndroidRuntime(1280): at java.lang.reflect.Method.invoke(Method.java:511)
04-18 00:56:20.177: E/AndroidRuntime(1280): at android.view.View$1.onClick(View.java:3586)
04-18 00:56:20.177: E/AndroidRuntime(1280): ... 11 more
04-18 00:56:20.177: E/AndroidRuntime(1280): Caused by: java.lang.ClassCastException: android.widget.FrameLayout cannot be cast to android.widget.TextView
04-18 00:56:20.177: E/AndroidRuntime(1280): at com.example.firstandroidapp.MainActivity.sendMessages(MainActivity.java:110)
04-18 00:56:20.177: E/AndroidRuntime(1280): ... 14 more


Do button and TextView exist in the activity layout?
Do you call setContentView(Layout) in onCreate?
Are you working with ADT?
If you are working with ADT you can create a new activity and
a new xml layout, so call setContentView(R.layout.YourLayout)
in onCreate
YourLayout.xml has to contains button and TextView

Related

Cordova hello world app crashing

I am new in Android Development. I am working on cordova platform
I have created a sample hello world app and getting this error when i am trying to open it in genymotion. ALthough the app compile succesfully but when i run it in genymotion it just shows the prompt with text "Unfortunately "APP" has stopped."
The Error log shows.
01-12 08:16:04.867 2073-2073/com.technoserves.crudnew D/dalvikvm﹕ Late-enabling CheckJNI
01-12 08:16:06.107 2073-2073/com.technoserves.crudnew W/dalvikvm﹕ Unable to resolve superclass of Lcom/technoserves/crudnew/CordovaApp; (14)
01-12 08:16:06.119 2073-2073/com.technoserves.crudnew W/dalvikvm﹕ Link of class 'Lcom/technoserves/crudnew/CordovaApp;' failed
01-12 08:16:06.135 2073-2073/com.technoserves.crudnew D/AndroidRuntime﹕ Shutting down VM
01-12 08:16:06.135 2073-2073/com.technoserves.crudnew W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0xa6142908)
01-12 08:16:06.155 2073-2073/com.technoserves.crudnew E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.technoserves.crudnew/com.technoserves.crudnew.CordovaApp}: java.lang.ClassNotFoundException: Didn't find class "com.technoserves.crudnew.CordovaApp" on path: /data/app/com.technoserves.crudnew-1.apk
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2106)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5041)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.ClassNotFoundException: Didn't find class "com.technoserves.crudnew.CordovaApp" on path: /data/app/com.technoserves.crudnew-1.apk
at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:65)
at java.lang.ClassLoader.loadClass(ClassLoader.java:501)
at java.lang.ClassLoader.loadClass(ClassLoader.java:461)
at android.app.Instrumentation.newActivity(Instrumentation.java:1054)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2097)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
            at android.app.ActivityThread.access$600(ActivityThread.java:141)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:137)
            at android.app.ActivityThread.main(ActivityThread.java:5041)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:511)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
            at dalvik.system.NativeStart.main(Native Method)
01-12 08:16:22.399 2073-2073/com.technoserves.crudnew I/Process﹕ Sending signal. PID: 2073 SIG: 9
I have updated my cordova to resolve but still same error however a few days ago it was working fine and i have build some apps.

First download Cordova jar file from following link:
http://www.java2s.com/Code/JarDownload/cordova/cordova-1.8.1.jar.zip
after that extract the folder and put cordova-1.8.1 inside your libs folder of project in eclipse
And right click on your project--> properties and Select Android from left pane and scroll to bottom remove the cordova library if added.
then clean and build your project.

findViewById on an ImageView why does setBackgroundColor give NullPointerException

I have a very basic activity with an ImageView of android:id="#+id/imageViewTest"
and then in the OnCreate method calling:
ImageView imageView = (ImageView)findViewById(R.id.imageViewTest);
// Set the background color to white
imageView.setBackgroundColor(Color.WHITE);
this gives error:
10-15 16:36:27.552 29097-29097/org.explore.self.beginner D/dalvikvm﹕ Late-enabling CheckJNI
10-15 16:36:28.017 29097-29097/org.explore.self.beginner D/AndroidRuntime﹕ Shutting down VM
10-15 16:36:28.017 29097-29097/org.explore.self.beginner W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0x41d9b2a0)
10-15 16:36:28.042 29097-29097/org.explore.self.beginner E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{org.explore.self.beginner/org.selfexplore.android.view.activity.TestActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2110)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2135)
at android.app.ActivityThread.access$700(ActivityThread.java:140)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1237)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4921)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at org.selfexplore.android.view.activity.TestActivity.onCreate(TestActivity.java:37)
at android.app.Activity.performCreate(Activity.java:5188)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2074)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2135)
            at android.app.ActivityThread.access$700(ActivityThread.java:140)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1237)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:137)
            at android.app.ActivityThread.main(ActivityThread.java:4921)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:511)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
            at dalvik.system.NativeStart.main(Native Method)
10-15 16:36:28.062 29097-29097/org.explore.self.beginner I/Process﹕ Sending signal. PID: 29097 SIG: 9
But when I do a
ImageView imageView = new ImageView(this);
it works fine, Why?
PS: I am not able to add the layout code here, so sharing it in this doc: https://docs.google.com/document/d/1fbi3B_hAYUh_C2IwPfInvZ-BG2bgsa4pZoJKj8NBT9o/edit?usp=sharing

Your layout you've set with setContentView() doesn't have a view with id imageViewTest and findViewById() returns null, or you haven't called setContentView() at all.

Store/Save & Retrieve to/from SharedPreference Failure

I've been having so much problem with this Live Wallpaper.
I have read alot online about these, and I thought I understood and got them.
When I tried to apply them to this live wallpaper, everything has been going very rough.
I've spent all day and night :-(
Could you someone please help me out?
My goal is to store the new password from edittextpreference to the
Sharedpreference, and then retrieve this password to compared with the login
password to if they are matched.
For example,
I have 2 edittextpreferences:
1) is for create new password which will be saved to the SharedPreference
2) is for login password.
The users will be granted the access when the login password is matched with the
one in the SharedPreference.
Please help me out,
I would be appreciated for your help.
prefs.java Code:
#SuppressWarnings("deprecation")
#Override
protected void onDestroy() {
getPreferenceManager().getSharedPreferences()
.unregisterOnSharedPreferenceChangeListener(this);
super.onDestroy();
}
public void onSharedPreferenceChanged(SharedPreferences sharedPreferences,
String key) {
// TODO Auto-generated method stub
{
}
}
{
SharedPreferences mlogin_password = this.getSharedPreferences("data_storage", MODE_PRIVATE);
Editor login_password = mlogin_password.edit();
login_password.putString("login", "login_pw2");
login_password.commit();
SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(Context);
String s = sp.getString("login", null);
Sorry for 10000000 of error codes :-(
Logcat:
at android.util.Log.println_native(Native Method)
at android.util.Log.v(Log.java:117)
at rare_war.weapons.prefs.<init>(prefs.java:60)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1130)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2128)
... 11 more
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2137)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
at rare_war.weapons.prefs.<init>(prefs.java:65)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1130)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2128)
... 11 more
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2137)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
at rare_war.weapons.prefs.<init>(prefs.java:65)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1130)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2128)
... 11 more
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2137)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
at android.content.ContextWrapper.getSharedPreferences(ContextWrapper.java:167)
at rare_war.weapons.prefs.<init>(prefs.java:62)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1130)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2128)
... 11 more
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2137)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
at android.content.ContextWrapper.getSharedPreferences(ContextWrapper.java:167)
at rare_war.weapons.prefs.<init>(prefs.java:62)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1130)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2128)
... 11 more
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2137)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
at android.content.ContextWrapper.getSharedPreferences(ContextWrapper.java:167)
at rare_war.weapons.prefs.<init>(prefs.java:62)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1130)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2128)
... 11 more
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2137)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
at android.content.ContextWrapper.getSharedPreferences(ContextWrapper.java:167)
at rare_war.weapons.prefs.<init>(prefs.java:62)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1130)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2128)
... 11 more
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2137)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
at android.content.ContextWrapper.getSharedPreferences(ContextWrapper.java:167)
at rare_war.weapons.prefs.<init>(prefs.java:62)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1130)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2128)
... 11 more
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2137)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
at android.content.ContextWrapper.getSharedPreferences(ContextWrapper.java:167)
at rare_war.weapons.prefs.<init>(prefs.java:64)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1130)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2128)
... 11 more
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2137)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
at android.content.ContextWrapper.getPackageName(ContextWrapper.java:135)
at android.preference.PreferenceManager.getDefaultSharedPreferencesName(PreferenceManager.java:374)
at android.preference.PreferenceManager.getDefaultSharedPreferences(PreferenceManager.java:369)
at rare_war.weapons.prefs.<init>(prefs.java:66)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1130)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2128)
... 11 more
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2137)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
at android.content.ContextWrapper.getSharedPreferences(ContextWrapper.java:167)
at rare_war.weapons.prefs.<init>(prefs.java:63)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1130)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2128)
... 11 more
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2137)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
at android.content.ContextWrapper.getPackageName(ContextWrapper.java:135)
at android.preference.PreferenceManager.getDefaultSharedPreferencesName(PreferenceManager.java:374)
at android.preference.PreferenceManager.getDefaultSharedPreferences(PreferenceManager.java:369)
at rare_war.weapons.prefs.<init>(prefs.java:65)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1130)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2128)
... 11 more
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2137)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
at android.preference.PreferenceManager.getDefaultSharedPreferencesName(PreferenceManager.java:374)
at android.preference.PreferenceManager.getDefaultSharedPreferences(PreferenceManager.java:369)
at rare_war.weapons.prefs.<init>(prefs.java:68)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1130)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2128)
... 11 more
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2137)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
at android.preference.PreferenceManager.getDefaultSharedPreferencesName(PreferenceManager.java:374)
at android.preference.PreferenceManager.getDefaultSharedPreferences(PreferenceManager.java:369)
at rare_war.weapons.prefs.<init>(prefs.java:68)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1130)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2128)
... 11 more
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2137)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
at android.preference.PreferenceManager.getDefaultSharedPreferencesName(PreferenceManager.java:374)
at android.preference.PreferenceManager.getDefaultSharedPreferences(PreferenceManager.java:369)
at rare_war.weapons.prefs.<init>(prefs.java:68)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1130)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2128)
... 11 more
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2137)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
at android.preference.PreferenceManager.getDefaultSharedPreferencesName(PreferenceManager.java:374)
at android.preference.PreferenceManager.getDefaultSharedPreferences(PreferenceManager.java:369)
at rare_war.weapons.prefs.<init>(prefs.java:75)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1130)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2128)
... 11 more
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2137)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
at android.preference.PreferenceManager.getDefaultSharedPreferencesName(PreferenceManager.java:374)
at android.preference.PreferenceManager.getDefaultSharedPreferences(PreferenceManager.java:369)
at rare_war.weapons.prefs.<init>(prefs.java:74)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1130)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2128)
... 11 more
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2137)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
at android.content.ContextWrapper.getSharedPreferences(ContextWrapper.java:167)
at rare_war.weapons.prefs.<init>(prefs.java:68)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1130)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2128)
... 11 more
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2137)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
at android.content.ContextWrapper.getSharedPreferences(ContextWrapper.java:167)
at rare_war.weapons.prefs.<init>(prefs.java:68)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1130)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2128)
... 11 more
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2137)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
at android.content.ContextWrapper.getSharedPreferences(ContextWrapper.java:167)
at rare_war.weapons.prefs.<init>(prefs.java:68)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1130)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2128)
... 11 more
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2137)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
at android.preference.PreferenceManager.getDefaultSharedPreferencesName(PreferenceManager.java:374)
at android.preference.PreferenceManager.getDefaultSharedPreferences(PreferenceManager.java:369)
at rare_war.weapons.prefs.<init>(prefs.java:75)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1130)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2128)
... 11 more
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2137)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
at android.app.ActivityThread.access$600(ActivityThread.java:141)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5103)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
at android.content.ContextWrapper.getSharedPreferences(ContextWrapper.java:167)
at rare_war.weapons.prefs.<init>(prefs.java:68)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1130)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2128)
... 11 more

My goal is to store the new password from edittextpreference to the
Sharedpreference...
Not a good idea. You shouldn't store passwords on SharedPreferences
I would suggest using a different approach like storing the encrypted password on a server and then check what the user entered against it.
Please, also make sure you read the Android guide on SharedPreferences

Hi you are saving password on sharedPreference named 'data_storage' and retrieving from default sharedPreference thats why you are not getting saved password.Try to save and retrieve preference value from same sharedPreference.

Why don't you use getSharedPreferences for the key "data_storage" and not for getDefaultSharedPreferences, in other words, Context? I'm not really sure about it, but you should try.
The mechanism works as follows: you save the key under a string name "date_storage" then you retrieve they key. In both cases you need to get the SharedPreferences with the line:
SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(Context);
After that use the "sp.get()" methods to get the required value for the saved string key ("data_storage").

Selecting an item in ListFragment list programmatically

I've made my Android app tablet optimized and I followed the tutorial here:
Everything is great, but I am trying to select an item (say, the 1st item) with a button in the ActionBar.
I tried this answer to use performItemClick but on I've got error reports of java.lang.IllegalStateException
in android.support.v4.app.ListFragment.ensureList, java.lang.IllegalStateException: Content view not yet created, and java.lang.NullPointerException
in android.content.ComponentName.<init>
I've tried checking if the ListView is null and still get the error reports on the Play Store. How do I properly select an item in my list programmatically?
Update to add logcat and the code is virtually identical to the tutorials in the links:
Logcat A:
java.lang.IllegalStateException: Content view not yet created
at android.support.v4.app.ListFragment.ensureList(ListFragment.java:328)
at android.support.v4.app.ListFragment.getListView(ListFragment.java:222)
at com.ccwilcox.meteorshower.MeteorList.showMeteorDetails(MeteorList.java:69)
at com.ccwilcox.meteorshower.MeteorList.onListItemClick(MeteorList.java:62)
at android.support.v4.app.ListFragment$2.onItemClick(ListFragment.java:58)
at android.widget.AdapterView.performItemClick(AdapterView.java:298)
at android.widget.AbsListView.performItemClick(AbsListView.java:1280)
at com.ccwilcox.meteorshower.MainActivity.viewUpcomingEvent(MainActivity.java:648)
at com.ccwilcox.meteorshower.MainActivity.onOptionsItemSelected(MainActivity.java:534)
at android.app.Activity.onMenuItemSelected(Activity.java:2606)
at android.support.v4.app.FragmentActivity.onMenuItemSelected(FragmentActivity.java:361)
at com.android.internal.policy.impl.PhoneWindow.onMenuItemSelected(PhoneWindow.java:1045)
at com.android.internal.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:735)
at com.android.internal.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:149)
at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:874)
at com.android.internal.view.menu.ActionMenuView.invokeItem(ActionMenuView.java:592)
at com.android.internal.view.menu.ActionMenuItemView.onClick(ActionMenuItemView.java:149)
at android.view.View.performClick(View.java:4222)
at android.view.View$PerformClick.run(View.java:17273)
at android.os.Handler.handleCallback(Handler.java:615)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4895)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:994)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:761)
at dalvik.system.NativeStart.main(Native Method)
Logcat B:
java.lang.NullPointerException
at android.content.ComponentName.<init>(ComponentName.java:75)
at android.content.Intent.<init>(Intent.java:2874)
at com.ccwilcox.meteorshower.MeteorList.showMeteorDetails(MeteorList.java:86)
at com.ccwilcox.meteorshower.MeteorList.onListItemClick(MeteorList.java:62)
at android.support.v4.app.ListFragment$2.onItemClick(ListFragment.java:58)
at android.widget.AdapterView.performItemClick(AdapterView.java:284)
at android.widget.ListView.performItemClick(ListView.java:3701)
at com.ccwilcox.meteorshower.MainActivity.viewUpcomingEvent(MainActivity.java:648)
at com.ccwilcox.meteorshower.MainActivity.onOptionsItemSelected(MainActivity.java:534)
at android.app.Activity.onMenuItemSelected(Activity.java:2205)
at android.support.v4.app.FragmentActivity.onMenuItemSelected(FragmentActivity.java:361)
at com.android.internal.policy.impl.PhoneWindow.onMenuItemSelected(PhoneWindow.java:779)
at com.android.internal.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:143)
at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:861)
at com.android.internal.view.menu.IconMenuView.invokeItem(IconMenuView.java:532)
at com.android.internal.view.menu.IconMenuItemView.performClick(IconMenuItemView.java:122)
at android.view.View$PerformClick.run(View.java:9152)
at android.os.Handler.handleCallback(Handler.java:587)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:130)
at android.app.ActivityThread.main(ActivityThread.java:3687)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:507)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:842)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
at dalvik.system.NativeStart.main(Native Method)
Update 2
And here is the code that is causing the problem:
if (mListFragment.listView != null) {
mListFragment.listView.performItemClick(mListFragment.listView.getAdapter().getView(position, null, null), position, mListFragment.listView.getAdapter().getItemId(position));
}

android error IllegalArgumentException

I can't find following error in my code. It looks like the problem is in the asynctask onpostexecute.
java.lang.IllegalArgumentException: View not attached to window manager
at android.view.WindowManagerImpl.findViewLocked(WindowManagerImpl.java:672)
at android.view.WindowManagerImpl.removeView(WindowManagerImpl.java:368)
at android.view.WindowManagerImpl$CompatModeWrapper.removeView(WindowManagerImpl.java:160)
at android.app.Dialog.dismissDialog(Dialog.java:319)
at android.app.Dialog.dismiss(Dialog.java:302)
at www.mobilezar.mn.Advertisements$InitialLoading.onPostExecute(Advertisements.java:216)
at www.mobilezar.mn.Advertisements$InitialLoading.onPostExecute(Advertisements.java:1)
at android.os.AsyncTask.finish(AsyncTask.java:631)
at android.os.AsyncTask.access$600(AsyncTask.java:177)
at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:644)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4898)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773)
at dalvik.system.NativeStart.main(Native Method)

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