I am saving the value in sharedPreferences in one Class and trying to access it from another class but get null pointer exception. the value that i enter is url for web service. please help me.<\/p>\n
UrlSetting.java<\/p>\n
public class UrlSetting extends Activity {\nEditText editUrl;\nTextView Savedurl;\nButton bSaveUrl, bback;\n\n@Override\npublic void onCreate(Bundle savedInstanceState) {\n super.onCreate(savedInstanceState);\n setContentView(R.layout.urlsetting);\n\n Savedurl = (TextView)findViewById(R.id.savedurl);\n editUrl = (EditText)findViewById(R.id.editurl);\n bback = (Button)findViewById(R.id.back);\n bSaveUrl = (Button)findViewById(R.id.saveurl);\n bSaveUrl.setOnClickListener(buttonSaveUrlOnClickListener);\n bback.setOnClickListener(new Button.OnClickListener(){\n\n @Override\n public void onClick(View arg0) {\n \/\/ TODO Auto-generated method stub\n Intent intent = new Intent(UrlSetting.this, Login.class);\n \/*intent.setClass(UrlSetting.this, Login.class);*\/\n startActivity(intent);\n }});\n\n LoadPreferences();\n}\nButton.OnClickListener buttonSaveUrlOnClickListener\n= new Button.OnClickListener(){\n\n @Override\n public void onClick(View arg0) {\n \/\/ TODO Auto-generated method stub\n SavePreferences(\"URL\", editUrl.getText().toString());\n LoadPreferences();\n }\n\nprivate void SavePreferences(String key, String value){\n SharedPreferences sharedPreferences = getSharedPreferences(\"MY_SHARED_PREF\", MODE_PRIVATE);\n SharedPreferences.Editor editor = sharedPreferences.edit();\n editor.putString(key, value);\n editor.commit();\n}\n\nprivate void LoadPreferences(){\n SharedPreferences sharedPreferences = getSharedPreferences(\"MY_SHARED_PREF\", MODE_PRIVATE);\n String strSavedurl = sharedPreferences.getString(\"URL\", \"\");\n Savedurl.setText(strSavedurl);\n}\n<\/code><\/pre>\nand this is my Koneksi.java<\/p>\n
public class Koneksi{\n\nSharedPreferences sharedPreferences = getSharedPreferences(\"MY_SHARED_PREF\", MODE_PRIVATE);\nString url = sharedPreferences.getString(\"URL\", \"\");\npublic Koneksi(String urlml){\n\n url= url + urlml;\n}\n\npublic String getUrl(){\n\n return url;\n}\n<\/code><\/pre>\nthis is the LogCat<\/p>\n
> 05-21 11:39:44.542: W\/KeyCharacterMap(339): No keyboard for id 0\n05-21 11:39:44.542: W\/KeyCharacterMap(339): Using default keymap: \/system\/usr\/keychars\/qwerty.kcm.bin\n05-21 11:39:51.826: D\/TryLoginCheck(339): Here\n05-21 11:39:51.826: I\/System.out(339): UserNametes\n05-21 11:39:51.831: I\/System.out(339): passwordTes12345*\n05-21 11:39:51.831: D\/Parameters(339): username=tes&password=Tes12345*\n05-21 11:39:51.831: D\/AndroidRuntime(339): Shutting down VM\n05-21 11:39:51.831: W\/dalvikvm(339): threadid=1: thread exiting with uncaught exception (group=0x40015560)\n05-21 11:39:51.851: E\/AndroidRuntime(339): FATAL EXCEPTION: main\n05-21 11:39:51.851: E\/AndroidRuntime(339): java.lang.NullPointerException\n05-21 11:39:51.851: E\/AndroidRuntime(339): at android.content.ContextWrapper.getSharedPreferences(ContextWrapper.java:146)\n05-21 11:39:51.851: E\/AndroidRuntime(339): at mobile.config.Koneksi.(Koneksi.java:13)\n05-21 11:39:51.851: E\/AndroidRuntime(339): at com.karismaelearning.Login.tryLogin(Login.java:131)\n05-21 11:39:51.851: E\/AndroidRuntime(339): at com.karismaelearning.Login$3.onClick(Login.java:80)\n05-21 11:39:51.851: E\/AndroidRuntime(339): at android.view.View.performClick(View.java:2485)\n05-21 11:39:51.851: E\/AndroidRuntime(339): at android.view.View$PerformClick.run(View.java:9080)\n05-21 11:39:51.851: E\/AndroidRuntime(339): at android.os.Handler.handleCallback(Handler.java:587)\n05-21 11:39:51.851: E\/AndroidRuntime(339): at android.os.Handler.dispatchMessage(Handler.java:92)\n05-21 11:39:51.851: E\/AndroidRuntime(339): at android.os.Looper.loop(Looper.java:123)\n05-21 11:39:51.851: E\/AndroidRuntime(339): at android.app.ActivityThread.main(ActivityThread.java:3683)\n05-21 11:39:51.851: E\/AndroidRuntime(339): at java.lang.reflect.Method.invokeNative(Native Method)\n05-21 11:39:51.851: E\/AndroidRuntime(339): at java.lang.reflect.Method.invoke(Method.java:507)\n05-21 11:39:51.851: E\/AndroidRuntime(339): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)\n05-21 11:39:51.851: E\/AndroidRuntime(339): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)\n05-21 11:39:51.851: E\/AndroidRuntime(339): at dalvik.system.NativeStart.main(Native Method)\n05-21 11:39:54.301: I\/Process(339): Sending signal. PID: 339 SIG: 9\n<\/code><\/pre>\nplease help me to know what the mistake is. I don’t understand what’s wrong. thank you very much<\/p>\n
\n- \n
try this way:<\/p>\n
SharedPreferences sharedPreferences;\n\nonCreate(Bundle savedInstanceState){\n sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);\n \/\/ your code..\n}\n\nprivate void SavePreferences(String key, String value){\n\n SharedPreferences.Editor editor = sharedPreferences.edit();\n editor.putString(key, value);\n editor.commit();\n}\n\nprivate void LoadPreferences(){\n\n String strSavedurl = sharedPreferences.getString(\"URL\", \"\");\n Savedurl.setText(strSavedurl);\n}\n<\/code><\/pre>\nEdited:<\/p>\n
public class Koneksi{\n\n SharedPreferences sharedPreferences;\n Context myC;\n String url = \"\";\n\n public Koneksi(Context con){\n myC = con;\n sharedPreferences = PreferenceManager.getDefaultSharedPreferences(con);\n }\n\n\n public Koneksi(String urlml){\n\n url= url + urlml;\n }\n\n\n public String getUrl(){\n String url = sharedPreferences.getString(\"URL\", \"\");\n return url;\n }\n}\n<\/code><\/pre>\nfor call above class from activity:<\/p>\n
Koneksi ob = new Koneksi(this);\nString URL = ob.getUrl();\n<\/code><\/pre>\n<\/li>\n- \n
try these two methods :p works well<\/p>\n
public static void SavePreferences(String key, String name, String value,Context c) {\n SharedPreferences sf = c.getSharedPreferences(key, 0);\n SharedPreferences.Editor editor = sf.edit();\n editor.putString(name, value);\n editor.commit();\n Log.w(\"Preference saved .\", value);\n\n}\n\npublic static String LoadPreferences(String key, String name, Context c) {\n SharedPreferences sf = c.getSharedPreferences(key, 0);\n String val = null;\n val = sf.getString(name, \"\");\n return val;\n\n}\n<\/code><\/pre>\n<\/li>\n- \n
- you should be pass the context \n\n\n\n mContext.getSharedPreferences(PREF_NAME, MODE_PRIVATE);\n\n\n\n\n other wise use following code :-\n import android.preference.PreferenceManager;\n SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);\n \/\/ then you use\n prefs.getBoolean(\"keystring\", true);\n<\/code><\/pre>\n<\/li>\n- \n
These will give you NPE<\/code><\/p>\nSharedPreferences sharedPreferences = getSharedPreferences(\"MY_SHARED_PREF\", MODE_PRIVATE); \nString url = sharedPreferences.getString(\"URL\", \"\");\n<\/code><\/pre>\nMove the initializations to onCreate()<\/code> which I don’t see but assuming you have since you are extending Activity<\/code><\/p>\npublic class Koneksi extends Activity {\n\n SharedPreferences sharedPreferences; \/\/declare them here\n String url;\n\n public void onCreate(Bundle bundle)\n {\n super.onCreate(bundle);\n setContentView(R.layout.your_layout);\n\n sharedPreferences = getSharedPreferences(\"MY_SHARED_PREF\", MODE_PRIVATE); \/\/ initialize them here\n url = sharedPreferences.getString(\"URL\", \"\"); \/\/ intialize here\n\n public Koneksi(String urlml){ \n url= url + urlml;\n }\n<\/code><\/pre>\nSharedPreferences<\/code> needs a Context<\/code> which isn’t available until after onCreate()<\/code> is called. You can declare them before this as you are but you need to initialize them in onCreate()<\/code> or another Activity<\/code> method after onCreate()<\/code>is called<\/p>\n<\/li>\n- \n
i dont know what is the problem with your code, i have working implementation for same..<\/p>\n
public class GreetingCardData {\n public static final String SHARED_PREF_FILE = \"greetingCardData\";\n public static final String KEY_DO_NOT_SHOW = \"doNotShow\";\n public static final String KEY_CATEGORIES_JSON = \"categoriesJson\"; \n private SharedPreferences sharedPrefs;\n private Editor prefsEditor;\n\n public GreetingCardData(Context context) {\n this.sharedPrefs = context.getSharedPreferences(SHARED_PREF_FILE, 0);\n this.prefsEditor = sharedPrefs.edit();\n } \n\n public void setDoNotShowFlag ( boolean flag ){\n prefsEditor.putBoolean( KEY_DO_NOT_SHOW, flag );\n prefsEditor.commit();\n }\n\n public boolean getDoNotShowFlag(){\n return sharedPrefs.getBoolean( KEY_DO_NOT_SHOW, false );\n }\n\n public void setGreetingcardJson( String jsonString ){\n prefsEditor.putString( KEY_CATEGORIES_JSON, jsonString );\n prefsEditor.commit();\n }\n\n public String getGreetingcardJsonString(){\n return sharedPrefs.getString(KEY_CATEGORIES_JSON, \"\");\n } \n}\n<\/code><\/pre>\nand you can access your pref. anywhere by just calling it like..<\/p>\n
if( !new GreetingCardData(ActivityMain.this).getDoNotShowFlag())\n startHomeActivity(); \n\n\nnew GreetingCardData(context).setGreetingcardJson(resBuffer.toString());\n<\/code><\/pre>\n<\/li>\n<\/ol>\nOriginally posted 2013-11-16 20:50:26. <\/small><\/p>","protected":false},"excerpt":{"rendered":"
I am saving the value in sharedPreferences in one Class and trying to access it from another class but get null pointer exception. the value that i enter is url for web service. please help me. UrlSetting.java public class UrlSetting extends Activity { EditText editUrl; TextView Savedurl; Button bSaveUrl, bback; @Override public void onCreate(Bundle savedInstanceState) […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-1425","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts\/1425","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/comments?post=1425"}],"version-history":[{"count":0,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts\/1425\/revisions"}],"wp:attachment":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/media?parent=1425"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/categories?post=1425"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/tags?post=1425"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}