good morning, I was trying the SharedPreferences Class and I have created two classes, “TestingActivity”, extending android.app.Activity and AccountSettings with two static functions to set and recover a KEY from SharedPreferences.
I am having this error while running Intent from the main activity:
01-12 17:18:47.890: E/AndroidRuntime(5539): FATAL EXCEPTION: main
01-12 17:18:47.890: E/AndroidRuntime(5539): java.lang.RuntimeException: Unable to start activity ComponentInfo{es.LandeSoft/es.LandeSoft.TestingActivity}: java.lang.NullPointerException
01-12 17:18:47.890: E/AndroidRuntime(5539): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1651)
01-12 17:18:47.890: E/AndroidRuntime(5539): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1667)
01-12 17:18:47.890: E/AndroidRuntime(5539): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
01-12 17:18:47.890: E/AndroidRuntime(5539): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:935)
01-12 17:18:47.890: E/AndroidRuntime(5539): at android.os.Handler.dispatchMessage(Handler.java:99)
01-12 17:18:47.890: E/AndroidRuntime(5539): at android.os.Looper.loop(Looper.java:130)
01-12 17:18:47.890: E/AndroidRuntime(5539): at android.app.ActivityThread.main(ActivityThread.java:3691)
01-12 17:18:47.890: E/AndroidRuntime(5539): at java.lang.reflect.Method.invokeNative(Native Method)
01-12 17:18:47.890: E/AndroidRuntime(5539): at java.lang.reflect.Method.invoke(Method.java:507)
01-12 17:18:47.890: E/AndroidRuntime(5539): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:907)
01-12 17:18:47.890: E/AndroidRuntime(5539): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:665)
01-12 17:18:47.890: E/AndroidRuntime(5539): at dalvik.system.NativeStart.main(Native Method)
01-12 17:18:47.890: E/AndroidRuntime(5539): Caused by: java.lang.NullPointerException
01-12 17:18:47.890: E/AndroidRuntime(5539): at es.LandeSoft.TestingActivity.onCreate(TestingActivity.java:30)
01-12 17:18:47.890: E/AndroidRuntime(5539): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
01-12 17:18:47.890: E/AndroidRuntime(5539): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1615)
01-12 17:18:47.890: E/AndroidRuntime(5539): ... 11 more
Im starting the activity from the main Activity launcher with this code:
Intent intent= new Intent(this,TestingActivity.class);
startActivity(intent);</i>
The Activity Class is real simple and it’s the following:
package es.LandeSoft;
import es.LandeSoft.R;
import android.app.Activity;
import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class TestingActivity extends Activity {
TextView lblDatos=null;
EditText DatosAGuardar =null;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
Button botonGuardar = (Button) findViewById(R.id.btnGuardar);
Button botonRecuperar = (Button) findViewById(R.id.btnRecuperar);
lblDatos = (TextView) findViewById(R.id.textView1);
DatosAGuardar= (EditText) findViewById(R.id.txtPref);
botonGuardar.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
AccountSettings.SavePassword(getApplicationContext(),"PASSWORD_APP",DatosAGuardar.getText().toString());
ShowToast("Se ha guardado el password: " + DatosAGuardar.getText().toString() , 2500);
}
});
botonRecuperar.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
String clave= AccountSettings.GetPassword(getApplicationContext(), "PASSWORD_APP");
lblDatos.setText(clave);
ShowToast("Clave Recuperada: " + clave,2000);
}
});
}
private void ShowToast(String MessageT, int Duracion)
{
Toast miTostada= new Toast(getApplicationContext());
miTostada.setText(MessageT);
miTostada.setDuration(Duracion);
miTostada.setGravity(Gravity.CENTER,0,0);
miTostada.show();
}
}
**The AccountSettings.java is the following:**
package es.LandeSoft;
import android.content.Context;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
public class AccountSettings {
public static String GetPassword (Context Contexto, String Key)
{
SharedPreferences savedSession= Contexto.getSharedPreferences(Key,Context.MODE_PRIVATE);
return savedSession.getString(Key, null);
}
public static void SavePassword(Context context, String Key, String Value)
{
Editor editor = context.getSharedPreferences(Key,Context.MODE_PRIVATE).edit();
editor.putString(Key, Value);
}
}
The TestingActivity XML is the following:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/TextViewInfo"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/TextViewInfo_Text" />
<EditText
android:id="@+id/txtPref"
android:inputType="text"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<requestFocus />
</EditText>
<Button
android:id="@+id/btnGuardar"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/btn_guardar" />
<Button
android:id="@+id/btnRecuperar"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/btn_recuperar" />
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
</LinearLayout>
and The Android Manifest:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="es.LandeSoft"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="8" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.UPDATE_DEVICE_STATS"/>
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="android.permission.INTERNET"/>
<application android:label="@string/app_name"
android:debuggable="true"
android:icon="@drawable/landesofticon">
<activity android:name="es.LandeSoft.LandeSoftActivity"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name="es.LandeSoft.FacebookClass"></activity>
<activity android:name="es.LandeSoft.TestingActivity"></activity>
</application>
</manifest>
I dont understand why the OnCreate Method is crashing, can someone give me a clue?
Thanks in advance!
I cannot see your
R.layout.mainfor your layout or yourTestingActivity.xmlbeing called. Check for that