NullPointerException异常的共享preferences声明Android应用？ [英] NullPointerException in android app on sharedpreferences declaration?
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问题描述
所以，做一个应用程序。我添加新的code加载，而现在FC的开放：（
So, making an app. I added loads of new code, and now it FC's on open :(
下面是logcat的：
Here is the logcat:
07-25 16:59:12.490: D/AndroidRuntime(26121): Shutting down VM
07-25 16:59:12.495: W/dalvikvm(26121): threadid=1: thread exiting with uncaught exception (group=0x40a641f8)
07-25 16:59:12.495: E/AndroidRuntime(26121): FATAL EXCEPTION: main
07-25 16:59:12.495: E/AndroidRuntime(26121): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.liamwli.smsbusy/com.liamwli.smsbusy.Sms_busyActivity}: java.lang.NullPointerException
07-25 16:59:12.495: E/AndroidRuntime(26121): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1993)
07-25 16:59:12.495: E/AndroidRuntime(26121): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2104)
07-25 16:59:12.495: E/AndroidRuntime(26121): at android.app.ActivityThread.access$600(ActivityThread.java:132)
07-25 16:59:12.495: E/AndroidRuntime(26121): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1157)
07-25 16:59:12.495: E/AndroidRuntime(26121): at android.os.Handler.dispatchMessage(Handler.java:99)
07-25 16:59:12.495: E/AndroidRuntime(26121): at android.os.Looper.loop(Looper.java:137)
07-25 16:59:12.495: E/AndroidRuntime(26121): at android.app.ActivityThread.main(ActivityThread.java:4575)
07-25 16:59:12.495: E/AndroidRuntime(26121): at java.lang.reflect.Method.invokeNative(Native Method)
07-25 16:59:12.495: E/AndroidRuntime(26121): at java.lang.reflect.Method.invoke(Method.java:511)
07-25 16:59:12.495: E/AndroidRuntime(26121): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
07-25 16:59:12.495: E/AndroidRuntime(26121): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:556)
07-25 16:59:12.495: E/AndroidRuntime(26121): at dalvik.system.NativeStart.main(Native Method)
07-25 16:59:12.495: E/AndroidRuntime(26121): Caused by: java.lang.NullPointerException
07-25 16:59:12.495: E/AndroidRuntime(26121): at android.preference.PreferenceManager.getDefaultSharedPreferencesName(PreferenceManager.java:371)
07-25 16:59:12.495: E/AndroidRuntime(26121): at android.preference.PreferenceManager.getDefaultSharedPreferences(PreferenceManager.java:366)
07-25 16:59:12.495: E/AndroidRuntime(26121): at com.liamwli.smsbusy.Sms_busyActivity.<init>(Sms_busyActivity.java:23)
07-25 16:59:12.495: E/AndroidRuntime(26121): at java.lang.Class.newInstanceImpl(Native Method)
07-25 16:59:12.495: E/AndroidRuntime(26121): at java.lang.Class.newInstance(Class.java:1319)
07-25 16:59:12.495: E/AndroidRuntime(26121): at android.app.Instrumentation.newActivity(Instrumentation.java:1023)
07-25 16:59:12.495: E/AndroidRuntime(26121): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1984)
07-25 16:59:12.495: E/AndroidRuntime(26121): ... 11 more
07-25 16:59:12.940: I/dalvikvm(26121): threadid=3: reacting to signal 3
07-25 16:59:12.950: I/dalvikvm(26121): Wrote stack traces to '/data/anr/traces.txt'
07-25 16:59:13.040: I/dalvikvm(26121): threadid=3: reacting to signal 3
07-25 16:59:13.045: I/dalvikvm(26121): Wrote stack traces to '/data/anr/traces.txt'
Sms_busyActivity.java的第23行是：
Line 23 of Sms_busyActivity.java is:
SharedPreferences getPrefs = PreferenceManager.getDefaultSharedPreferences(getBaseContext());
我不明白我收到此错误。
I don't understand what I am getting this error.
活动的其余低于（这是相当大的）：
The rest of the activity is below (It is quite large):
package com.liamwli.smsbusy;
import android.app.Activity;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.util.Log;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.CompoundButton;
import android.widget.EditText;
import android.widget.Toast;
import android.widget.ToggleButton;
import android.content.IntentFilter;
import android.content.SharedPreferences;
public class Sms_busyActivity extends Activity {
IntentFilter intentFilter;
ToggleButton endis;
EditText message;
Button smessage;
SharedPreferences getPrefs = PreferenceManager.getDefaultSharedPreferences(getBaseContext());
SharedPreferences.Editor editor = getPrefs.edit();
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Intent i = new Intent("com.liamwli.smsbusy.PREFS");
// startActivity(i);
setContentView(R.layout.main);
endis = (ToggleButton) findViewById(R.id.enableddis);
smessage = (Button) findViewById(R.id.savemess);
message = (EditText) findViewById(R.id.message);
// ---intent to filter for SMS messages received---
intentFilter = new IntentFilter();
intentFilter.addAction("SMS_RECEIVED_ACTION");
endis.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton arg0, boolean arg1) {
// TODO Auto-generated method stub
Toast.makeText(Sms_busyActivity.this, "App state changed",
Toast.LENGTH_LONG).show();
if (endis.isChecked()){
editor.putBoolean("enabled", true);
editor.commit();
}else {
editor.putBoolean("enabled", false);
editor.commit();
}
editor.putString("message", message.getText().toString());
editor.commit();
}
});
smessage.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
editor.putString("message", message.getText().toString());
editor.commit();
}
});
}
@SuppressWarnings("deprecation")
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (Integer.parseInt(android.os.Build.VERSION.SDK) < 5
&& keyCode == KeyEvent.KEYCODE_BACK
&& event.getRepeatCount() == 0) {
Log.d("CDA", "onKeyDown Called");
onBackPressed();
}
return super.onKeyDown(keyCode, event);
}
public void onBackPressed() {
Log.d("CDA", "onBackPressed Called");
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// TODO Auto-generated method stub
return super.onCreateOptionsMenu(menu);
}
}
请有人可以帮我吗？
推荐答案
移动下面的code到的onCreate（）方法中。
Move the following code to within the onCreate() method.
getPrefs = PreferenceManager.getDefaultSharedPreferences(getBaseContext());
其原因是，在现有的code，您使用的上下文（ getBaseContext（））之前，它可以通过调用完全创建 super.onCreate（）。
The reason being, in your existing code, you're using the context (getBaseContext()) before it could be fully created by a call to super.onCreate().
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