Question

在Android模拟器上运行项目时，我在getApplicationContext上面对异常，因为java.lang.NullPointerException。请帮我解决这个问题。

错误

07-19 15:08:07.811: D/AndroidRuntime(366): Shutting down VM
07-19 15:08:07.811: W/dalvikvm(366): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
07-19 15:08:07.841: E/AndroidRuntime(366): FATAL EXCEPTION: main
07-19 15:08:07.841: E/AndroidRuntime(366): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{org.TfsMutualFund/org.TfsMutualFund.loading}: java.lang.NullPointerException
07-19 15:08:07.841: E/AndroidRuntime(366):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2585)
07-19 15:08:07.841: E/AndroidRuntime(366):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)

07-19 15:08:07.841: E/AndroidRuntime(366): Caused by: java.lang.NullPointerException
07-19 15:08:07.841: E/AndroidRuntime(366):  at android.content.ContextWrapper.getApplicationContext(ContextWrapper.java:100)
07-19 15:08:07.841: E/AndroidRuntime(366):  at org.TfsMutualFund.loading.<init>(loading.java:23)

的AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
 package="org.TfsMutualFund">   
<uses-sdk android:targetSdkVersion="8" />

<application android:name=".globalAdapter" android:icon="@drawable/icon" android:label="@string/app_name">

    <activity android:name=".loading"
              android:label="@string/app_name"
              android:theme="@android:style/Theme.NoTitleBar"
              android:configChanges="orientation|keyboard|keyboardHidden">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity android:name=".TFSManinActivity"
    android:configChanges="orientation|keyboard|keyboardHidden"/>
</application>

loading.java

package org.TfsMutualFund;

public class loading extends Activity{
private static ArrayAdapter<String> adapter;
private globalAdapter adpt = ((globalAdapter)getApplicationContext());
private String ServicePath = adpt.getServicePath();
private String ServiceName = adpt.getServiceName();
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.loading);
 if(isOnline())
    new AsyncLoad().execute();
 else

Answer 1

不要在OnCreate()之前初始化它，你不能在那里得到Context，在onCreate()中执行。

private globalAdapter adpt;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.loading);
    adpt  = ((globalAdapter)getApplicationContext());
    ...
}

Answer 2

1。在onCreate之前不要初始化以下内容，让视图首先获取其ID

private globalAdapter adpt = ((globalAdapter)getApplicationContext());
private String ServicePath = adpt.getServicePath();
private String ServiceName = adpt.getServiceName();

2。只是声明他们......

private globalAdapter adpt;
private String ServicePath;  
private String ServiceName;

3。这是因为当Activity没有形成时，如何让Context获得该活动，因为你使用getApplicationContext()来获取当前的Activity上下文。

启动适配器时，getapplicationContext（）中的Java.lang.NullPointerException

2 个答案: