java - NullPointerException:没有给出应用程序实例，getinstance() 甚至 this(!?) 似乎返回 null

Question

为什么变量application返回null，抛出空指针异常？我正在尝试修改 KP Android 应用程序，但无法通过登录屏幕，因为它会抛出此错误。

08-07 23:55:51.229: E/AndroidRuntime(14870): FATAL EXCEPTION: main
08-07 23:55:51.229: E/AndroidRuntime(14870): Process: com.bernard.beaconportal.activities, PID: 14870
08-07 23:55:51.229: E/AndroidRuntime(14870): java.lang.NullPointerException: No application instance given
08-07 23:55:51.229: E/AndroidRuntime(14870):    at com.bernard.beaconportal.activities.mail.store.StorageManager.<init>(StorageManager.java:525)
08-07 23:55:51.229: E/AndroidRuntime(14870):    at com.bernard.beaconportal.activities.mail.store.StorageManager.getInstance(StorageManager.java:497)
08-07 23:55:51.229: E/AndroidRuntime(14870):    at com.bernard.beaconportal.activities.Account.<init>(Account.java:272)
08-07 23:55:51.229: E/AndroidRuntime(14870):    at com.bernard.beaconportal.activities.Preferences.newAccount(Preferences.java:113)
08-07 23:55:51.229: E/AndroidRuntime(14870):    at com.bernard.beaconportal.activities.activity.setup.AccountSetupBasics.onManualSetup(AccountSetupBasics.java:309)
08-07 23:55:51.229: E/AndroidRuntime(14870):    at com.bernard.beaconportal.activities.activity.setup.AccountSetupBasics.onNext(AccountSetupBasics.java:272)
08-07 23:55:51.229: E/AndroidRuntime(14870):    at com.bernard.beaconportal.activities.activity.setup.AccountSetupBasics.onClick(AccountSetupBasics.java:349)
08-07 23:55:51.229: E/AndroidRuntime(14870):    at android.view.View.performClick(View.java:4466)
08-07 23:55:51.229: E/AndroidRuntime(14870):    at android.view.View$PerformClick.run(View.java:18827)
08-07 23:55:51.229: E/AndroidRuntime(14870):    at android.os.Handler.handleCallback(Handler.java:808)
08-07 23:55:51.229: E/AndroidRuntime(14870):    at android.os.Handler.dispatchMessage(Handler.java:103)
08-07 23:55:51.229: E/AndroidRuntime(14870):    at android.os.Looper.loop(Looper.java:193)
08-07 23:55:51.229: E/AndroidRuntime(14870):    at android.app.ActivityThread.main(ActivityThread.java:5299)
08-07 23:55:51.229: E/AndroidRuntime(14870):    at java.lang.reflect.Method.invokeNative(Native Method)
08-07 23:55:51.229: E/AndroidRuntime(14870):    at java.lang.reflect.Method.invoke(Method.java:515)
08-07 23:55:51.229: E/AndroidRuntime(14870):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:836)
08-07 23:55:51.229: E/AndroidRuntime(14870):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:652)
08-07 23:55:51.229: E/AndroidRuntime(14870):    at de.robv.android.xposed.XposedBridge.main(XposedBridge.java:132)
08-07 23:55:51.229: E/AndroidRuntime(14870):    at dalvik.system.NativeStart.main(Native Method)

现在这里是 logcat 中引用的行:

K9.app初始化的地方，抱歉之前没贴出来

/**
     * Register a component to be notified when the {@link K9} instance is ready.
     *
     * @param component
     *            Never <code>null</code>.
     */
    public static void registerApplicationAware(final ApplicationAware component) {
        synchronized (observers) {
            if (sInitialized) {
                component.initializeComponent(K9.app);
            } else if (!observers.contains(component)) {
                observers.add(component);
            }
        }
    }

存储管理器中的第 517-526 行

/**
     * @param application
     *            Never <code>null</code>.
     * @throws NullPointerException
     *             If <tt>application</tt> is <code>null</code>.
     */
    protected StorageManager(final Application application) throws NullPointerException {
        if (application == null) {
            throw new NullPointerException("No application instance given");
        }

存储管理器中的第 495-500 行

public static synchronized StorageManager getInstance(final Application application) {
        if (instance == null) {
            instance = new StorageManager(application);
        }
        return instance;
    }

帐户中的第 272 行

mLocalStorageProviderId = StorageManager.getInstance(K9.app).getDefaultProviderId();

首选项中的第 112-118 行

public synchronized Account newAccount() {
        newAccount = new Account(K9.app);
        accounts.put(newAccount.getUuid(), newAccount);
        accountsInOrder.add(newAccount);

        return newAccount;
    }

AccountSetupBasics 中的第 308-310 行

if (mAccount == null) {
            mAccount = Preferences.getPreferences(this).newAccount();
        }

AccountSetupBasics 中的第 262-274 行

protected void onNext() {
        String email = mEmailView.getText().toString();
        String[] emailParts = splitEmail(email);
        String domain = emailParts[1];
        mProvider = findProviderForDomain(domain);
        if (mProvider == null) {
            /*
             * We don't have default settings for this account, start the manual
             * setup process.
             */
            onManualSetup();
            return;
        }

AccountSetupBasics 中的第 346-355 行

public void onClick(View v) {
        switch (v.getId()) {
        case R.id.next:
            onNext();
            break;
        case R.id.manual_setup:
            onManualSetup();
            break;
        }
    }

这是 android list ，因为我很确定这就是我的问题的根源，因为它似乎是应用程序无法获取名称或包，或者当前正在运行的 Activity ......类似的东西

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"


    package="com.bernard.beaconportal.activities"
    android:versionCode="1"
    android:versionName="1.0"
    >

    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>
    <uses-permission android:name="android.permission.READ_CONTACTS"/>
    <uses-permission android:name="android.permission.READ_SYNC_SETTINGS"/>

    <!-- Needed to mark a contact as contacted -->
    <uses-permission android:name="android.permission.WRITE_CONTACTS"/>

    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
    <uses-permission android:name="android.permission.INTERNET"/>
    <uses-permission android:name="android.permission.VIBRATE"/>
    <uses-permission android:name="android.permission.WAKE_LOCK"/>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

    <uses-permission android:name="org.thialfihar.android.apg.permission.READ_KEY_DETAILS" />

    <permission android:name="com.bernard.beaconportal.activities.permission.READ_ATTACHMENT"
                android:permissionGroup="android.permission-group.MESSAGES"
                android:protectionLevel="dangerous"
                android:label="@string/read_attachment_label"
                android:description="@string/read_attachment_desc"/>
    <uses-permission android:name="com.bernard.beaconportal.activities.permission.READ_ATTACHMENT"/>
    <permission android:name="com.bernard.beaconportal.activities.permission.REMOTE_CONTROL"
                 android:permissionGroup="android.permission-group.MESSAGES"
                 android:protectionLevel="dangerous"
                 android:label="@string/remote_control_label"
                 android:description="@string/remote_control_desc"/>
    <uses-permission android:name="com.bernard.beaconportal.activities.permission.REMOTE_CONTROL"/>
    <permission android:name="com.bernard.beaconportal.activities.permission.READ_MESSAGES"
                android:permissionGroup="android.permission-group.MESSAGES"
                android:protectionLevel="dangerous"
                android:label="@string/read_messages_label"
                android:description="@string/read_messages_desc"/>
    <uses-permission android:name="com.bernard.beaconportal.activities.permission.READ_MESSAGES"/>
    <permission android:name="com.bernard.beaconportal.activities.permission.DELETE_MESSAGES"
                android:permissionGroup="android.permission-group.MESSAGES"
                android:protectionLevel="dangerous"
                android:label="@string/delete_messages_label"
                android:description="@string/delete_messages_desc"/>
    <uses-permission android:name="com.bernard.beaconportal.activities.permission.DELETE_MESSAGES"/>
    <uses-feature android:name="android.hardware.touchscreen" android:required="false"/>

     <supports-screens
        android:largeScreens="true"
        android:normalScreens="true"
        android:smallScreens="true"
        android:anyDensity="true"
    />

    <uses-sdk
        android:minSdkVersion="14"
        android:targetSdkVersion="19" />

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/Theme.Sherlock.Light.DarkActionBar" 
        android:allowTaskReparenting="false"


        >
        <meta-data android:name="android.app.default_searchable"
                   android:value=".activity.Search" />


        <activity android:name=".MainActivity" 
            android:theme="@style/CustomActionBarTheme"
            android:windowSoftInputMode="adjustPan"
            >

            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>

        </activity>


        <activity
        android:name=".FragmentsLinked"
        android:theme="@style/CustomActionBarTheme"
        android:windowSoftInputMode="adjustResize"
        >

           </activity>


          <activity

        android:name=".FragmentsEdit"
        android:theme="@style/CustomActionBarTheme"
        android:windowSoftInputMode="adjustResize" >

        </activity>

        <activity  
         android:name=".homeworkdueDetailsActivity"
         android:theme="@style/CustomActionBarTheme"
         android:parentActivityName="com.bernard.beaconportal.activities.MainActivity"
        >


        <!-- Parent activity meta-data to support 4.0 and lower -->
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value="com.bernard.beaconportal.activities.MainActivity" />

        </activity>



        <activity
            android:name=".activity.Accounts"
            android:configChanges="locale"
            android:launchMode="singleTop"
            android:uiOptions="splitActionBarWhenNarrow"
            android:label="@string/app_name">
            <intent-filter>

                <category android:name="android.intent.category.DEFAULT" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
            <intent-filter>
                <action android:name="android.intent.action.VIEW" />
                <data android:mimeType="application/x-k9settings" />
                <category android:name="android.intent.category.DEFAULT" />
                <category android:name="android.intent.category.BROWSABLE" />
            </intent-filter>
        </activity>

        <activity
            android:name=".activity.setup.Prefs"
            android:label="@string/prefs_title"
            android:configChanges="locale"
            android:taskAffinity="com.bernard.beaconportal.activities.activity.setup.Prefs"
            android:excludeFromRecents="true"
            >
        </activity>
        <activity
            android:name=".activity.setup.WelcomeMessage"
            android:label="@string/welcome_message_title"
            android:configChanges="locale"
            >
        </activity>
        <activity
            android:name=".activity.setup.FontSizeSettings"
            android:label="@string/font_size_settings_title"
            android:configChanges="locale"
            >
        </activity>
        <activity
            android:name=".activity.setup.AccountSetupBasics"
            android:label="@string/account_setup_basics_title"
            android:configChanges="locale"
            >
        </activity>
        <activity
            android:name=".activity.setup.AccountSetupAccountType"
            android:label="@string/account_setup_account_type_title"
            android:configChanges="locale"
            >
        </activity>
        <activity
            android:name=".activity.setup.AccountSetupIncoming"
            android:label="@string/account_setup_incoming_title"
            android:configChanges="locale"
            >
        </activity>
        <activity
            android:name=".activity.setup.AccountSetupComposition"
            android:label="@string/account_settings_composition_title"
            android:configChanges="locale"
        >
        </activity>
        <activity
            android:name=".activity.setup.AccountSetupOutgoing"
            android:label="@string/account_setup_outgoing_title"
            android:configChanges="locale"
            >
        </activity>
        <activity
            android:name=".activity.setup.AccountSetupOptions"
            android:label="@string/account_setup_options_title"
            android:configChanges="locale"
            >
        </activity>
        <activity
            android:name=".activity.setup.AccountSetupNames"
            android:label="@string/account_setup_names_title"
            android:configChanges="locale"
            >
        </activity>
        <activity
            android:name=".activity.ChooseFolder"
            android:theme="@style/Theme.K9Dialog"
            android:label="@string/choose_folder_title"
            android:configChanges="locale"
            android:noHistory="true"
            >
        </activity>
        <activity
            android:name=".activity.ChooseIdentity"
            android:theme="@style/Theme.K9Dialog"
            android:label="@string/choose_identity_title"
            android:configChanges="locale"
            >
        </activity>
        <activity
            android:name=".activity.ManageIdentities"
            android:label="@string/manage_identities_title"
            android:configChanges="locale"
            >
        </activity>
        <activity
            android:name=".activity.EditIdentity"
            android:label="@string/edit_identity_title"
            android:configChanges="locale"
            >
        </activity>
        <activity
            android:name=".activity.NotificationDeleteConfirmation"
            android:theme="@android:style/Theme.Translucent.NoTitleBar"
            android:launchMode="singleTop"
            android:taskAffinity=""
            android:excludeFromRecents="true"
            >
        </activity>
        <!-- XXX Note: this activity is hacked to ignore config changes,
             since it doesn't currently handle them correctly in code. -->
        <activity
            android:name=".activity.setup.AccountSetupCheckSettings"
            android:label="@string/account_setup_check_settings_title"
            android:configChanges="keyboardHidden|orientation|locale"
            >
        </activity>
        <activity
            android:name=".activity.setup.AccountSettings"
            android:label="@string/account_settings_title_fmt"
            android:configChanges="locale"
            >
        </activity>

        <activity
            android:name=".activity.setup.FolderSettings"
            android:theme="@android:style/Theme.Dialog"
            android:label="@string/folder_settings_title"
            android:configChanges="locale"
            >
        </activity>
        <activity
            android:name=".activity.FolderList"
            android:configChanges="locale"
            android:uiOptions="splitActionBarWhenNarrow"
            >
            <intent-filter>
                <!-- This action is only to allow an entry point for launcher shortcuts -->

            </intent-filter>
        </activity>
        <activity
            android:name=".activity.MessageList"
            android:configChanges="locale"
            android:launchMode="singleTop"
            android:uiOptions="splitActionBarWhenNarrow"
            >
            <intent-filter>
                <!-- This action is only to allow an entry point for launcher shortcuts -->

            </intent-filter>
            <intent-filter>
                <action android:name="android.intent.action.VIEW" />
                <data
                    android:scheme="email"
                    android:host="messages"
                />
                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>
        <activity
            android:name=".activity.MessageCompose"
            android:label="@string/app_name"
            android:enabled="false"
            android:configChanges="locale"
            >
            <intent-filter>
                <action android:name="android.intent.action.SENDTO" />
                <data android:scheme="mailto" />
                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
            <intent-filter>
                <action android:name="android.intent.action.SEND" />
                <data android:mimeType="*/*" />
                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
            <intent-filter>
                <action android:name="android.intent.action.SEND_MULTIPLE" />
                <data android:mimeType="*/*" />
                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
            <intent-filter>
                <action android:name="android.intent.action.VIEW" />
                <data android:scheme="mailto" />
                <category android:name="android.intent.category.DEFAULT" />
                <category android:name="android.intent.category.BROWSABLE" />
            </intent-filter>
        </activity>
        <!-- Search Activity - searchable -->
        <activity android:name=".activity.Search"
                  android:label="@string/search_action"
                  android:configChanges="locale"
                  android:uiOptions="splitActionBarWhenNarrow"
                  >
            <intent-filter>
                <action android:name="android.intent.action.SEARCH" />
                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
            <meta-data android:name="android.app.searchable"
                       android:resource="@xml/searchable" />
        </activity>
        <activity
            android:name=".activity.LauncherShortcuts"
            android:label="@string/shortcuts_title"
            android:configChanges="locale"
            >
            <intent-filter>
                <action android:name="android.intent.action.CREATE_SHORTCUT" />
                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>
        <activity
            android:name=".activity.AccessibleEmailContentActivity"
            >
        </activity>
        <activity android:name=".activity.EmailAddressList"
            android:configChanges="locale"
            >
        </activity>
        <receiver android:name=".service.BootReceiver"
              android:enabled="true"
              >
            <intent-filter>
                <action android:name="android.intent.action.BOOT_COMPLETED" />
            </intent-filter>
            <intent-filter>
                <action android:name="android.intent.action.DEVICE_STORAGE_LOW" />
            </intent-filter>
            <intent-filter>
                <action android:name="android.intent.action.DEVICE_STORAGE_OK" />
            </intent-filter>
            <intent-filter>
                <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
            </intent-filter>
            <intent-filter>
                <action android:name="android.net.conn.BACKGROUND_DATA_SETTING_CHANGED" />
            </intent-filter>
            <intent-filter>
                <action android:name="com.android.sync.SYNC_CONN_STATUS_CHANGED" />
            </intent-filter>
              <intent-filter>
                <action android:name="com.bernard.beaconportal.activities.service.BroadcastReceiver.scheduleIntent"/>
            </intent-filter>
        </receiver>
        <receiver android:name=".service.RemoteControlReceiver"
               android:enabled="true"
               android:permission="com.bernard.beaconportal.activities.permission.REMOTE_CONTROL"
               >
               <intent-filter>
                 <action android:name="com.bernard.beaconportal.activities.K9RemoteControl.set"/>

             </intent-filter>
             <intent-filter>
                <action android:name="com.bernard.beaconportal.activities.K9RemoteControl.requestAccounts"/>

             </intent-filter>
         </receiver>
        <receiver android:name=".service.CoreReceiver"
              android:enabled="true"
              >
              <intent-filter>
                <action android:name="com.bernard.beaconportal.activities.service.CoreReceiver.wakeLockRelease"/>
            </intent-filter>
        </receiver>
        <receiver android:name=".service.StorageReceiver"
              android:enabled="true"
              >
            <intent-filter>
<!--
android.intent.action.MEDIA_MOUNTED

     * Broadcast Action:  External media is present and mounted at its mount point.
     * The path to the mount point for the removed media is contained in the Intent.mData field.
     * The Intent contains an extra with name "read-only" and Boolean value to indicate if the
     * media was mounted read only.

 -->
                <action android:name="android.intent.action.MEDIA_MOUNTED"/>
<!--

MEDIA_EJECT and MEDIA_UNMOUNTED are not defined here: they have to be dynamically registered
otherwise it would make K-9 start at the wrong time

 -->
                <data android:scheme="file"/>
            </intent-filter>
        </receiver>
        <service
            android:name=".service.MailService"
            android:enabled="true"
            >
        </service>
        <service
            android:name=".service.NotificationActionService"
            android:enabled="true"
            >
        </service>
        <service
             android:name=".service.PushService"
             android:enabled="true"
             >
         </service>
         <service
             android:name=".service.PollService"
             android:enabled="true"
            >
         </service>
         <service
              android:name=".service.RemoteControlService"
              android:enabled="true"
              android:permission="com.bernard.beaconportal.activities.permission.REMOTE_CONTROL"
             >
          </service>
         <service
             android:name=".service.SleepService"
             android:enabled="true"
             >
         </service>
        <provider
            android:name=".provider.AttachmentProvider"
            android:authorities="com.bernard.beaconportal.activities.attachmentprovider"
            android:multiprocess="true"
            android:grantUriPermissions="true"
            android:readPermission="com.bernard.beaconportal.activities.permission.READ_ATTACHMENT"
            android:exported="true"
            />
        <provider
            android:name=".provider.MessageProvider"
            android:authorities="com.bernard.beaconportal.activities.messageprovider"
            android:multiprocess="true"
            android:grantUriPermissions="true"
            android:readPermission="com.bernard.beaconportal.activities.permission.READ_MESSAGES"
            android:writePermission="com.bernard.beaconportal.activities.permission.DELETE_MESSAGES"
            android:exported="true"
            />
        <provider
            android:name=".provider.EmailProvider"
            android:authorities="com.bernard.beaconportal.activities.provider.email"
            android:exported="false"
            />

        <receiver
            android:name=".provider.UnreadWidgetProvider"
            android:label="@string/unread_widget_label"
            android:icon="@drawable/icon">
            <intent-filter>
                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
            </intent-filter>
            <meta-data
                android:name="android.appwidget.provider"
                android:resource="@xml/unread_widget_info" />
        </receiver>
        <activity android:name=".activity.UnreadWidgetConfiguration">
            <intent-filter>
                <action android:name="android.appwidget.action.APPWIDGET_CONFIGURE" />
            </intent-filter>
        </activity>
        <activity
            android:name=".activity.UpgradeDatabases"
            android:label="@string/upgrade_databases_title">
        </activity>
        <service
            android:name=".service.DatabaseUpgradeService"
            android:exported="false">
        </service>
       </application>


</manifest>

如果您需要更多代码，或者需要询问有关此代码的问题，请询问。

Answer 1

看起来 K9.app 正在访问单例。这似乎仅在您进行身份验证时设置。您需要更多地了解 K9.app 是如何实例化的。