Android：索引1处的绑定值为空错误

Question

我正在开发一个应用程序，我在其中运行后台服务：

startService(new Intent(getApplicationContext(), ContactService.class));

在清单中：

<service android:name=".ContactService" ></service>

而服务代码如下：

public class ContactService extends Service {
    private int mContactCount;
    @Override
    public IBinder onBind(Intent arg0) {
        return null;
    }

    @Override
    public void onCreate() {
        super.onCreate();
        // Get contact count at start of service
        mContactCount = getContactCount();
        this.getContentResolver().registerContentObserver(ContactsContract.CommonDataKinds.Phone.CONTENT_URI, true, mObserver);
        Cursor curval = getApplicationContext().getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null, null, null, null);

        if (curval != null && curval.getCount() > 0) {
            curval.getCount();
        }
        curval.close();
    }

    private int getContactCount() {
        try {
            cursor = getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null, null, null, null);
            if (cursor != null) {
                return cursor.getCount();
            } else {
                cursor.close();
                return 0;
            }
        } catch (Exception ignore) {
        } finally {
            cursor.close();
        }
        return 0;
    }

    private ContentObserver mObserver = new ContentObserver(new Handler()) {
        @Override
        public void onChange(boolean selfChange) {
            new changeInContact().execute();
        }
    };

    public class changeInContact extends AsyncTask<String, Void, String> {
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
        }

        @Override
        protected String doInBackground(String... arg0) {
            ArrayList<Integer> arrayListContactID = new ArrayList<Integer>();
            int currentCount = getContactCount();
            // Add contact
            if (currentCount > mContactCount) {
                // Adding the contact if max contact id from device to sqlite database
            } else if (currentCount < mContactCount) {  
                // Delete contact from sqlite database which is not available in device
            } else if (currentCount == mContactCount) {
                // Check version of contact. If updated change info from device to sqlite
            }

            mContactCount = currentCount;
            return "";
        }

        @Override
        protected void onPostExecute(String result) {
        }
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        return Service.START_STICKY;
    }
}

当我的服务在后台运行时，我收到错误并且我的应用程序崩溃。错误如下：

java.lang.RuntimeException: An error occured while executing doInBackground() at android.os.AsyncTask$3.done(AsyncTask.java:299)
at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
at java.util.concurrent.FutureTask.run(FutureTask.java:137)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
at java.lang.Thread.run(Thread.java:856)
Caused by: java.lang.IllegalArgumentException: the bind value at index 1 is null at android.database.DatabaseUtils.readExceptionFromParcel(DatabaseUtils.java:170)
at android.database.DatabaseUtils.readExceptionFromParcel(DatabaseUtils.java:140)
at android.content.ContentProviderProxy.query(ContentProviderNative.java:366)
at android.content.ContentResolver.query(ContentResolver.java:372)
at android.content.ContentResolver.query(ContentResolver.java:315)
at com.demo.example.ContactService$changeInContact.doInBackground(ContactService.java:577)
at com.demo.example.ContactService$changeInContact.doInBackground(ContactService.java:1)
at android.os.AsyncTask$2.call(AsyncTask.java:287)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
... 5 more
java.lang.IllegalArgumentException: the bind value at index 1 is null at android.database.DatabaseUtils.readExceptionFromParcel(DatabaseUtils.java:170)
at android.database.DatabaseUtils.readExceptionFromParcel(DatabaseUtils.java:140)
at android.content.ContentProviderProxy.query(ContentProviderNative.java:366)
at android.content.ContentResolver.query(ContentResolver.java:372)
at android.content.ContentResolver.query(ContentResolver.java:315)
at com.demo.example.ContactService$changeInContact.doInBackground(ContactService.java:577)
at com.demo.example.ContactService$changeInContact.doInBackground(ContactService.java:1)
at android.os.AsyncTask$2.call(AsyncTask.java:287)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
at java.util.concurrent.FutureTask.run(FutureTask.java:137)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
at java.lang.Thread.run(Thread.java:856)

我不明白出了什么问题。请向我提出您的宝贵建议。由于这个原因，我在我的应用程序中非常糟糕。请给我你的意见。

Answer 1

the bind value 只不过是query 的selectionArgs。如果selectionArgs 在任何时候为空，您将在触发query 时收到此错误。