请帮助我查找错误！我创建了一个内容提供程序，并尝试从数据库读取数据。但我得到
找不到com. example. ifixer. data. ifixerContentProvider的提供程序信息。
1）我在Android ManifestAndroid Manifest.xml中描述了提供程序：

<provider
    android:authorities="package com.example.ifixer.data.IfixerContentProvider"
    android:name=".data.IfixerContentProvider"
    android:enabled="true"
    android:exported="false"
    android:grantUriPermissions="true">
</provider>

2）我在合约中创建了常量IfixerContract.java：

package com.example.ifixer.data;

import android.net.Uri;
import android.provider.BaseColumns;

import java.net.URI;

final public class IfixerContract {

    public static final int DATABASE_VERSION = 1;
    public static final String DATABASE_NAME = "ifixer";

    public static final String SCHEME = "content://";
    public static final String AUTHORITY = "com.example.ifixer.data.IfixerContentProvider";
    public static final String PATH_TASKS = "tasks";

    public static final Uri BASE_CONTENT_URI = Uri.parse(SCHEME+AUTHORITY);

    private IfixerContract(){
    }

    public static final class TaskTable implements BaseColumns{
        public static final String TABLE_NAME = "tasks";

        public static final String KEY_ID = "id";
        public static final String TASK_NAME = "task_name";
        public static final String BEEP_RULE = "beep_rule";
    }
}

1.我的内容提供程序

标识符内容提供程序.java：

public class IfixerContentProvider extends ContentProvider {
    DBHandler dbOpenHelper;

    private static final UriMatcher uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
    private static final int TASKS = 111;
    private static final int TASK_ID = 221;

    static{
        uriMatcher.addURI(IfixerContract.AUTHORITY, IfixerContract.PATH_TASKS, TASKS);
        uriMatcher.addURI(IfixerContract.AUTHORITY, IfixerContract.PATH_TASKS+"/#", TASK_ID);
    }

    @Override
    public boolean onCreate() {
        dbOpenHelper = new DBHandler(getContext());
        return true;
    }

    @Override
    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder){
        SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
        Cursor cursor;

        int match = uriMatcher.match(uri);
        switch(match){
            case TASKS:{
                Log.d("db_task", "I'm in TASKS");
                cursor = db.query(TaskTable.TASK_NAME,
                        projection, selection, selectionArgs,
                        null, null, sortOrder);
                break;
            }
            case TASK_ID:{
                Log.d("db_task", "I'm in TASK_ID");
                selection = TaskTable.KEY_ID+"=?";
                selectionArgs = new String[]{String.valueOf(ContentUris.parseId(uri))};
                cursor = db.query(TaskTable.TABLE_NAME,
                        projection, selection, selectionArgs,
                        null, null, sortOrder);
                break;
            }
            default:{
                Log.d("db_task", "Incorrect URI");
                throw new IllegalArgumentException("Can't query incorrect URI "+uri);
            }
        }
        return cursor;
    }

    @Override
    public Uri insert(Uri uri, ContentValues contentValues) {
        SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
        Cursor cursor;

        int match = uriMatcher.match(uri);
        switch(match){
            case TASKS:{
                    long id = db.insert(TaskTable.TABLE_NAME,
                            null,
                            contentValues);
                    if(id == -1) {
                        Log.d("db_uri", "Insertion failed for " + uri);
                        return null;
                    }
                    return ContentUris.withAppendedId(uri, id);
            }
            default:{
                Log.d("db_uri", "Insertion failed for");
                return null;
            }
        }
    }

    @Override
    public int delete(Uri uri, String s, String[] strings) {
        return 0;
    }

    @Override
    public int update(Uri uri, ContentValues contentValues, String s, String[] strings) {
        return 0;
    }

    @Override
    public String getType(Uri uri) {
        return null;
    }
}

1.还有一个Main Activity的片段，我尝试在其中读取数据：主要活动.java：

@Override
protected void onStart() {
    super.onStart();
    displayTasks();
}

private void displayTasks(){
    String[] projection = {
            TaskTable.KEY_ID,
            TaskTable.TASK_NAME,
            TaskTable.BEEP_RULE
    };

    Cursor cursor = getContentResolver().query(
            Uri.parse("content://com.example.ifixer.data.IfixerContentProvider/tasks"), //IfixerContract.TASK_CONTENT_URI,
            projection,
            null,
            null,
            null
    );
    if(cursor == null){
        Log.d("db_task", "Get nothing");
    }
    dataTextView.setText("Все задачи \n\n");
    dataTextView.append(TaskTable.KEY_ID
            +" "+TaskTable.TASK_NAME
            +" "+TaskTable.BEEP_RULE);

    int idIndex = cursor.getColumnIndex(TaskTable.KEY_ID);
    int idTaskName = cursor.getColumnIndex(TaskTable.TASK_NAME);
    int idBeepRule = cursor.getColumnIndex(TaskTable.BEEP_RULE);

    while(cursor.moveToNext()){
        int currentId = cursor.getInt(idIndex);
        String currentTaskName = cursor.getString(idTaskName);
        String currentRule = cursor.getString(idBeepRule);

        dataTextView.append("\n"+String.valueOf(currentId)+" "+currentTaskName+" "+currentRule);
    }
    cursor.close();
}

拜托，让我明白我做错了什么？