使用SQL數據庫的錯誤

Question

我正在處理使用SQL數據庫的應用程序的簡單筆記。我編寫了應用程序的一半，當我想通過運行應用程序來測試它時，它崩潰，說不幸的應用程序已停止。不知道問題是什麼？需要幫助

主要activity.java

package com.mycompany.myapp; 

import android.app.*; 
import android.os.*; 
import android.widget.*; 
import android.database.*; 
Import android.content.*; 
Import android.net.*; 
import android.util.*; 

public class MainActivity extends Activity 
{ 
@Override 
protected void onCreate(Bundle savedInstanceState) 
{ 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 

    insertNote("New Note"); 

    Cursor cursor = getContentResolver().query(NotesProvider.CONTENT_URI,DBOpenHelper.ALL_COLUMNS, null, null, null, null); 

    String[] from ={DBOpenHelper.NOTE_TEXT}; 
    int[] to = {android.R.id.text1}; 
    CursorAdapter cursorAdapter = new SimpleCursorAdapter(this, android.R.layout.simple_list_item_1, cursor, from, to,0); 

    ListView noteslist = (ListView) findViewById(android.R.id.list); 
    noteslist.setAdapter(cursorAdapter); 
} 


private void insertNote(String noteText) 
{ 
    ContentValues values = new ContentValues(); 
    values.put(DBOpenHelper.NOTE_TEXT, noteText); 
    Uri noteUri = getContentResolver().insert(NotesProvider.CONTENT_URI, values); 

    Log.d("NOTESACTIVITY", "INSERTED NOTE" + noteUri.getLastPathSegment()); 
} 

}

dbopenhelper.java

package com.mycompany.myapp; 


import android.database.sqlite.*; 
import android.content.*; 

public class DBOpenHelper extends SQLiteOpenHelper 
{ 

//Constants for db name and version 
private static final String DATABASE_NAME = "notes.db"; 
private static final int DATABASE_VERSION = 1; 

//Constants for identifying table and columns 

public static final String TABLE_NOTES = "notes"; 
public static final String NOTE_ID = "_id"; 
public static final String NOTE_TEXT = "noteText"; 
public static final String NOTE_CREATED = "noteCreated"; 

public static final String[] ALL_COLUMNS ={NOTE_ID, NOTE_TEXT, NOTE_CREATED}; 

//SQL to create table 

private static final String TABLE_CREATE = 
"CREATE TABLE " + TABLE_NOTES + " (" + 
NOTE_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + 
NOTE_TEXT + " TEXT, " + 
NOTE_CREATED + " TEXT default CURRENT_TIMESTAMP" + 
")"; 
public DBOpenHelper(Context context){ 
    super(context, DATABASE_NAME, null, DATABASE_VERSION); 
} 

@Override 
public void onCreate(SQLiteDatabase db) 
{ 
    db.execSQL(TABLE_CREATE); 
} 

@Override 
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) 
{ 
    db.execSQL("DROP TABLE IF EXISTS" + TABLE_NOTES); 
    onCreate(db); 
} 

} 

notesprovider？的.java

package com.mycompany.myapp; 


import android.content.*; 
import android.net.*; 
import android.database.*; 
import android.database.sqlite.*; 

public class NotesProvider extends ContentProvider 
{ 

private static final String AUTHORITY = "com.mycompany.myapp.notesprovider"; 
private static final String BASE_PATH = "notes"; 
public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/" + BASE_PATH); 

// Constant to identify the requested operation 
private static final int NOTES = 1; 
private static final int NOTES_ID = 2; 

private static final UriMatcher uriMatcher = new UriMatcher(UriMatcher.NO_MATCH); 


static{ 
    uriMatcher.addURI(AUTHORITY, BASE_PATH, NOTES); 
    uriMatcher.addURI(AUTHORITY,BASE_PATH + "/#", NOTES_ID); 

} 
private SQLiteDatabase database; 

@Override 
public boolean onCreate() 
{ 
    DBOpenHelper helper = new DBOpenHelper(getContext()); 
    database = helper.getWritableDatabase(); 
    return true; 
} 

@Override 
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) 
{ 
    // TODO: Implement this method 
    return database.query(DBOpenHelper.TABLE_NOTES, DBOpenHelper.ALL_COLUMNS, selection, null, null, null, DBOpenHelper.NOTE_CREATED + "DESC"); 
} 

@Override 
public String getType(Uri uri) 
{ 
    // TODO: Implement this method 
    return null; 
} 

@Override 
public Uri insert(Uri uri, ContentValues values) 
{ 
    // TODO: Implement this method 
    long id = database.insert(DBOpenHelper.TABLE_NOTES, null, values); 
    return Uri.parse(BASE_PATH + "/" + id); 
} 

@Override 
public int delete(Uri uri, String selection, String[] selectionArgs) 
{ 
    // TODO: Implement this method 
    return database.delete(DBOpenHelper.TABLE_NOTES, selection, selectionArgs); 
} 

@Override 
public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) 
{ 
    // TODO: Implement this method 
    return database.update(DBOpenHelper.TABLE_NOTES, values, selection, selectionArgs); 
} 

} 

main.xml中

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
android:layout_width="fill_parent" 
android:layout_height="fill_parent" 
android:background="#ffffff"> 

<ListView 
    android:id="@+id/android:list" 
    android:layout_height="match_parent" 
    android:layout_width="match_parent"/> 

機器人的manifest.xml

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

<application 
    android:allowBackup="true" 
    android:icon="@drawable/ic_launcher" 
    android:label="@string/app_name" 
    android:theme="@style/AppTheme" > 
    <activity 
     android:name=".MainActivity" 
     android:label="@string/app_name" > 
     <intent-filter> 
      <action android:name="android.intent.action.MAIN" /> 

      <category android:name="android.intent.category.LAUNCHER" /> 
     </intent-filter> 
    </activity> 
    <provider 
     android:authorities="com.mycompany.myapp.notesprovider" 
     android:name=".NotesProvider" 
     android:exported="false"/> 
</application> 

</manifest> 

logcat的

11-09 11:07:42.904 8351 8351 E     AndroidRuntime at com.android.internal.os ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903) 

11-09 11:07:42.904 8351 8351 E     AndroidRuntime at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698) 

11-09 11:07:42.904 8351 8351 E     AndroidRuntime Caused by: android.database.sqlite.SQLiteException: no such column: noteCreatedDESC (code 1): , while compiling: SELECT _id, noteText, noteCreated FROM notes ORDER BY noteCreatedDESC 

11-09 11:07:42.904 8351 8351 E     AndroidRuntime at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method) 

11-09 11:07:42.904 8351 8351 E     AndroidRuntime at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:889) 

11-09 11:07:42.904 8351 8351 E     AndroidRuntime at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:500) 

11-09 11:07:42.904 8351 8351 E     AndroidRuntime at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588) 

11-09 11:07:42.904 8351 8351 E     AndroidRuntime at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58) 

11-09 11:07:42.904 8351 8351 E     AndroidRuntime at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:37) 

11-09 11:07:42.904 8351 8351 E     AndroidRuntime at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:44) 

11-09 11:07:42.904 8351 8351 E     AndroidRuntime at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1316) 

11-09 11:07:42.904 8351 8351 E     AndroidRuntime at android.database.sqlite.SQLiteDatabase.queryWithFactory(SQLiteDatabase.java:1163) 

11-09 11:07:42.904 8351 8351 E     AndroidRuntime at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1034) 

11-09 11:07:42.904 8351 8351 E     AndroidRuntime at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1202) 

11-09 11:07:42.904 8351 8351 E     AndroidRuntime at com.enlightenme.pac.NotesProvider.query(NotesProvider.java:40) 

11-09 11:07:42.904 8351 8351 E     AndroidRuntime at android.content.ContentProvider.query(ContentProvider.java:966) 

11-09 11:07:42.904 8351 8351 E     AndroidRuntime at android.content.ContentProvider$Transport.query(ContentProvider.java:211) 

11-09 11:07:42.904 8351 8351 E     AndroidRuntime at android.content.ContentResolver.query(ContentResolver.java:478) 

11-09 11:07:42.904 8351 8351 E     AndroidRuntime at com.enlightenme.pac.NotesActivity.onCreate(NotesActivity.java:24) 

11-09 11:07:42.904 8351 8351 E     AndroidRuntime at android.app.Activity.performCreate(Activity.java:5990) 

11-09 11:07:42.904 8351 8351 E     AndroidRuntime at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106) 

11-09 11:07:42.904 8351 8351 E     AndroidRuntime at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278) 

11-09 11:07:42.904 8351 8351 E     AndroidRuntime  ... 10 more 

11-09 11:28:19.561 14991 14991 E   AndroidRuntime FATAL EXCEPTION: main 
11-09 11:28:19.561 14991 14991 E   AndroidRuntime Process: com.enlightenme.pac, PID: 14991 

11-09 11:28:19.561 14991 14991 E   AndroidRuntime java.lang.RuntimeException: Unable to start activity ComponentInfo{com.enlightenme.pac/com.enlightenme.pac.NotesActivity}: android.database.sqlite.SQLiteException: no such column: noteCreatedDESC (code 1): , while compiling: SELECT _id, noteText, noteCreated FROM notes ORDER BY noteCreatedDESC 

11-09 11:28:19.561 14991 14991 E   AndroidRuntime at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325) 

Answer 1

使用noteCreated DESC代替noteCreatedDESC

試試這個：

 @Override 
     public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) 
     { 
     // TODO: Implement this method return 
     database.query(DBOpenHelper.TABLE_NOTES, DBOpenHelper.ALL_COLUMNS, selection, null, null, null, DBOpenHelper.NOTE_CREATED + " DESC"); 
     } 

Answer 2

答案是這裏的logcat：

Caused by: android.database.sqlite.SQLiteException: no such column: noteCreatedDESC (code 1): , while compiling: SELECT _id, noteText, noteCreated FROM notes ORDER BY noteCreatedDESC 

所以你需要在兩者之間添加空格：

noteCreatedDESC 
      ^~~~~!!