java - 查询 ContentProvider 时出现 "Invalid Tables"错误

标签 java android sqlite android-contentprovider

其次，我真的是 android 的新手，还没有完全掌握它的工作方式(对于编写我可以在网上找到的大部分教程的人来说，情况似乎就是这样，所以一个好的快速而肮脏的教程会也很棒)。 继续解决这个问题，我将尝试只发布相关代码，如果我跳过某些内容，请告诉我。

list 条目:

<provider android:name="MyContentProvider" android:authorities="hua.it20910.android.provider"/>

主要 Activity 调用:

Cursor c = getContentProvider().query(MyContentProvider.getTableUri(1), null, null, null, null);

内容提供者:

private static SQLiteDatabase db;
private static final String database_name = "contactlist.db";
private static final int database_version = 1;
private static final String table1="Contacts";
private static final String[] table1_row={"_id","Surname","Name","Phone","Email","Address","Group"};
private static final String table2="Groups";
private static final String[] table2_row={"_id","Name"};

public static final String PROVIDER_NAME = "hua.it20910.android.provider";
public static final Uri CONTACTS_URI = Uri.parse("content://"+ PROVIDER_NAME + "/"+table1);
public static final Uri GROUPS_URI = Uri.parse("Content://"+PROVIDER_NAME + "/"+table2);

private static final int CONTACTS = 1;
private static final int CONTACT_ID = 2;
private static final int GROUPS = 3;
private static final int GROUP_ID = 4;

private static final UriMatcher myMatcher;
static {
    myMatcher = new UriMatcher(UriMatcher.NO_MATCH);
    myMatcher.addURI(PROVIDER_NAME, table1, CONTACTS);
    myMatcher.addURI(PROVIDER_NAME, table1+"/#", CONTACT_ID);
    myMatcher.addURI(PROVIDER_NAME, table2, GROUPS);
    myMatcher.addURI(PROVIDER_NAME, table1+"/#", GROUP_ID);
}
private static final String table1Sql = "CREATE TABLE "
            + table1 + "(" 
            + table1_row[0] + " INTEGER PRIMARY KEY AUTOINCREMENT, " 
            + table1_row[1] + " VARCHAR(25), "
            + table1_row[2] + " VARCHAR(25), " 
            + table1_row[3] + " INTEGER, " 
            + table1_row[4] + " VARCHAR(25), "
            + table1_row[5] + " VARCHAR(25)) ";

    private static final String table2Sql = "CREATE TABLE " 
            + table2 + "("
            + table2_row[0] + " INTEGER PRIMARY KEY AUTOINCREMENT, "
            + table2_row[1] + " VARCHAR(25))";


private class DatabaseHelper extends SQLiteOpenHelper{

    public DatabaseHelper(Context context) {
        super(context, database_name, null, database_version);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL(table1Sql);
        db.execSQL(table2Sql);
    }

    @Override
      public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
         db.execSQL("DROP TABLE IF EXISTS "+table1 );
         db.execSQL("DROP TABLE IF EXISTS "+table2 );
         onCreate(db);
      }     
}


public static Uri getTableUri(int i){
    if (i==1){
        return CONTACTS_URI;
    }
    if (i==2){
        return GROUPS_URI;
    }
    else{
        return null;
    }
}

@Override
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
    SQLiteQueryBuilder sqlBuilder = new SQLiteQueryBuilder();
    switch (myMatcher.match(uri)){
        case CONTACTS:
            sqlBuilder.setTables(table1);
            break;
        case CONTACT_ID:
            sqlBuilder.setTables(table1);
            sqlBuilder.appendWhere("_id=" + uri.getPathSegments().get(1));
            break;
        case GROUPS:
            sqlBuilder.setTables(table2);
            break;
        case GROUP_ID:
            sqlBuilder.setTables(table2);
            sqlBuilder.appendWhere("_id=" + uri.getPathSegments().get(1));
            break;
        default:
            throw new SQLException("Wrong uri " + uri);
    }
    if (sortOrder == null || sortOrder == "")
        sortOrder = "_id DESC";
    Cursor c = db.query(null, projection, selection, selectionArgs, null, null, sortOrder);
    c.setNotificationUri(getContext().getContentResolver(), uri);
    return null;
}

如标题中所述，我目前收到的错误消息是 Invalid tables when executing the query 但我一直在努力解决其他错误才能到达这里，我不确定我是否解决了它们或只是在他们周围走来走去，以便将来再次找到他们，因此非常感谢任何错误纠正。

日志:

01-11 05:43:08.385: E/Trace(930): error opening trace file: No such file or directory (2)
01-11 05:43:08.525: I/ActivityThread(930): Pub hua.it20910.android.provider: hua.it20910.android.MyContentProvider
01-11 05:43:09.515: D/dalvikvm(930): GC_FOR_ALLOC freed 57K, 7% free 2583K/2760K, paused 191ms, total 193ms
01-11 05:43:09.515: I/dalvikvm-heap(930): Grow heap (frag case) to 3.241MB for 635812-byte allocation
01-11 05:43:09.565: D/dalvikvm(930): GC_FOR_ALLOC freed 1K, 6% free 3202K/3384K, paused 43ms, total 43ms
01-11 05:43:09.616: D/dalvikvm(930): GC_CONCURRENT freed <1K, 6% free 3214K/3384K, paused 5ms+13ms, total 52ms
01-11 05:43:09.635: D/AndroidRuntime(930): Shutting down VM
01-11 05:43:09.645: W/dalvikvm(930): threadid=1: thread exiting with uncaught exception (group=0x40a70930)
01-11 05:43:09.655: E/AndroidRuntime(930): FATAL EXCEPTION: main
01-11 05:43:09.655: E/AndroidRuntime(930): java.lang.RuntimeException: Unable to start activity ComponentInfo{hua.it20910.android/hua.it20910.android.MainActivity}: java.lang.IllegalStateException: Invalid tables
01-11 05:43:09.655: E/AndroidRuntime(930):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
01-11 05:43:09.655: E/AndroidRuntime(930):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
01-11 05:43:09.655: E/AndroidRuntime(930):  at android.app.ActivityThread.access$600(ActivityThread.java:141)
01-11 05:43:09.655: E/AndroidRuntime(930):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
01-11 05:43:09.655: E/AndroidRuntime(930):  at android.os.Handler.dispatchMessage(Handler.java:99)
01-11 05:43:09.655: E/AndroidRuntime(930):  at android.os.Looper.loop(Looper.java:137)
01-11 05:43:09.655: E/AndroidRuntime(930):  at android.app.ActivityThread.main(ActivityThread.java:5039)
01-11 05:43:09.655: E/AndroidRuntime(930):  at java.lang.reflect.Method.invokeNative(Native Method)
01-11 05:43:09.655: E/AndroidRuntime(930):  at java.lang.reflect.Method.invoke(Method.java:511)
01-11 05:43:09.655: E/AndroidRuntime(930):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
01-11 05:43:09.655: E/AndroidRuntime(930):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
01-11 05:43:09.655: E/AndroidRuntime(930):  at dalvik.system.NativeStart.main(Native Method)
01-11 05:43:09.655: E/AndroidRuntime(930): Caused by: java.lang.IllegalStateException: Invalid tables
01-11 05:43:09.655: E/AndroidRuntime(930):  at android.database.sqlite.SQLiteDatabase.findEditTable(SQLiteDatabase.java:971)
01-11 05:43:09.655: E/AndroidRuntime(930):  at android.database.sqlite.SQLiteDatabase.queryWithFactory(SQLiteDatabase.java:1161)
01-11 05:43:09.655: E/AndroidRuntime(930):  at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1032)
01-11 05:43:09.655: E/AndroidRuntime(930):  at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1200)
01-11 05:43:09.655: E/AndroidRuntime(930):  at hua.it20910.android.MyContentProvider.query(MyContentProvider.java:178)
01-11 05:43:09.655: E/AndroidRuntime(930):  at android.content.ContentProvider.query(ContentProvider.java:652)
01-11 05:43:09.655: E/AndroidRuntime(930):  at android.content.ContentProvider$Transport.query(ContentProvider.java:189)
01-11 05:43:09.655: E/AndroidRuntime(930):  at android.content.ContentResolver.query(ContentResolver.java:372)
01-11 05:43:09.655: E/AndroidRuntime(930):  at android.content.ContentResolver.query(ContentResolver.java:315)
01-11 05:43:09.655: E/AndroidRuntime(930):  at hua.it20910.android.MainActivity.displayRecords(MainActivity.java:31)
01-11 05:43:09.655: E/AndroidRuntime(930):  at hua.it20910.android.MainActivity.onCreate(MainActivity.java:19)
01-11 05:43:09.655: E/AndroidRuntime(930):  at android.app.Activity.performCreate(Activity.java:5104)
01-11 05:43:09.655: E/AndroidRuntime(930):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
01-11 05:43:09.655: E/AndroidRuntime(930):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
01-11 05:43:09.655: E/AndroidRuntime(930):  ... 11 more

最佳答案

As mentioned in the title the error message I'm currently getting is Invalid tables when executing the query but I've been through a hell of working arround other errors to get here and I'm not sure if I solved them[...]

您得到该异常是正常的，因为您通过了 null作为在 query 中执行 sqlite 查询时的表名ContentProvider 的方法，这一行:

Cursor c = db.query(null, projection, selection, selectionArgs, null, null, sortOrder);

第一个参数 是表名，您必须提供有效的表名才能使查询成功。所以基于Uri您可以选择正确的表并分配一个有效的表名。另外，使用 SQLiteQueryBuilder 的目的是什么？如果您要完全忽略它并直接查询数据库，请使用相同的查询方法？

关于教程，我认为您错过了最重要的一个，the official guide for ContentProviders ，你甚至有在那里构建一个的例子。

关于java - 查询 ContentProvider 时出现 "Invalid Tables"错误，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/14272455/

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