java.lang.IllegalStateException: Couldn't read row 0, col -1 from CursorWindow.
Make sure the Cursor is initialized correctly before accessing data from it.
SQLiteDatabase 学习过程中，使用query() 查询表单数据时，遇到Couldn't read row 0, col -1 from CursorWindow错误。
排除建表字段错误、拼写错误、query()输入字段错误。当我使用rawQuery()方法取代query()方法，问题就解决了。
代码如下：
1.建表 MyDatabaseHelper
1 private static final String CREATE_CONTACTS = "create table contact (" 2 + "id integer primary key autoincrement, " 3 + "name text, " 4 + "number text )"; 5 6 public MyDatabaseHelper(Context context, String name, CursorFactory factory, int version) { 7 super(context, name, factory, version); 8 } 9 10 @Override 11 public void onCreate(SQLiteDatabase db) { 12 db.execSQL(CREATE_CONTACTS); 13 }
2.查询 根据searchName查询表单
1 private void searchContact(String searchName) { 2 db = dbHelper.getReadableDatabase(); 3 //Cursor cursor = db.query("contact", new String[] {"name"}, "name = ?", new String[] {searchName}, null, null, null); 4 Cursor cursor = db.rawQuery("select * from contact where name = ?", new String[] {searchName}); 5 if(cursor.moveToFirst()) { 6 //String name = cursor.getString(cursor.getColumnIndex("name")); 7 String number = cursor.getString(cursor.getColumnIndex("number")); 8 tv_name.setText(searchName); 9 tv_number.setText(number); 10 tel = "tel:" + number; 11 }else { 12 tv_name.setText("404! Not Found"); 13 tv_number.setText("10086"); 14 tel = "tel:10086"; 15 } 16 cursor.close(); 17 db.close(); 18 }
1.当使用query(String table, String[] columns, String selection, String[] selectionArgs, String groupBy, String having, String orderBy)
String name = cursor.getString(cursor.getColumnIndex("name"))
用这句代码检验 可以获得到name,证明cursor正确指向所要查询数据。
String number = cursor.getString(cursor.getColumnIndex("number"))
但这句代码就会报Couldn't read row 0, col -1 from CursorWindow。
getColumnIndex("number") 返回值竟然是-1，百思不得其解！
2.使用rawQuery(String sql, String[] selectionArgs)
name和number字段都可以准确获得，问题完美解决。