Is the documentation for Android Cursor.moveToNext () set correctly?

Question

boolean android.database.Cursor.moveToNext () documentation says:

http://developer.android.com/reference/android/database/Cursor.html#moveToNext%28%29

Move the cursor to the next line.

This method will return false if the cursor has already passed the last record in the result set.

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However, my book says to do the following to extract data from the cursor:

Cursor myCursor = myDatabase.query (...);
if (myCursor.moveToFirst ()) {
    do {
    int value = myCursor.getInt (VALUE_COL);
    // use value
    } while (myCursor.moveToNext ());
}

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? . , , myCursor 1 , . getInt() , moveToNext() true, "" . , , getInt() - undefined.

, :

false, .

PAST ( AT) , moveToNext() false?

Snark ,

Answer 1

Verbatim API:

:      .

---

, , :

→ moveToNext() → → → return false

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, : http://grepcode.com/file/repository.grepcode.com/java/ext/com.google.android/android/2.3.3_r1/android/database/AbstractCursor.java#AbstractCursor.moveToNext%28%29

public final boolean moveToNext() {
  return moveToPosition(mPos + 1);
}

public final boolean moveToPosition(int position) {
    // Make sure position isn't past the end of the cursor
    final int count = getCount();
    if (position >= count) {
        mPos = count;
        return false;
    }

Answer 2

:

Cursor cursor = db.query(...);
while (cursor.moveToNext()) {
    // use cursor
}

, -1, . Cursor.getPosition() docs.

Android Google Code Search. SQLite .

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Answer 3

, , : , sqlite api .

, while for. , , , , , while:

for( boolean haveRow = c.moveToFirst(); haveRow; haveRow = c.moveToNext() ) {
...
}

, , 6 , , , .

Answer 4

, AbstractCursor Android, Jellybean.

unit test, , MatrixCursor:

@Test
public void testCursor() {
  MatrixCursor cursor = new MatrixCursor(new String[] { "id" });
  for (String s : new String[] { "1", "2", "3" }) {
    cursor.addRow(new String[] { s });
  }

  cursor.moveToPosition(0);
  assertThat(cursor.moveToPrevious(), is(true));

  cursor.moveToPosition(cursor.getCount()-1);
  assertThat(cursor.moveToNext(), is(true));

  assertThat(cursor.moveToPosition(c.getCount()), is(true));
  assertThat(cursor.moveToPosition(-1), is(true));
}

, moveToNext, moveToPrevious moveToPosition.

API 16 AbstractCursor.moveToPosition(int position), -, , false , .

, Android, , , , Android, . . / javadoc, . , Cursors/CursorWrappers Android, .

Answer 5

Cursor.moveToNext(), , , . , .

https://issuetracker.google.com/issues/69259484

He recommends the following sentence:
"This method will return false if the current (at run time) record is the last record in the set and there will be no next record."