android.database.CursorWindow#putNull ( )源码实例Demo

/**
 * Put the value in given window. If the value type is other than Long,
 * String, byte[] or Double, the NULL will be filled.
 *
 * @return true if succeeded.
 */
private boolean putValue(CursorWindow window, Object value, int pos, int column) {
    if (value == null) {
        return window.putNull(pos, column);
    } else if (value instanceof Long) {
        return window.putLong((Long) value, pos, column);
    } else if (value instanceof String) {
        return window.putString((String) value, pos, column);
    } else if (value instanceof byte[] && ((byte[]) value).length > 0) {
        return window.putBlob((byte[]) value, pos, column);
    } else if (value instanceof Double) {
        return window.putDouble((Double) value, pos, column);
    } else {
        return window.putNull(pos, column);
    }
}
 

/**
 * Put the value in given window. If the value type is other than Long,
 * String, byte[] or Double, the NULL will be filled.
 *
 * @return true if succeeded.
 */
private boolean putValue(CursorWindow window, Object value, int pos, int column) {
    if (value == null) {
        return window.putNull(pos, column);
    } else if (value instanceof Long) {
        return window.putLong((Long) value, pos, column);
    } else if (value instanceof String) {
        return window.putString((String) value, pos, column);
    } else if (value instanceof byte[] && ((byte[]) value).length > 0) {
        return window.putBlob((byte[]) value, pos, column);
    } else if (value instanceof Double) {
        return window.putDouble((Double) value, pos, column);
    } else {
        return window.putNull(pos, column);
    }
}
 

/**
 * Put the value in given window. If the value type is other than Long,
 * String, byte[] or Double, the NULL will be filled.
 *
 * @return true if succeeded.
 */
private boolean putValue(CursorWindow window, Object value, int pos, int column) {
    if (value == null) {
        return window.putNull(pos, column);
    } else if (value instanceof Long) {
        return window.putLong((Long) value, pos, column);
    } else if (value instanceof String) {
        return window.putString((String) value, pos, column);
    } else if (value instanceof byte[] && ((byte[]) value).length > 0) {
        return window.putBlob((byte[]) value, pos, column);
    } else if (value instanceof Double) {
        return window.putDouble((Double) value, pos, column);
    } else {
        return window.putNull(pos, column);
    }
}
 

/**
 * Put the value in given window. If the value type is other than Long,
 * String, byte[] or Double, the NULL will be filled.
 *
 * @return true if succeeded.
 */
private boolean putValue(CursorWindow window, Object value, int pos, int column) {
    if (value == null) {
        return window.putNull(pos, column);
    } else if (value instanceof Long) {
        return window.putLong((Long) value, pos, column);
    } else if (value instanceof String) {
        return window.putString((String) value, pos, column);
    } else if (value instanceof byte[] && ((byte[]) value).length > 0) {
        return window.putBlob((byte[]) value, pos, column);
    } else if (value instanceof Double) {
        return window.putDouble((Double) value, pos, column);
    } else {
        return window.putNull(pos, column);
    }
}
 

/**
 * Put the value in given window. If the value type is other than Long,
 * String, byte[] or Double, the NULL will be filled.
 *
 * @return true if succeeded.
 */
private boolean putValue(CursorWindow window, Object value, int pos, int column) {
    if (value == null) {
        return window.putNull(pos, column);
    } else if (value instanceof Long) {
        return window.putLong((Long) value, pos, column);
    } else if (value instanceof String) {
        return window.putString((String) value, pos, column);
    } else if (value instanceof byte[] && ((byte[]) value).length > 0) {
        return window.putBlob((byte[]) value, pos, column);
    } else if (value instanceof Double) {
        return window.putDouble((Double) value, pos, column);
    } else {
        return window.putNull(pos, column);
    }
}
 

@Override
public void fillWindow(int position, CursorWindow window) {
    if (position < 0 || position > getCount()) {
        return;
    }
    window.acquireReference();
    try {
        moveToPosition(position - 1);
        window.clear();
        window.setStartPosition(position);
        int columnNum = getColumnCount();
        window.setNumColumns(columnNum);
        boolean isFull = false;
        int numRows = 10;

        while (!isFull && --numRows > 0 && moveToNext() && window.allocRow()) {
            for (int i = 0; i < columnNum; i++) {
                String field = getString(i);
                if (field != null) {
                    if (!window.putString(field, getPosition(), i)) {
                        window.freeLastRow();
                        isFull = true;
                        break;
                    }
                } else {
                    if (!window.putNull(getPosition(), i)) {
                        window.freeLastRow();
                        isFull = true;
                        break;
                    }
                }
            }
        }
    } catch (IllegalStateException e) {
        // simply ignore it
    } finally {
        window.releaseReference();
    }
}