public interface OnErrorListener
    {
        /**
         * Called to indicate an error.
         *
         * @param mp      the MediaPlayer the error pertains to
         * @param what    the type of error that has occurred:
         * <ul>
         * <li>{@link #MEDIA_ERROR_UNKNOWN}
         * <li>{@link #MEDIA_ERROR_SERVER_DIED}
         * </ul>
         * @param extra an extra code, specific to the error. Typically
         * implementation dependent.
         * <ul>
         * <li>{@link #MEDIA_ERROR_IO}
         * <li>{@link #MEDIA_ERROR_MALFORMED}
         * <li>{@link #MEDIA_ERROR_UNSUPPORTED}
         * <li>{@link #MEDIA_ERROR_TIMED_OUT}
         * <li><code>MEDIA_ERROR_SYSTEM (-2147483648)</code> - low-level system error.
         * </ul>
         * @return True if the method handled the error, false if it didn't.
         * Returning false, or not having an OnErrorListener at all, will
         * cause the OnCompletionListener to be called.
         */
        boolean onError(MediaPlayer mp, int what, int extra);
    }

So the problem I have is the error “MEDIA_ERROR_SYSTEM”, the reason is “system version is too low error”… Then I looked it up on the Internet and found that video files are usually in MP4, AVI, etc., but even if they are in the same file format, they may have different encoding formats. For example, common coding formats are: H.264, H.263 and so on. However, many Andorid devices can only support partial encoding, which results in some videos that cannot be played on Andorid devices. If you have to play these videos, it involves the complicated operation of video transcoding… I haven’t learned this skill yet, so I’ll dig a hole and fill it up later