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lounah's questions

Martin Hope
lounah
Asked: 2020-07-14 22:25:19 +0000 UTC
  • 0

你好。有一个简单的 html 表单。单击“提交”按钮时，我想在此表单中添加另一个“聊天自我”元素。我怎样才能做到这一点？我刚开始研究这个。如果有任何链接，我将不胜感激。

<!DOCTYPE html>
<html>
<head>
	<title>ПростоЧат</title>
	<link rel="stylesheet" type="text/css" href="style.css">
	<meta charset="utf-8">
</head>

<body>

	<div class="chatWindow">
		<div class="chatLog">
		
			<div class="chat friend">
				<p class="message-time">11:42</p>
				<p class="name">#1</p>
				<p class="chat-message">Сообщение #1</p>
			</div>
			
			<div class="chat self">
				<p class="message-time">11:43</p>
				<p class="name">#2</p>
				<p class="chat-message">Сообщение #2</p>
			</div>
			
			<div class="chat friend">
				<p class="message-time">11:45</p>
				<p class="name">#1</p>
				<p class="chat-message">Сообщение #3</p>
			</div>
			
			<div class="chat self">
				<p class="message-time">11:47</p>
				<p class="name">#2</p>
				<p class="chat-message">Сообщение #4</p>
			</div>
			

		</div>
		
		<div class="chat-form">
			<textarea></textarea>
			<button>Отправить</button>
		</div>
		
	</div>

</body>

</html>

javascript
Martin Hope
lounah
Asked: 2020-01-07 19:02:23 +0000 UTC
  • 0

你好

我有看起来像这样的 JSON：

{
"response": {
"count": 10,
"items": [{...}, {...}, {...}, {...}]
}
}

items数组的每个元素包含或不包含copy_history数组。 通常，items 数组如下所示：

"items": [{
"id": 111,
"from_id": -119473366,
"owner_id": -119473366,
"date": 1483779506,
"marked_as_ads": 0,
"post_type": "post",
"text": "",
"copy_history": [{
"id": 30679,
"owner_id": -96126130,
"from_id": -96126130,
"date": 1483772560,
"post_type": "post",
"text": "",
"attachments": [{
"type": "photo",
"photo": {
"id": 456240780,
"album_id": -7,
"owner_id": -96126130,
"user_id": 100,
"photo_75": "https://pp.vk.me/...a3e/0zDlnwXV97M.jpg",
"photo_130": "https://pp.vk.me/...a3f/is7lDvyh3JE.jpg",
"photo_604": "https://pp.vk.me/...a40/Z6vXcOY-cf4.jpg",
"photo_807": "https://pp.vk.me/...a41/g9QedfvZoZg.jpg",
"width": 640,
"height": 521,
"text": "",
"date": 1483140936,
"post_id": 29964,
"access_key": ""
}
}]

有必要遍历每个 items 元素，从中获取 id 字段的值，并找出它是否包含copy_history数组。

请帮帮我。提前致谢

php
Martin Hope
lounah
Asked: 2020-10-23 17:44:18 +0000 UTC
  • 0

你好。有一个聊天活动，其中包含ListView消息。对于ListViewitem'a，有两种样式：左侧的消息（来自对话者），右侧的消息（您的）。

有一段代码，在给定的 URI 处，从服务器接收 JSON，它被解析为消息，然后解析为ListView项目。

JSON 看起来像这样：author:"author",reciever:"reciever",time:"time",content:"content"

所以，我需要根据谁拥有消息，它在ListView. 那些。如果我们收到消息，则ListViewitem'a 的样式在左侧，如果我们发送消息，则在右侧。（与所有使者一样）。

private class ListViewLoaderTask extends AsyncTask<String, Void, SimpleAdapter> {

    JSONObject jObject;

    @Override
    protected SimpleAdapter doInBackground(String... strJson) {
        try {
            jObject = new JSONObject(strJson[0]);
            parse(jObject);
        } catch (Exception e) {
            Log.d("JSON Exception1", e.toString());
        }


        List<HashMap<String, Object>> messages = null;

        try {
            messages = parse(jObject);
        } catch (Exception e) {
            Log.d("Exception", e.toString());
        }

        String[] from = {"content", "time", "author"};
        int[] to = {R.id.contentMSG, R.id.timeMSG, R.id.usernameMSG};

        /*
            Вот здесь нужно исходя из того, кто автор сообщения,
            выбрать layout

         */
        SimpleAdapter adapter = new SimpleAdapter(getBaseContext(), messages, R.layout.one_msg_item, from, to);
        adapter.notifyDataSetChanged();

        return adapter;
    }


}


public List<HashMap<String, Object>> parse(JSONObject jObject) {

    JSONArray jMessages = null;
    try {
        jMessages = jObject.getJSONArray("Messages");
    } catch (JSONException | NullPointerException e) {
        e.printStackTrace();
    }

    return getMessages(jMessages);
}

private List<HashMap<String, Object>> getMessages(JSONArray jMessages) {
    List<HashMap<String, Object>> messagesList = new ArrayList<HashMap<String, Object>>();
    HashMap<String, Object> message = null;

    for (int i = 0; i < jMessages.length(); i++) {
        try {
            message = getMessage((JSONObject) jMessages.get(i));
            messagesList.add(message);

        } catch (JSONException | NullPointerException e) {
            e.printStackTrace();
        }
    }
    return messagesList;
}


private HashMap<String, Object> getMessage(JSONObject jMessage) {
    HashMap<String, Object> message = new HashMap<String, Object>();
    String author = "";
    String client = "";
    String time = "";
    String content = "";
    try {
        author = jMessage.getString("author");
        client = jMessage.getString("client");
        time = jMessage.getString("time");
        content = jMessage.getString("content");

        message.put("author", author);
        message.put("client", client);
        message.put("time", time);
        message.put("content", content);

    } catch (JSONException e) {
        e.printStackTrace();
    }
    return message;
}
android
Martin Hope
lounah
Asked: 2020-09-07 03:11:50 +0000 UTC
  • 2

你好。需要实现矩阵乘法，代码如下：

public class MatrixMultiplier {

    private  int[][] transportMatrix(int[][] a) {
        int[][] b = new int[a.length][a.length];
        for (int i = 0; i < a.length; ++i)
            for (int j = 0; j < a.length; ++j) {
                b[i][j] = a[j][i];
            }
        return b;
    }

    public int[][] multiply(int[][] mA, int[][] mB) {
        int mSize = mA.length;
        mB = transportMatrix(mB);
        int nSize = mB[0].length;
        int o = mB.length;
        int[][] mResult = new int[mSize][nSize];

        for (int i = 0; i < mSize; i++) {
            for (int j = 0; j < nSize; j++) {
                for (int k = 0; k < o; k++) {
                    System.out.print(i + " " + j);
                    mResult[i][j] += mA[i][k] * mB[k][j];
                }
            }
        }

        for (int i = 0; i < mResult.length; i++) {
            for (int j = 0; j < mResult[0].length; j++) {
                System.out.format("%6d ", mResult[i][j]);
            }
            System.out.println();
        }

        return mResult;
    }
}

public class MatrixMultiply {

    private static int[][] mA;
    private static int[][] mB;
    private static int[][] mResult;

    public static void main(String[] args) {
        MatrixMultiplier matrixMultiplier = new MatrixMultiplier();
         mA = new int[][] {{5,3,2},
                          {3,1,0},
                          {1,4,1},
                          {8,2,1}};

         mB = new int[][] {{5,6,2},
                          {3,1,0},
                          {1,4,1},
                          {8,2,1},
                          {3,1,1}};

        mResult = new int[mA.length][mB[0].length];
        mResult = matrixMultiplier.multiply(mA, mB);
    }

}

结果异常：

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 3
at matrix.MatrixMultiplier.transportMatrix(MatrixMultiplier.java:8)
at matrix.MatrixMultiplier.multiply(MatrixMultiplier.java:15)
at matrix.MatrixMultiply.main(MatrixMultiply.java:23)

为什么？

java
Martin Hope
lounah
Asked: 2020-08-23 15:28:23 +0000 UTC
  • 3

我有一个messages看起来像这样的表：_id (prim key), author, client, time, content.

让它具有以下值：

 _id | author | client | time  | content
--------------------------------------
   1 |  user  |  you   | 21:52 | hi   
   2 |  user  |  you   | 20:43 | wassup   
   3 |  user2 |  you   | 17:45 | привет   
   4 |  user2 |  you   | 18:20 | :(

从这个表中，您需要从每个作者那里得到一条（最后一条）消息，其中client = you.

那些。查询应返回 ID 为 1 和 4（hi和:(）的消息。我怎样才能做到这一点？

mysql
Martin Hope
lounah
Asked: 2020-08-22 02:43:00 +0000 UTC
  • 2

你好。MySQL 中有一张表，用于存储用户消息。(_id, from_id, to_id, 日期, 内容 ) 来自所有通信的所有消息都将存储在该表中。我明白这是完全不合理和错误的，因为从服务器下载信件是通过一个简单的 SELECT by from_id 并按日期排序来实现的。那么，如何合理地建表存储用户对应关系，使得数据库查询不至于消息量过大而过长呢？

mysql
Martin Hope
lounah
Asked: 2020-07-30 00:49:49 +0000 UTC
  • 1

你好。我正在为 Android 上一个非常简单的客户端-服务器应用程序编写用户授权测试模型。实现如下：用户在设备上输入登录名和密码 -> 它们被发送到服务器，在服务器上使用 mysql select'a 搜索登录名和密码。如果mysql_num_rows() = 0（没有用户使用这样的登录名和密码），我调用http_response_code(401)方法。 该响应代码由应用程序使用connection.getResponseCode()方法接收

所以，问题是：每次，无论登录名和密码是否正确，connection.getResponseCode() 都会返回 200。

可能是什么问题或我做错了什么？这是代码（提前对它的糟糕表示歉意）

<?php

$mysql_host = "localhost";
$mysql_user = "db";
$mysql_password = "db";
$mysql_database = "db";

mysql_connect($mysql_host, $mysql_user, $mysql_password);
mysql_select_db($mysql_database);
mysql_set_charset('utf8');

if (isset($_GET["action"])) {
    $action = $_GET['action'];
}

if (isset($_GET["username"])) {
    $username = $_GET['username'];
}

if (isset($_GET["password"])) {
    $password = $_GET['password'];
}

if ($action == authentication) {
    $query = "SELECT username, password FROM users WHERE username='$username' AND password='$password'";
    $result = mysql_query($query);
    $rows = mysql_num_rows($result);
    if ($rows = 0) {
        http_response_code(401);
        exit;
    }
}

?>
php