我无法将MySQL查询的结果输出为图表的数据集。我不知道如何将结果传递给一个简单的数组。它在PHP中回应良好并且ajax请求有效，但（我假设）它无法格式化为数组的正确jquery / javascript格式。以下是我的代码的要点：
绘制图表的主页上的JavaScript部分：
<script>
var randomScalingFactor = function(){ return Math.round(Math.random()*100)};
var lineChartData = {
labels : ["January","February","March","April","May","June","July"],
datasets : [
{
label: "Fast Signal",
fillColor : "rgba(220,220,220,0.2)",
strokeColor : "rgba(220,220,220,1)",
pointColor : "rgba(220,220,220,1)",
pointStrokeColor : "#fff",
pointHighlightFill : "#fff",
pointHighlightStroke : "rgba(220,220,220,1)",
data : getFast()
},
{
label: "Slow Signal",
fillColor : "rgba(151,187,205,0.2)",
strokeColor : "rgba(151,187,205,1)",
pointColor : "rgba(151,187,205,1)",
pointStrokeColor : "#fff",
pointHighlightFill : "#fff",
pointHighlightStroke : "rgba(151,187,205,1)",
data : getSlow()
}
]
}
window.onload = function(){
var ctx = document.getElementById("canvas").getContext("2d");
window.myLine = new Chart(ctx).Line(lineChartData, {
responsive: true
});
}
</script>
主页上的AJAX，在图表加载时调用：
<script type="text/javascript">
function test(){
alert("test");
}
function getAll(){
$.ajax({
type:"POST",
url:"dataproc.php",
data:{ action: true,
all: true
},
success:function(data){
$("#dataDiv").html(data);
}
});
}
function getFast(){
$.ajax({
type:"POST",
url:"dataproc.php",
data:{ action: true,
fast: true
},
success:function(data){
$("#fastDiv").html(data);
return data;
}
});
}
function getSlow(){
$.ajax({
type:"POST",
url:"dataproc.php",
data:{ action: true,
slow: true
},
success:function(data){
$("#slowDiv").html(data);
return data;
}
});
}
function getHisto(){
$.ajax({
type:"POST",
url:"dataproc.php",
data:{ action: true,
histo: true
},
success:function(data){
$("#histoDiv").html(data);
return data;
}
});
}
</script>
以及AJAX调用的远程页面：
<?php
if(isset($_POST['action'])){
if(isset($_POST['all'])){
define("DB_DSN", "mysql:host=localhost;dbname=BTCUSD"); //db conn
define("DB_USERNAME","prices"); //db user
define("DB_PASSWORD","********"); // db pass
try {
//echo "Current Price: $".$current;
$con = new PDO(DB_DSN, DB_USERNAME, DB_PASSWORD);
$con->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$sql = "SELECT * FROM 5Minute ORDER BY timestamp ASC";
$stmt = $con->prepare($sql);
$stmt->execute();
$valid = $stmt->fetchAll();
$con = null;
if($valid){
foreach($valid as $res){
$prices[] = (float)$res["price"];
}
$macdArr = trader_macd($prices,12,26,9);
if(end($macdArr[0]) && end($macdArr[1]) && end($macdArr[2])){
echo json_encode($macdArr, JSON_NUMERIC_CHECK);
}
}
}catch(PDOException $e){
echo "Error: ".$e->getMessage();
}
$con = null;
}
if(isset($_POST['fast'])){
define("DB_DSN", "mysql:host=localhost;dbname=BTCUSD"); //db conn
define("DB_USERNAME","prices"); //db user
define("DB_PASSWORD","*******"); // db pass
try {
//echo "Current Price: $".$current;
$con = new PDO(DB_DSN, DB_USERNAME, DB_PASSWORD);
$con->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$sql = "SELECT * FROM 5Minute ORDER BY timestamp ASC";
$stmt = $con->prepare($sql);
$stmt->execute();
$valid = $stmt->fetchAll();
$con = null;
if($valid){
foreach($valid as $res){
$prices[] = (float)$res["price"];
}
$macdArr = trader_macd($prices,12,26,9);
if(end($macdArr[0]) && end($macdArr[1]) && end($macdArr[2])){
$fastArr = array();
foreach($macdArr[0] as $fastVal){
$fastArr[] = $fastVal;
}
echo json_encode($fastArr, JSON_NUMERIC_CHECK);;
}
}
}catch(PDOException $e){
echo "Error: ".$e->getMessage();
}
$con = null;
}
if(isset($_POST['slow'])){
define("DB_DSN", "mysql:host=localhost;dbname=BTCUSD"); //db conn
define("DB_USERNAME","prices"); //db user
define("DB_PASSWORD","********"); // db pass
try {
//echo "Current Price: $".$current;
$con = new PDO(DB_DSN, DB_USERNAME, DB_PASSWORD);
$con->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$sql = "SELECT * FROM 5Minute ORDER BY timestamp ASC";
$stmt = $con->prepare($sql);
$stmt->execute();
$valid = $stmt->fetchAll();
$con = null;
if($valid){
foreach($valid as $res){
$prices[] = (float)$res["price"];
}
$macdArr = trader_macd($prices,12,26,9);
if(end($macdArr[0]) && end($macdArr[1]) && end($macdArr[2])){
$slowArr = array();
foreach($macdArr[1] as $slowVal){
$slowArr[] = $slowVal;
}
echo json_encode($slowArr, JSON_NUMERIC_CHECK);;
}
}
}catch(PDOException $e){
echo "Error: ".$e->getMessage();
}
$con = null;
}
if(isset($_POST['histo'])){
define("DB_DSN", "mysql:host=localhost;dbname=BTCUSD"); //db conn
define("DB_USERNAME","prices"); //db user
define("DB_PASSWORD","*******"); // db pass
try {
//echo "Current Price: $".$current;
$con = new PDO(DB_DSN, DB_USERNAME, DB_PASSWORD);
$con->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$sql = "SELECT * FROM 5Minute ORDER BY timestamp ASC";
$stmt = $con->prepare($sql);
$stmt->execute();
$valid = $stmt->fetchAll();
$con = null;
if($valid){
foreach($valid as $res){
$prices[] = (float)$res["price"];
}
$macdArr = trader_macd($prices,12,26,9);
if(end($macdArr[0]) && end($macdArr[1]) && end($macdArr[2])){
$histoArr = array();
foreach($macdArr[2] as $histoVal){
$histoArr[] = $histoVal;
}
echo json_encode($histoArr, JSON_NUMERIC_CHECK);;
}
}
}catch(PDOException $e){
echo "Error: ".$e->getMessage();
}
$con = null;
}
}
?>
当我将输出作为成功的AJAX查询回显到div时，它显示如下：
[ - 1.066，-0.995，-0.927，-0.863，-0.804，-0.746，-0.739，-0.687]
图表脚本中数据字段的格式正确，但图表不会绘制。
我认为＆＃34;返回数据是错误的;＆＃34;在ajax调用之后将数组结果传递回jquery / javascript的正确方法是什么？
非常感谢任何帮助，谢谢！
答案 0 :(得分：0)
你应该在ajax调用结束后初始化图形。
例如：
var data1;
var data2;
$(document).ready(function() {
//get the first data
.ajax({
type:"POST",
url:"dataproc.php",
data:{ action: true,
slow: true
},
success:function(data){
data1 = data;
getSecondData(); //call to get second data
}
}
});
function getSecondData()
{
.ajax({
type:"POST",
url:"dataproc.php",
data:{ action: true,
histo: true
},
success:function(data){
data2 = data;
drawGraph(); //now draw
}
}
}
function drawGraph()
{
//draw graph with data 1 and data2
}