我目前正忙于 Unity 的一个项目。对于这个项目，我需要使用和处理 json 数据。
这是json文件：
{
"exerciseFrame": {
"currentFrameRate": 115.003,
"gestures": [],
"hands": [
{
"direction": [
-0.21788,
0.396045,
-0.892007
],
"id": 67,
"palmNormal": [
-0.207517,
-0.911865,
-0.354174
],
"palmPosition": [
76.5549,
114.137,
5.89759
],
"palmVelocity": [
11.5489,
-12.4382,
30.413
],
"r": [
[
0.985174,
0.0992006,
-0.139971
],
[
-0.110688,
0.990883,
-0.0768105
],
[
0.131075,
0.0911648,
0.987172
]
],
"s": 0.877737,
"sphereCenter": [
53.6198,
53.1508,
-39.351
],
"sphereRadius": 91.0197,
"stabilizedPalmPosition": [
74.1678,
112.23,
3.77527
],
"t": [
-20.2956,
10.8737,
19.0197
],
"timeVisible": 3.23297
}
],
"id": 470433,
"interactionBox": {
"center": [
0,
189,
0
],
"size": [
209.24,
209.24,
146.232
]
},
"pointables": [
{
"direction": [
-0.204191,
-0.171441,
-0.963802
],
"handId": 67,
"id": 83,
"length": 79.2433,
"stabilizedTipPosition": [
54.4213,
125.134,
-95.3633
],
"timeVisible": 1.79999,
"tipPosition": [
58.1631,
128.283,
-96.3226
],
"tipVelocity": [
11.7388,
-0.426162,
2.39705
],
"tool": false,
"touchDistance": 0.16562,
"touchZone": "hovering"
},
{
"direction": [
-0.128641,
0.0244301,
-0.99139
],
"handId": 67,
"id": 25,
"length": 73.593,
"stabilizedTipPosition": [
84.4969,
125.889,
-91.8182
],
"timeVisible": 1.40869,
"tipPosition": [
88.0132,
128.67,
-92.9798
],
"tipVelocity": [
9.78409,
-4.46077,
-10.2516
],
"tool": false,
"touchDistance": 0.0726596,
"touchZone": "hovering"
},
{
"direction": [
-0.231257,
-0.0952694,
-0.968217
],
"handId": 67,
"id": 62,
"length": 65.8749,
"stabilizedTipPosition": [
27.6915,
127.768,
-78.6761
],
"timeVisible": 0.913038,
"tipPosition": [
30.0744,
130.094,
-78.9935
],
"tipVelocity": [
11.5967,
-2.61466,
-3.92538
],
"tool": false,
"touchDistance": 0.123818,
"touchZone": "hovering"
},
{
"direction": [
-0.0484869,
0.109018,
-0.992857
],
"handId": 67,
"id": 73,
"length": 46.8336,
"stabilizedTipPosition": [
115.627,
114.182,
-61.4815
],
"timeVisible": 0.739126,
"tipPosition": [
118.889,
116.921,
-62.7602
],
"tipVelocity": [
2.0058,
-14.1922,
26.0571
],
"tool": false,
"touchDistance": 0.308196,
"touchZone": "hovering"
},
{
"direction": [
-0.757118,
0.0997547,
-0.645617
],
"handId": 67,
"id": 37,
"length": 47.2933,
"stabilizedTipPosition": [
-13.0828,
113.28,
3.91602
],
"timeVisible": 0.913038,
"tipPosition": [
-10.3237,
117.652,
2.30821
],
"tipVelocity": [
9.14501,
5.11948,
-3.45668
],
"tool": false,
"touchDistance": 0.0164196,
"touchZone": "hovering"
}
],
"r": [
[
0.564536,
0.157925,
-0.81016
],
[
0.200296,
-0.978399,
-0.0511501
],
[
-0.800738,
-0.133395,
-0.583973
]
],
"s": -443.531,
"t": [
22821.5,
-11650.1,
-3347.64
],
"timestamp": 5463086706
}
}
我已使用以下脚本将其加载到统一中（根据本教程http://www.paultondeur.com/2010/03/23/tutorial-loading-and-parsing-external-xml-and-json-files-with- unity-part-2-json/ )
using UnityEngine;
using LitJson;
using System;
using System.Collections;
public class LoadJSON : MonoBehaviour
{
IEnumerator Start()
{
//Load JSON data from a URL
string url = "http://localhost/project/application/exercise.json";
WWW www = new WWW(url);
//Load the data and yield (wait) till it's ready before we continue executing the rest of this method.
yield return www;
if (www.error == null)
{
//Process exercises found in JSON file
ProcessExercises(www.data);
}
else
{
Debug.Log("ERROR: " + www.error);
}
}
private void ProcessExercises(string jsonString)
{
Debug.Log (jsonString);
JsonData jsonExercise = JsonMapper.ToObject(jsonString); // convert json data to object.
Exercise exercise;
for(int i = 0; i<jsonExercise["exerciseFrame"].Count; i++) // for each exerciseFrame data in the .json file
{
Debug.Log(jsonExercise["exerciseFrame"].Count);
}
}
private void loadExercise(){
}
}`
它按计划进行，直到应该将 json 数据转换为对象的行：
JsonData jsonExercise = JsonMapper.ToObject(jsonString); // convert json data to object.
我收到以下错误，我不知道出了什么问题。因为 jsonString 是一个带数据的字符串。
`ArgumentNullException: Argument cannot be null.
Parameter name: key
System.Collections.Generic.Dictionary`2[System.String,LitJson.PropertyMetadata].ContainsKey (System.String key) (at /Applications/buildAgent/work/c514da0c8183631c/mcs/class/corlib/System.Collections.Generic/Dictionary.cs:458)
LitJson.JsonMapper.ReadValue (System.Type inst_type, LitJson.JsonReader reader)
LitJson.JsonMapper.ReadValue (System.Type inst_type, LitJson.JsonReader reader)
LitJson.JsonMapper.ReadValue (System.Type inst_type, LitJson.JsonReader reader)
LitJson.JsonMapper.ReadValue (System.Type inst_type, LitJson.JsonReader reader)
LitJson.JsonMapper.ToObject[JsonData] (System.String json)
LoadJSON.ProcessExercises (System.String jsonString) (at Assets/Scripts/JSON/LoadJSON.cs:32)
LoadJSON+<Start>c__Iterator1.MoveNext () (at Assets/Scripts/JSON/LoadJSON.cs:20)`
我真的希望这里有人可以帮助我。非常感谢您的时间！