Java 在Android上读取JSON，没有输出

这是我的JSON数据

{"JSONDATA":[{"key":0,"value":"--Any--"},{"key":61,"value":"Accounting"},{"key":81,"value":"Aerospace & Defense"},{"key":72,"value":"Automotive"},{"key":83,"value":"Banking"},{"key":84,"value":"Biotech"},{"key":85,"value":"Construction"},{"key":86,"value":"Customer Service"},{"key":87,"value":"Education"},{"key":82,"value":"Energy"},{"key":70,"value":"Finance"},{"key":193,"value":"Government"},{"key":194,"value":"Healthcare"},{"key":71,"value":"Insurance"},{"key":73,"value":"Legal"},{"key":62,"value":"Management"},{"key":63,"value":"Manufacturing"},{"key":64,"value":"Marketing\/Advertising"},{"key":77,"value":"Media - Journalism"},{"key":74,"value":"Pharmaceutical"},{"key":75,"value":"Real Estate"},{"key":76,"value":"Research"},{"key":65,"value":"Restaurant"},{"key":66,"value":"Retail"},{"key":67,"value":"Sales"},{"key":78,"value":"Science"},{"key":68,"value":"Telecommunications"},{"key":79,"value":"Training"},{"key":69,"value":"Transportation"},{"key":80,"value":"Utilities"}]}

我想在我的Android应用程序上解码，这是我用过的代码，但我的输出没有任何结果。也没有错误

JSONObject jObject= new JSONObject();
JSONArray menuObject = new JSONArray(jObject.getString("JSONDATA"));
String app;
for (int i = 0; i<menuObject.length(); i++) {
{
 app=menuObject.getJSONObject(i).getString("value").toString();
 a.append(app); // a is my TextView
}

JSONObject jObject=new JSONObject（）；
JSONArray menuObject=新的JSONArray（jObject.getString（“JSONDATA”）；
字符串应用程序；
对于（inti=0；i它是错误的：

JSONArray menuObject = new JSONArray(jObject.getString("JSONDATA"));

尝试：

记住一件事：
使用要解析的JSON字符串创建JSON对象，然后可以从创建的JSON对象获取字符串/JSON对象或JSON数组。
将JSON响应存储在字符串中

String jsonResponse="YOUR JSON RESPONSE STRING";

//按如下方式传递字符串

JSONObject jObject= new JSONObject(jsonResponse);
JSONArray menuObject = jObject.getJSONArray("JSONDATA"));
String app;
for (int i = 0; i<menuObject.length(); i++) {
{
 app=menuObject.getJSONObject(i).getString("value").toString();
 a.append(app); // a is my TextView
}

JSONObject jObject=新的JSONObject（jsonResponse）；
JSONArray menuObject=jObject.getJSONArray（“JSONDATA”）；
字符串应用程序；
对于（int i=0；i使用
JSONObject
和
JSONArray
中的适当getter和setter，您的“JSONDATA”条目不是字符串。请执行以下操作：

JSONObject jObject = new JSONObject(yourJsonString);
JSONArray menuArray = jObject.getJSONArray("JSONDATA");
for (int i = 0; i < menuArray.length(); i++) {
    String app = menuObject.getJSONObject(i).getString("value");
    a.append(app); // a is my TextView
}

JSONObject jObject=新的JSONObject（yourJsonString）；
JSONArray menuArray=jObject.getJSONArray（“JSONDATA”）；
对于（int i=0；i
首先，您没有用任何东西初始化
作业对象

//pass in string
JSONObject jObject= new JSONObject(jsonString);

JSONObject
s需要解析一些东西，否则（按照现在的方式）它们初始化时没有数据，这不是很有帮助

其次，当您真正需要数组时，您正在使用
getString
：

JSONArray menuObject = jObject.getJSONArray("JSONDATA");

getString
用于从JSON对象返回一段字符串数据。
“JSONDATA”
包含一个数组，因此我们需要选择正确的类型进行检索

第三，您有一个冗余的
toString（）
，因为
getString
已经返回了一个
String
：

app=menuObject.getJSONObject(i).getString("value");

使用以下代码解析json字符串

JSONObject obj = new JSONObject(youtString);
JSONArray array = obj.getJSONArray("JSONDATA");
for (int i = 0; i < array.length(); i++) {
  JSONObject c = array.getJSONObject(i);

  String key = c.getString("key");
  String value = c.getString("value");
  a.append(value);
}

JSONObject obj=新的JSONObject（youtString）；
JSONArray数组=obj.getJSONArray（“JSONDATA”）；
对于（int i=0；i
使用以下方法：-

String result="[{"key":0,"value":"--Any--"},{"key":61,"value":"Accounting"},{"key":81,"value":"Aerospace & Defense"},{"key":72,"value":"Automotive"},{"key":83,"value":"Banking"},{"key":84,"value":"Biotech"},{"key":85,"value":"Construction"},{"key":86,"value":"Customer Service"},{"key":87,"value":"Education"},{"key":82,"value":"Energy"},{"key":70,"value":"Finance"},{"key":193,"value":"Government"},{"key":194,"value":"Healthcare"},{"key":71,"value":"Insurance"},{"key":73,"value":"Legal"},{"key":62,"value":"Management"},{"key":63,"value":"Manufacturing"},{"key":64,"value":"Marketing\/Advertising"},{"key":77,"value":"Media - Journalism"},{"key":74,"value":"Pharmaceutical"},{"key":75,"value":"Real Estate"},{"key":76,"value":"Research"},{"key":65,"value":"Restaurant"},{"key":66,"value":"Retail"},{"key":67,"value":"Sales"},{"key":78,"value":"Science"},{"key":68,"value":"Telecommunications"},{"key":79,"value":"Training"},{"key":69,"value":"Transportation"},{"key":80,"value":"Utilities"}]";
JSONArray menuObject = new JSONArray(result);
String app;
for (int i = 0; i<menuObject.length(); i++) {
{
 app=menuObject.getJSONObject(i).getString("value").toString();
 a.append(app); // a is my TextView
}

String result=“[{“key”：0，“value”：”--任意--“}，{“key”：61，“value”：“Accounting”}，{“key”：81，“value”：“Aerospace&defence”}，{“key”：72，“value”：“Automotive”}，{“key”：83，“value”：“Banking”}，{“key”：84，“value”：“Biotech”}，{“key”：85，“value”：“Construction”}，{“key”：86，“value”：“Customer Service”}，{“Customer Service”}，{“key”：87，“value”；“Education”}，{“key”：82，“value”：“Energy”}，{“Energy”：70，“价值”：“金融”}，{“关键”：193，“价值”：“政府”}，{“关键”：194，“价值”：“医疗”}，{“关键”：71，“价值”：“保险”}，{“关键”：73，“价值”：“法律”}，{“关键”：62，“价值”：“管理”}，{“关键”：63，“价值”：“制造”}，{“关键”：64，“价值”：“营销”}，{“关键”：77，“价值”：“媒体-新闻”}，{“关键”：74，“价值”：“制药”}，{“关键”：75，“价值”：“房地产”}，{“关键”：76，“价值”：“研究”}，{“关键”：65，“价值”：“餐厅”}，{“关键”：66，“价值”：“零售”}，{“关键”：67，“价值”：“销售”}，{“关键”：78，“价值”：“科学”}，{“关键”：68，“价值”：“电信”}，{“关键”：79，“价值”：“培训”}，{“关键”：69，“价值”：“交通”}，{“关键”：80，“价值”：“公用事业”}；
JSONArray menuObject=新的JSONArray（结果）；
字符串应用程序；
对于（int i=0；i
String result="[{"key":0,"value":"--Any--"},{"key":61,"value":"Accounting"},{"key":81,"value":"Aerospace & Defense"},{"key":72,"value":"Automotive"},{"key":83,"value":"Banking"},{"key":84,"value":"Biotech"},{"key":85,"value":"Construction"},{"key":86,"value":"Customer Service"},{"key":87,"value":"Education"},{"key":82,"value":"Energy"},{"key":70,"value":"Finance"},{"key":193,"value":"Government"},{"key":194,"value":"Healthcare"},{"key":71,"value":"Insurance"},{"key":73,"value":"Legal"},{"key":62,"value":"Management"},{"key":63,"value":"Manufacturing"},{"key":64,"value":"Marketing\/Advertising"},{"key":77,"value":"Media - Journalism"},{"key":74,"value":"Pharmaceutical"},{"key":75,"value":"Real Estate"},{"key":76,"value":"Research"},{"key":65,"value":"Restaurant"},{"key":66,"value":"Retail"},{"key":67,"value":"Sales"},{"key":78,"value":"Science"},{"key":68,"value":"Telecommunications"},{"key":79,"value":"Training"},{"key":69,"value":"Transportation"},{"key":80,"value":"Utilities"}]";
JSONArray menuObject = new JSONArray(result);
String app;
for (int i = 0; i<menuObject.length(); i++) {
{
 app=menuObject.getJSONObject(i).getString("value").toString();
 a.append(app); // a is my TextView
}