Question

我正在尝试使用PHP文件从Android（Xampp）数据库获取数据。我在String变量中获得了所需的数据，但似乎我的方法没有进入for循环。以下是我的代码。

@SuppressLint("NewApi")
protected void onPostExecute(String result){         
    //parse json data    
    try {
        System.out.println("in jsn try");
        String s = "";
        System.out.println("after jsn string s");
        JSONArray jArray = new JSONArray(result);
        System.out.println("after creating json array "+result);// it executes fine and prints all records
        System.out.println("jarray lenght is "+jArray.length());// it execute fine and prints the length 3 which is fine
        for (int i = 0; i < jArray.length(); i++) {      // problem here 
            System.out.print("in jsn loop");
            JSONObject json = jArray.getJSONObject(i);
            System.out.print("json object");
            s = s +"Name : "+json.getString("Name")+" "+json.getString("Email");  
        }
        System.out.print("Success in json" +s);
        //  resultView.setText(s);   
    } 
    catch (Exception e) {
        Log.e("log_tag", "Error Parsing Data "+e.toString()); 
    }    
}

响应变量打印3条记录

[
    {
        "PId":"1111",
        "Name":"Rukhsar",
        "Email":"rukhsar_arshad93@yahoo.com",
        "Address":"Rawalpindi"
    },
    {
        "PId":"2222",
        "Name":"Sidra",
        "Email":"sidra_arshad@yahoo.com",
        "Address":"Rawalpindi"
    }, 
    {
        "PId":"3333",
        "Name":"Sehrish ",
        "Email":"sehrishali686@yahoo.com",
        "Address":"Islamabad"
    }
]

Answer 1

这可以解决您的问题

public class User {
    private String Pid;
    private String name;
    private String email;
    private String address;

    //implement getter setters
    //implement to string method
}

public void parseJSON(String result) {          
    try {   
        JSONArray jArray = new JSONArray(result);
        List<User> usersList = new ArrayList<User>();
        for (int i = 0; i < jArray.length(); i++) {      // problem here 
            User user = new User();
            JSONObject json = jArray.getJSONObject(i);
            user.setPid(json.getString("PId"));
            user.setName(json.getString("Name"));
            user.setEmail(json.getString("Email"));
            user.setAddress(json.getString("Address"));

            Log.i("User data is : ",User.toString);
            usersList.add(user);
        }
    } 
    catch (Exception e) {
        Log.e("log_tag", "Error Parsing Data "+e.toString());
    }
}

Answer 2

@SuppressLint("NewApi")
protected void onPostExecute(String result){         
    //parse json data    
    try {
        System.out.println("in jsn try");
        String s = "";
        System.out.println("after jsn string s");
        JSONArray jArray = new JSONArray(result);
        System.out.println("after creating json array "+result);// it executes fine and prints all records
        System.out.println("jarray lenght is "+jArray.length());// it execute fine and prints the length 3 which is fine
        for (int i = 0; i < jArray.length(); i++) {      // problem here 
            System.out.print("in jsn loop");
            JSONObject json = jArray.getJSONObject(i);
            System.out.print("json object");
            s = s +"Name : "+json.getString("Name")+" "+json.getString("Email");  
        }
        System.out.print("Success in json" +s);
        //  resultView.setText(s);   
    } 
    catch (Exception e) {
        Log.e("log_tag", "Error Parsing Data "+e.toString()); 
    }    
}

我看到这段代码存在一些问题。首先，您使用System.out.print代替System.out.println。更好的是，因为您正在使用Android，所以使用Log.w(String, String)。还

s = s +"Name : "+json.getString("Name")+" "+json.getString("Email");

你应该附加换行符：

String line = "Name : "+json.getString("Name")+" "+json.getString("Email");
s += line + "\n"; //so it starts on a newline
Log.d("json", line); //while you're at it, Log that line!

<强>加成：

你应该使用调试器！在for循环中添加断点，并在调试模式下运行！ Eclipse中的标准功能也适用于Android。

修改

所以我对你的代码的看法是：

private static final String NAME = "Name"; private static final String EMAIL = "Email"; @SuppressLint("NewApi") protected void onPostExecute(String result) { try { JSONArray array = new JSONArray(result); for (int i = 0; i < array.length(); i++) { JSONObject user = array.getJSONObject(i); resultView.append("Name : " + user.getString(NAME) + " - " + user.getString(EMAIL) + "\n"); } } catch (JSONException jse) { Log.wtf("error", "cant parse json"); //yeah, Log.wtf actually exists :) } }

JSON循环android无法正常工作

2 个答案: