Question

当我打电话给json并且让它变成“你不能拥有相同的东西时，我想创造一个条件”。当您想要向数据库添加更多数据时，在json值中。

这是我的代码

String nim2, ruang2;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_kelas);
    nim = (EditText) findViewById(R.id.editNim);
    ruang = (EditText) findViewById(R.id.ruangPinjam);

    new daftarMahasiswa().execute();
}

public void nextButton (View view) {
    nim2 = nim.getText().toString();
    ruang2 = ruang.getText().toString();
    if (ruang2.equals(ruangan)) {
        Toast.makeText(KelasActivity.this, "this room has already borrow",Toast.LENGTH_LONG).show();
        ruang.setError("you cannot borrow the room again");
    }else if (nim2.equals(nimMahasiswa)){
        Toast.makeText(KelasActivity.this, "this NIM has borrow the room",Toast.LENGTH_LONG).show();
        nim.setError("you cannot borrow it again");
    }

class daftarMahasiswa extends AsyncTask<String, String, String> {
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pDialog = new ProgressDialog(KelasActivity.this);
        pDialog.setMessage("Loading...");
        pDialog.setIndeterminate(false);
        pDialog.setCancelable(false);
        pDialog.show();
    }

    @Override
    protected String doInBackground(String... params) {
        String link_url = "http://192.168.43.54/datapeminjamankelas/read_mahasiswa.php";
        JSONParser jParser = new JSONParser();
        JSONObject json = null;
        try {
            json = jParser.AmbilJson(link_url);
        } catch (JSONException e) {
            e.printStackTrace();
        }

        try {
            str_json = json.getJSONArray("data");
            for (int i = 0; i < str_json.length(); i++) {
                JSONObject ar = str_json.getJSONObject(i);
                ruangan = ar.getString("ruang").trim();
                nimMahasiswa = ar.getString("nim").trim();
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }

        return null;
    }

    @Override
    protected void onPostExecute(String s) {
        pDialog.dismiss();
    }    
}

这是我的json

 {
  "data": [
    {
      "nim": "103452",
      "ruang": "2702"
    },
    {
      "nim": "102341",
      "ruang": "2504"
    },
    {
      "nim": "103421",
      "ruang": "1101"
    }
  ]
}

我想要做的是＆＃39; nim＆＃39;和＃ruang＆＃39;从json无法再添加相同的值。它诚实地工作，但只有当数据只有1，当它有更多它不再工作。请帮助我做些什么来使它正确

Answer 1

您可以添加＆＃39; nim＆＃39;和＆＃39; ruang＆＃39;单独列表中的值，从那里，您可以检查输入的值是否已经存在。

List<String> nimList = new ArrayList<>();
List<String> ruangList = new ArrayList<>();
for (int i = 0; i < str_json.length(); i++) {
    JSONObject ar = str_json.getJSONObject(i);
    ruangan = ar.getString("ruang").trim();
    nimMahasiswa = ar.getString("nim").trim();
    nimList.add(nimMahasiswa);
    ruangList.add(ruangan);
}

您可以查看如下：

    nim2 = nim.getText().toString();
    ruang2 = ruang.getText().toString();
    if (ruangList.contains(ruang2)) {
           Toast.makeText(KelasActivity.this, "this room has already borrow",Toast.LENGTH_LONG).show();
           ruang.setError("you cannot borrow the room again");
    }else if (nimList.contains(nim2)){
           Toast.makeText(KelasActivity.this, "this NIM has borrow the room",Toast.LENGTH_LONG).show();
           nim.setError("you cannot borrow it again");
    }

Answer 2

最好你可以拥有一个pojo类并覆盖equals方法，如下所示

public class MyData {
  private String myNim;
  private String myRuang;
  //setter & getters here
  @Override
  public boolean equals(Object obj) {
    if(obj instanceOf MyData)
    {
      MyData myData = (MyData) obj;
      return myData.getMyNim().equals(this.myNim)&&myData.getMyRuang().equals(this.myRuang);
    }
    return false;
  }
}

现在您可以使用以下代码检查元素是否存在。

try {
  str_json = json.getJSONArray("data");
  List<MyData> myDataList = new ArrayList<MyData>();
  for (int i = 0; i < str_json.length(); i++) {
    JSONObject ar = str_json.getJSONObject(i);
    ruangan = ar.getString("ruang").trim();
    nimMahasiswa = ar.getString("nim").trim();
    MyData myData = new MyData();
    myData.setMyNim(nimMahasiswa);
    myData.setMyRuang(ruangan);
    if(myDataList.contains(myData))
      //use your logic here to show error 'you cannot have the same thing'
    else
      myDataList.add(myData);
  }
} catch (JSONException e) {
  e.printStackTrace();
}

现在你可以使用具有唯一元素的myDataList。

如何从json创建数据条件

2 个答案: