如何将 PLEASE SELECT 错误添加到 JSON Spinner

Question

我有一个可以上传图片到我公司服务器的应用我有 2 个微调器填充了 json 数据，微调器中的 selected 项目被传递给一个 uri.builder 用于上传 url，我在 SO 上看到很多关于在微调器上设置请 select 选项的问题，但是我的微调器的请 select 选项被编码到我的 JSON 数据中作为一个项目。现在我想要的是，如果 select 项目被 selected 以提示用户 select 微调器中的项目

，应用程序将给出错误

总而言之，我的微调器中填充了 json 数据，json 数据中的第一项是 "Please select" 现在我希望出现一条错误消息，如果请 select 选项被选中。

   public class SecondActivity extends AppCompatActivity implements 
  View.OnClickListener {
private final int PICK_IMAGE=12345;
private final int REQUEST_CAMERA=6352;
private static final int REQUEST_CAMERA_ACCESS_PERMISSION=5674;
private Bitmap bitmap;
private ImageView imageView;

String myURL;
Spinner spinner;
Spinner spinner2;
String URL;
String URL2;
ArrayList<String> CategoryName;
ArrayList<String> ClientName;
String Item;
String Item2;
String email;
String clientId;
String pwd;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_second);
    imageView=findViewById(R.id.imageView);
    Button fromCamera=findViewById(R.id.fromCamera);
    Button fromGallery=findViewById(R.id.fromGallery);
    Button upload=findViewById(R.id.upload);
    CategoryName=new ArrayList<>();
    ClientName=new ArrayList<>();
    spinner=findViewById(R.id.spinner);
    spinner2=findViewById(R.id.spinner2);
    email = getSharedPreferences("MyPrefs", MODE_PRIVATE).getString("name", "");
    clientId= getSharedPreferences("MyPrefs", MODE_PRIVATE).getString("id", "");
    pwd= getSharedPreferences("MyPrefs", MODE_PRIVATE).getString("password", "");
    CheckBox chk =findViewById(R.id.chk1);


    if (chk.isChecked()) {
        Uri.Builder builder=new Uri.Builder();
        builder.scheme("https")
                .authority("www.smartpractice.co.za")
                .appendPath("files-upload-phone-app.asp")
                .appendQueryParameter("MyForm", "Yes")
                .appendQueryParameter("ClientID", clientId)
                .appendQueryParameter("Username", email)
                .appendQueryParameter("Pwd", pwd)
                .appendQueryParameter("Category", Item)
                .appendQueryParameter("ClientName", Item2)
                .appendQueryParameter("NoEmail", "Yes");
        myURL=builder.build().toString();
    } else {
        Uri.Builder builder=new Uri.Builder();
        builder.scheme("https")
                .authority("www.smartpractice.co.za")
                .appendPath("files-upload-phone-app.asp")
                .appendQueryParameter("MyForm", "Yes")
                .appendQueryParameter("ClientID", clientId)
                .appendQueryParameter("Username", email)
                .appendQueryParameter("Pwd", pwd)
                .appendQueryParameter("Category", Item)
                .appendQueryParameter("ClientName", Item2)
                .appendQueryParameter("NoEmail", "Yes");

        myURL=builder.build().toString();
    }


    upload.setOnClickListener(this);
    fromCamera.setOnClickListener(this);
    fromGallery.setOnClickListener(this);
    Uri.Builder builder=new Uri.Builder();
    builder.scheme("https")
            .authority("www.smartpractice.co.za")
            .appendPath("app-categories.asp")
            .appendQueryParameter("MyForm", "Yes")
            .appendQueryParameter("ClientID",clientId )
            .appendQueryParameter("Username",email )
            .appendQueryParameter("Pwd",pwd );
    URL=builder.build().toString();

    Uri.Builder builder2=new Uri.Builder();
    builder2.scheme("https")
            .authority("www.smartpractice.co.za")
            .appendPath("app-clients.asp")
            .appendQueryParameter("MyForm", "Yes")
            .appendQueryParameter("ClientID",clientId )
            .appendQueryParameter("Username",email )
            .appendQueryParameter("Pwd",pwd );
    URL2=builder2.build().toString();
    loadSpinnerData(URL);
    loadSpinnerData2(URL2);

项目 select离子代码

上的微调器 1

   spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener()
    {
        @Override
        public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {

            String country=spinner.getItemAtPosition(spinner.getSelectedItemPosition()).toString();
            Toast.makeText(getApplicationContext(), country, Toast.LENGTH_LONG).show();
            Item=spinner.getSelectedItem().toString();
            spinner.getSelectedItemPosition();





        }

        @Override
        public void onNothingSelected(AdapterView<?> adapterView) {


        }
    });

旋转器 2 on itme select离子代码

spinner2.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
    @Override
    public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
        String country=spinner2.getItemAtPosition(spinner2.getSelectedItemPosition()).toString();
        Toast.makeText(getApplicationContext(), country, Toast.LENGTH_LONG).show();
        Item2=spinner2.getSelectedItem().toString();



    }

    @Override
    public void onNothingSelected(AdapterView<?> adapterView) {


    }




}

}

微调器 1 从服务器加载 JSON 数据的代码

   private void loadSpinnerData(String url) {

        RequestQueue requestQueue=Volley.newRequestQueue(getApplicationContext());
        StringRequest stringRequest=new StringRequest(Request.Method.GET, url, new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {



                try {
                    JSONObject jsonObject=new JSONObject(response);

                    if (jsonObject.getInt("success") == 1) {

                        JSONArray jsonArray=jsonObject.getJSONArray("Name");
                        for (int i=0; i < jsonArray.length(); i++) {
                            JSONObject jsonObject1=jsonArray.getJSONObject(i);

                            String country=jsonObject1.getString("Category");
                            CategoryName.add(country);
                        }
                    }
                    spinner.setAdapter(new ArrayAdapter<>(SecondActivity.this, android.R.layout.simple_spinner_dropdown_item, CategoryName));
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                error.printStackTrace();
            }
        });
        int socketTimeout=30000;
        RetryPolicy policy=new DefaultRetryPolicy(socketTimeout, DefaultRetryPolicy.DEFAULT_MAX_RETRIES, DefaultRetryPolicy.DEFAULT_BACKOFF_MULT);
        stringRequest.setRetryPolicy(policy);

        requestQueue.add(stringRequest);


    }

微调器 2 从服务器加载 JSON 数据的代码

private void loadSpinnerData2(String url) {

    RequestQueue requestQueue=Volley.newRequestQueue(getApplicationContext());
    StringRequest stringRequest=new StringRequest(Request.Method.GET, url, new Response.Listener<String>() {
        @Override
        public void onResponse(String response) {




            try {
                JSONObject jsonObject=new JSONObject(response);

                if (jsonObject.getInt("success") == 1) {

                    JSONArray jsonArray=jsonObject.getJSONArray("Name");
                    for (int i=0; i < jsonArray.length(); i++) {
                        JSONObject jsonObject1=jsonArray.getJSONObject(i);

                        String clientName=jsonObject1.getString("ClientName");
                        ClientName.add(clientName);
                    }
                }
                spinner2.setAdapter(new ArrayAdapter<>(SecondActivity.this, android.R.layout.simple_spinner_dropdown_item, ClientName));
            } catch (JSONException e) {
                e.printStackTrace();
            }
        }
    }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            error.printStackTrace();
        }
    });
    int socketTimeout=30000;
    RetryPolicy policy=new DefaultRetryPolicy(socketTimeout, DefaultRetryPolicy.DEFAULT_MAX_RETRIES, DefaultRetryPolicy.DEFAULT_BACKOFF_MULT);
    stringRequest.setRetryPolicy(policy);

    requestQueue.add(stringRequest);
}

Answer 1

将以下行添加到 onItemSelected 微调器方法的顶部。

  if(i==0){
    ///Here you need to show the error msg for the first item selected
    Log.v("ERROR","Please select an item callded");

    //return is used the break the flow of the app so the code below does not run in this case
    return;

    }

Answer 2

将您的项目添加到第一个位置。在 Spinner 上添加一个 Item Selected Check Listener 并添加一个检查是否选择的值是第一个。如果先显示一条消息

spinner.setOnItemSelectedListener(new OnItemSelectedListener() {
    @Override
    public void onItemSelected(AdapterView<?> parentView, View selectedItemView, int position, long id) {
        // your code here
        if(position==0)
            Toast.makeText(getContext,"Please select a value",Toast.LENGTH_LONG).show()
    }

    @Override
    public void onNothingSelected(AdapterView<?> parentView) {
        // your code here
    }

});

如何将 PLEASE SELECT 错误添加到 JSON Spinner

How to add a PLEASE SELECT error to a JSON Spinner

java

android

spinner

android-studio