Android Spinner不调用侦听器方法

Question

I'm trying to implement spinner so that when item selected changes, it also changes couple of TextView-s depending on the selected item. But currently spinner doesn't call on its listener, nor does it show the selected item, but it shows them in the drop down list.

import android.app.ProgressDialog;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.AdapterView.OnItemSelectedListener;
import com.android.volley.Request;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest; 
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class ShowData extends AppCompatActivity implements OnItemSelectedListener {

    private TextView temp, mass, humid;
    private ArrayList<String> list;
    private Spinner spinner;
    private JSONObject jObj;
    private  JSONArray array;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate( savedInstanceState );
        setContentView( R.layout.activity_show_data );
        temp = (TextView) findViewById(R.id.temp);
        mass = (TextView) findViewById(R.id.mass);
        humid = (TextView) findViewById(R.id.humid);
        list = new ArrayList<String>();
        //fill() gets data from server and puts it into "list"
        fill();
        addItemsToSpinner();
        addListenerToSpinner();
    }

    private void addItemsToSpinner(){
        spinner = (Spinner)findViewById(R.id.date);
        ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_dropdown_item, list);
        dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner.setAdapter(dataAdapter);

    }

    private void  addListenerToSpinner(){
        spinner = (Spinner)findViewById(R.id.date);
        spinner.setOnItemSelectedListener(this);
    }

    private void fill() {
      //this portion works so i didnt include it 
      //gets data from the server and fills the list
    }

    public void onItemSelected(AdapterView<?> parent, View view, int pos, long id){
        Toast.makeText(getApplicationContext(), "Clicked on: " + list.get(pos), Toast.LENGTH_SHORT).show();
        temp.setText("listener works!");
        try {
            String temperature = array.getJSONObject(pos).getString("temp");
            String humidity = array.getJSONObject(pos).getString("humidity");
            String massStr = array.getJSONObject(pos).getString("mass");
            temp.setText(temperature);
            humid.setText(humidity);
            mass.setText(massStr);
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }

    public void onNothingSelected(AdapterView<?> arg0) {
    }

}

XML:

[<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.lukak.pcele_mobitel.ShowData">

    <Spinner
        android:id="@+id/date"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" />
        android:singleLine="true" />


    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:id="@+id/mass"
        android:layout_below="@+id/date"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="26dp"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:id="@+id/temp"
        android:layout_below="@+id/mass"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="36dp" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:id="@+id/humid"
        android:layout_below="@+id/temp"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="36dp" />


</RelativeLayout>][1]

not showing selected item on spinner

showing available items when clicked on spinner

Answer 1

Try doing it this way:

No need of addListenerToSpinner() method.

onCreate:

onCreate{
spinner = (Spinner)findViewById(R.id.date);
spinner.setOnItemSelectedListener(this);
}

addItemsToSpinner

private void addItemsToSpinner(){
        spinner = (Spinner)findViewById(R.id.date); // ****** remove this.....
        ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_dropdown_item, list);
        dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner.setAdapter(dataAdapter);
}

onItemSelected

public void onItemSelected{
Toast.makeText(getApplicationContext(), "Clicked on: " + list.get(pos), Toast.LENGTH_SHORT).show();
....
}

Answer 2

add this modified code.

 protected void onCreate(Bundle savedInstanceState) {
    super.onCreate( savedInstanceState );
    setContentView( R.layout.activity_show_data );
    temp = (TextView) findViewById(R.id.temp);
    mass = (TextView) findViewById(R.id.mass);
    humid = (TextView) findViewById(R.id.humid);
    spinner = (Spinner)findViewById(R.id.date);
    list = new ArrayList<String>();
    //fill() gets data from server and puts it into "list"
    fill();
    addItemsToSpinner();
    spinner.setOnItemSelectedListener(this);
}

private void addItemsToSpinner(){

    ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, list);
    dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spinner.setAdapter(dataAdapter);

}


private void fill() {
  //this portion works so i didnt include it 
  //gets data from the server and fills the list
}

public void onItemSelected(AdapterView<?> parent, View view, int pos, long id){
    Toast.makeText(getApplicationContext(), "Clicked on: " + list.get(pos), Toast.LENGTH_SHORT).show();
    temp.setText("listener works!");
    try {
        String temperature = array.getJSONObject(pos).getString("temp");
        String humidity = array.getJSONObject(pos).getString("humidity");
        String massStr = array.getJSONObject(pos).getString("mass");
        temp.setText(temperature);
        humid.setText(humidity);
        mass.setText(massStr);
    } catch (JSONException e) {
        e.printStackTrace();
    }
}

public void onNothingSelected(AdapterView<?> arg0) {
}

}