根据选择将JSON数据导入微调器 [英] JSON Data into Spinner Based on Selection

问题描述

数据来自JSON RESPONSE.在JSON中，每个标签都包含节点数.第二个微调器中的相关数据基于第一"的选择.我的JSON就像这里

Data is coming form JSON RESPONSE. In JSON, Every Tag contains number of nodes. Relevant data into second spinner is based on selection of First. My JSON Is Like Here

如何解析JSON，以及首先将所有主要节点解析为First Spinner.然后，当用户选择点头时，必须根据选择将数据反映到第二个微调器中.请引导我.

How to Parse JSON and firstly all major nodes into First Spinner. then when User Select that nods, according to selection Data must be reflect into second Spinner. Please guide me .

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    // Download JSON file AsyncTask
    new DownloadJSON().execute();

}

// Download JSON file AsyncTask
private class DownloadJSON extends AsyncTask<Void, Void, Void> {

    @Override
    protected Void doInBackground(Void... params) {
        // Locate the WorldPopulation Class 
        world = new ArrayList<WorldPopulation>();
        // Create an array to populate the spinner 
        worldlist = new ArrayList<String>();
        // JSON file URL address
        jsonobject = JSONfunctions
                .getJSONfromURL("http://www.androidbegin.com/tutorial/jsonparsetutorial.txt");

        try {
            // Locate the NodeList name
            jsonarray = jsonobject.getJSONArray("worldpopulation");
            for (int i = 0; i < jsonarray.length(); i++) {
                jsonobject = jsonarray.getJSONObject(i);

                WorldPopulation worldpop = new WorldPopulation();

                worldpop.setRank(jsonobject.optString("rank"));
                worldpop.setCountry(jsonobject.optString("country"));
                worldpop.setPopulation(jsonobject.optString("population"));
                worldpop.setFlag(jsonobject.optString("flag"));
                world.add(worldpop);

                // Populate spinner with country names
                worldlist.add(jsonobject.optString("country"));

            }
        } catch (Exception e) {
            Log.e("Error", e.getMessage());
            e.printStackTrace();
        }
        return null;
    }

    @Override
    protected void onPostExecute(Void args) {
        // Locate the spinner in activity_main.xml
        Spinner mySpinner = (Spinner) findViewById(R.id.my_spinner);

        // Spinner adapter
        mySpinner
                .setAdapter(new ArrayAdapter<String>(MainActivity.this,
                        android.R.layout.simple_spinner_dropdown_item,
                        worldlist));

        // Spinner on item click listener
        mySpinner
                .setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {

                    @Override
                    public void onItemSelected(AdapterView<?> arg0,
                            View arg1, int position, long arg3) {
                        // TODO Auto-generated method stub
                        // Locate the textviews in activity_main.xml
                        TextView txtrank = (TextView) findViewById(R.id.rank);
                        TextView txtcountry = (TextView) findViewById(R.id.country);
                        TextView txtpopulation = (TextView) findViewById(R.id.population);

                        // Set the text followed by the position 
                        txtrank.setText("Rank : "
                                + world.get(position).getRank());
                        txtcountry.setText("Country : "
                                + world.get(position).getCountry());
                        txtpopulation.setText("Population : "
                                + world.get(position).getPopulation());
                    }

                    @Override
                    public void onNothingSelected(AdapterView<?> arg0) {
                        // TODO Auto-generated method stub
                    }
                });
    }
}

推荐答案

这段代码可能会让您对从JSON填充对象(从API的对象)中填充对象一无所知.

This code can give you little idea about populating your objects from JSON which you get from the API's.

您想做的事情很简单，但我尝试使事情尽可能通用，以便其他人可以使用此代码.

What you want to do is quite simple but i tried to keep things as generic as possible so anyone else ca make a use of this code.

spinner由WorldPopulation类型的ArrayList填充.您会注意到WorldPopulation中的toString被覆盖，可以在ArrayAdapter中使用，因此可以选择国家/地区的名称.

the spinner represented in the code is populated by ArrayList of WorldPopulation type. you will notice that toString of WorldPopulation is overridden that it can be used in the ArrayAdapter so the name of the country will be picked up.

public class LoadDataActivity extends AppCompatActivity {

    private Spinner spinner;
    private ArrayList<WorldPopulation> worldPopulations;

    private TextView rank_TextView;
    private TextView country_TextView;
    private TextView population_TextView;
    private TextView url_TextView;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_load_data);


        spinner = (Spinner) findViewById(R.id.LoadDataActivity_spinner);

        rank_TextView = (TextView) findViewById(R.id.LoadDataActivity_rank_textView);
        country_TextView = (TextView) findViewById(R.id.LoadDataActivity_country_textView);
        population_TextView = (TextView) findViewById(R.id.LoadDataActivity_population_textView);
        url_TextView = (TextView) findViewById(R.id.LoadDataActivity_url_textView);

        spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                WorldPopulation population = (WorldPopulation) spinner.getItemAtPosition(position);
                rank_TextView.setText("" + population.getRank());
                country_TextView.setText("" + population.getCountry());
                population_TextView.setText("" + population.getPopulation());
                url_TextView.setText("" + population.getFlag());
            }

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

            }
        });

        new DownloadData().execute();
    }


    private class DownloadData extends AsyncTask<Void, Void, Void> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
        }

        @Override
        protected Void doInBackground(Void... params) {

            try {
                worldPopulations = new ArrayList<>();
                URL url = new URL("http://www.androidbegin.com/tutorial/jsonparsetutorial.txt");
                HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
                httpURLConnection.connect();
                String result = IOUtils.toString(httpURLConnection.getInputStream());
                System.out.println("" + result);
                JSONObject jsonObject = new JSONObject(result);
                JSONArray jsonArray = jsonObject.getJSONArray("worldpopulation");
                for (int i = 0; i < jsonArray.length(); i++) {
                    JSONObject singleItem = jsonArray.getJSONObject(i);
                    WorldPopulation population = new WorldPopulation();
                    population.rank = singleItem.getString("rank");
                    population.country = singleItem.getString("country");
                    population.population = singleItem.getString("population");
                    population.flag = singleItem.getString("flag");
                    worldPopulations.add(population);
                }

                Log.d("TAG", "" + result);
                Log.d("TAG", "size: " + worldPopulations.size());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return null;
        }

        @Override
        protected void onPostExecute(Void aVoid) {
            super.onPostExecute(aVoid);
            ArrayAdapter<WorldPopulation> adapter = new ArrayAdapter<WorldPopulation>(getApplicationContext(), android.R.layout.simple_spinner_dropdown_item, worldPopulations);
            adapter.setDropDownViewResource(android.R.layout.simple_list_item_1);
            spinner.setAdapter(adapter);
        }
    }

    class WorldPopulation {
        private String rank;
        private String country;
        private String population;
        private String flag;

        public String getRank() {
            return rank;
        }

        public void setRank(String rank) {
            this.rank = rank;
        }

        public String getCountry() {
            return country;
        }

        public void setCountry(String country) {
            this.country = country;
        }

        public String getPopulation() {
            return population;
        }

        public void setPopulation(String population) {
            this.population = population;
        }

        public String getFlag() {
            return flag;
        }

        public void setFlag(String flag) {
            this.flag = flag;
        }

        @Override
        public String toString() {
            return country;
        }
    }

}

activity_load_data.xml

activity_load_data.xml

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_margin="4dp"
    android:orientation="vertical">


    <Spinner
        android:id="@+id/LoadDataActivity_spinner"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:layout_margin="4dp" />

    <TextView
        android:id="@+id/LoadDataActivity_rank_textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="4dp"
        android:textAppearance="?android:attr/textAppearanceMedium" />

    <TextView
        android:id="@+id/LoadDataActivity_country_textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="4dp"
        android:textAppearance="?android:attr/textAppearanceMedium" />

    <TextView
        android:id="@+id/LoadDataActivity_population_textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="4dp"
        android:textAppearance="?android:attr/textAppearanceMedium" />

    <TextView
        android:id="@+id/LoadDataActivity_url_textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="4dp"
        android:textAppearance="?android:attr/textAppearanceMedium" />
</LinearLayout>

输出

现在您已经在Spinner中填充了数据，您可以利用它来触发第二个spinner的填充，具体取决于第一个spinner的选择.

Now that you have the data being populated in the Spinner you can utilize this to trigger the populate second spinner depending on the selection on the first spinner.

显然，我没有看到任何链接可以告诉我第二个数据源，我将在此处保留答案直到下一次更新.

Apparently I didn't see any link that would tell me about the second source of data, i will leave the answer here until next update.

这篇关于根据选择将JSON数据导入微调器的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！