Question

数据来自JSON RESPONSE。在JSON中，每个标记包含多个节点。第二个微调器的相关数据基于First的选择。我的JSON就像这里

如何将JSON和首先所有主要节点解析为First Spinner。然后当User Select点头时，根据选择数据必须反映到第二个Spinner中。请指导我。

@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
                    }
                });
    }
}

Answer 1

此代码可能无法让您了解从API获取JSON中的对象。

你想要做的事情很简单，但我尽量保持通用的东西，以便其他人可以使用这段代码。

代码中表示的spinner由ArrayList WorldPopulation类型填充。您会注意到toString WorldPopulation被{@ 1}}覆盖，可以在ArrayAdapter中使用，以便获取该国家/地区的名称。

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

<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

现在您已在Spinner中填充了数据，您可以利用此功能触发填充的第二个spinner，具体取决于第一个spinner上的选择。

显然我没有看到任何可以告诉我第二个数据来源的链接，我会在这里留下答案直到下次更新。

基于选择的JSON数据到微调器

1 个答案: