从.json文件创建下拉菜单

Question

package com.example.root.myapplication;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;

import org.json.JSONArray;
import org.json.JSONException;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

    Button btnCommercial;

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

        final ListView list11 = (ListView) findViewById(R.id.listView1);
        ArrayList<String> authorities = getAuthorities("AuthorityList.json");
        final ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_dropdown_item, authorities);
        btnCommercial = (Button) findViewById(R.id.btnCommercial);
        btnCommercial.setOnClickListener(
                new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {
                        list11.setAdapter(adapter);
                    }
                });
    }

    private ArrayList<String> getAuthorities(String fileName) {
        JSONArray jsonArray = null;
        ArrayList<String> AuthList = new ArrayList<String>();

        try {
            InputStream inputStream = getAssets().open(fileName);       //open the inputStream to the file
            int size = inputStream.available();                         //size of the entire json object
            byte[] data = new byte[size];                               //array that will store all the data
            inputStream.read(data);                                     //reading data into the array for the file
            inputStream.close();                                        //close the input steam
            String json = new String(data, "UTF-8");
            jsonArray = new JSONArray(json);

            if (jsonArray != null) {
                for (int i = 0; i < jsonArray.length(); i++) {
                    AuthList.add(jsonArray.getJSONObject(i).getString("description"));
                }
            }
        } catch (IOException e) {
            e.printStackTrace(); return null;
        } catch (JSONException je) {
            je.printStackTrace(); return null;
        }
        return AuthList;
    }
}

我想创建一个下拉菜单,其中包含我项目中的JSON文件中的数据.我正在努力通过soapui访问我的远程服务器,所以我将.json文件复制到我的项目资产下.代码没有给我一个错误,但我的应用程序将无法运行.我认为问题是我如何打开.json文件或如何访问对象.

先感谢您.

Answer 1

您可以尝试以下函数来获取 JSON 文件的字符串。

public static String AssetJSONFile (String filename, Context context) throws IOException {
        AssetManager manager = context.getAssets();
        InputStream file = manager.open(filename);
        byte[] formArray = new byte[file.available()];
        file.read(formArray);
        file.close();

        return new String(formArray);
    }

然后解析它。如果您的数据足够大，我建议使用一些库（如 LoganSquare 或 Jackson）来解析 JSON 数据。