第23天~又是JSON＋ListView

又是JSON

开新专案

准备XML档＋ListView

放好ID

准备一个TXT档案-

把txt档案贴到java档里

先宣告变数-

TXT档案贴上会自动解析成字串格式-

{
    title:JSONParserTutorial,
    array:[
    {
       company:Google
    },
    {
       company:Facebook
    },
    {
       company:LinkedIn
    },
    {
       company:Microsoft
    },
    {
       company:Apple
    },
    ],

       nested:{
       flag:ture,
       random_number:1

    }
}

绿色都是要得~

宣告按钮跟容器-

package com.huang.myjson2;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.widget.ListView;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {
    //宣告变数
    String json_string = "{\n" +
            "    title:JSONParserTutorial,\n" +
            "    array:[\n" +
            "    {\n" +
            "       company:Google\n" +
            "    },\n" +
            "    {\n" +
            "       company:Facebook\n" +
            "    },\n" +
            "    {\n" +
            "       company:LinkedIn\n" +
            "    },\n" +
            "    {\n" +
            "       company:Microsoft\n" +
            "    },\n" +
            "    {\n" +
            "       company:Apple\n" +
            "    },\n" +
            "    ],\n" +
            "\n" +
            "       nested:{\n" +
            "       flag:ture,\n" +
            "       random_number:1\n" +
            "\n" +
            "    }\n" +
            "}";

    ListView listView;
    ArrayList<String> items;

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

        //初始化
        
    }
}

再来是初始化-

反红是因为要抛例外-点到红色线

长这样


package com.huang.myjson2;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.widget.ListView;

import org.json.JSONException;
import org.json.JSONObject;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {
    //宣告变数
    String json_string = "{\n" +
            "    title:JSONParserTutorial,\n" +
            "    array:[\n" +
            "    {\n" +
            "       company:Google\n" +
            "    },\n" +
            "    {\n" +
            "       company:Facebook\n" +
            "    },\n" +
            "    {\n" +
            "       company:LinkedIn\n" +
            "    },\n" +
            "    {\n" +
            "       company:Microsoft\n" +
            "    },\n" +
            "    {\n" +
            "       company:Apple\n" +
            "    },\n" +
            "    ],\n" +
            "\n" +
            "       nested:{\n" +
            "       flag:ture,\n" +
            "       random_number:1\n" +
            "\n" +
            "    }\n" +
            "}";

    ListView listView;
    ArrayList<String> items;

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

        //初始化
        listView = findViewById(R.id.list_view);
        items = new ArrayList<>();

        try {
            JSONObject object = new JSONObject(json_string);
        } catch (JSONException e) {
            e.printStackTrace();
        }


    }
}

如何把它转到listView

package com.huang.myjson2;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.widget.ListView;

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

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {
    //宣告变数
    String json_string = "{\n" +
            "    title:JSONParserTutorial,\n" +
            "    array:[\n" +
            "    {\n" +
            "       company:Google\n" +
            "    },\n" +
            "    {\n" +
            "       company:Facebook\n" +
            "    },\n" +
            "    {\n" +
            "       company:LinkedIn\n" +
            "    },\n" +
            "    {\n" +
            "       company:Microsoft\n" +
            "    },\n" +
            "    {\n" +
            "       company:Apple\n" +
            "    },\n" +
            "    ],\n" +
            "\n" +
            "       nested:{\n" +
            "       flag:ture,\n" +
            "       random_number:1\n" +
            "\n" +
            "    }\n" +
            "}";

    ListView listView;
    ArrayList<String> items;

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

        //初始化
        listView = findViewById(R.id.list_view);
        items = new ArrayList<>();

        try {
            JSONObject object = new JSONObject(json_string);
            JSONArray array = object.getJSONArray("array");
            for(int i;i<array.length();i++){
                JSONObject o=array.getJSONObject(i);
                items.add(o.getString("company"));
            }

        } catch (JSONException e) {
            e.printStackTrace();
        }
        //把资料按照格式转好

    }
}

//把资料按照格式转好

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;

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

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {
    //宣告变数
    String json_string = "{       \n" +
            "\ttitle:JSONParserTutorial,       \n" +
            "\tarray:[       \n" +
            "  {       \n" +
            "\tcompany:Google           \n" +
            "  },       \n" +
            "  {       \n" +
            "\tcompany:Facebook           \n" +
            "  },       \n" +
            "  {       \n" +
            "\tcompany:LinkedIn           \n" +
            "  },       \n" +
            "  {       \n" +
            "\tcompany:Microsoft           \n" +
            "  },       \n" +
            "  {       \n" +
            "\tcompany:Apple           \n" +
            "  }       \n" +
            "  ],       \n" +
            "\tnested:{       \n" +
            "\tflag:true,       \n" +
            "\trandom_number:1       \n" +
            "  }       \n" +
            "}  ";
    ListView listView;
    ArrayList<String> items;

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

        listView = findViewById(R.id.list_view);
        items = new ArrayList<String>();

        try {
            JSONObject object = new JSONObject(json_string);
            JSONArray array = object.getJSONArray("array");
            for(int i=0; i<array.length(); i++){
                JSONObject o = array.getJSONObject(i);
                items.add(o.getString("company"));
            }
            //取得其他key的内容-----------------------
            JSONObject oo = object.getJSONObject("nested");
            String msg = oo.getString("flag");
            boolean msg2 = oo.getBoolean("flag");
            Toast.makeText(MainActivity.this, msg2+"", Toast.LENGTH_SHORT).show();

        } catch (JSONException e) {
            e.printStackTrace();
        }

        ArrayAdapter<String> adapter = new ArrayAdapter<>(
                this,
                android.R.layout.simple_list_item_1,
                items
        );
        listView.setAdapter(adapter);

    }
}

这里我的模拟器RUN不出来.
所以我自己上网找另外一个做看看

後来发现是要用手机看-

所以我自己上网找另外一个做看看

java 档

package com.huang.myapplication;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.ListView;

public class MainActivity extends AppCompatActivity {

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

        ListView listView=(ListView) findViewById(R.id.listview);

        String[] str ={"新北市","台北市","台中市","台南市","高雄市"};

        ArrayAdapter adapter =new ArrayAdapter(this,
                android.R.layout.simple_list_item_1,
                str);

        listView.setAdapter(adapter);
    }
}

xml档

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <ListView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentBottom="true"
        android:id="@+id/listview" />

</LinearLayout>

也是用自己的手机测试