如何创建一个COVID-19 Tracker Android应用程序以查看印度任何城市和州的详细信息？

在上一篇文章中，我们讨论了如何创建仅显示Global Stats的COVID-19 Tracker Android应用。在本文中，我们将学习如何创建COVID-19 Tracker Android应用，该应用将显示印度任何州的任何城市的详细信息。诸如-总活跃病例，治愈病例，死亡人数以及任何相应城市的确诊病例总数之类的详细信息。在此应用程序中，让我们跟踪5个城市的演示，一个城市可以根据他/她的需求进行更改。

方法

步骤1：创建一个新项目

要在Android Studio中创建新项目，请参阅如何在Android Studio中创建/启动新项目。请注意，选择Java作为编程语言。

步骤2：现在添加一些文件，然后再编写XML和Java代码

• 转到应用程序-> res->值-> colors.xml部分，然后设置应用程序的颜色。
• 这些颜色用于各种地方的应用程序中。

colors.xml

    #024265
    #024265
    #05af9b
  
    #fb7268
    #ededf2
    #E3E0E0
  
    #FFA726
    #66BB6A
    #EF5350
    #29B6F6

• 转到Gradle脚本-> build.gradle(模块：应用程序)部分，导入以下依赖项，然后单击“立即同步”按钮以同步APP。
• 要了解有关Volley Library的更多信息，请单击此处。

implementation ‘com.android.volley:volley:1.1.1’

• 现在转到应用程序->清单-> AndroidManifests.xml部分，并允许“ Internet Permission ”，因为此应用程序将使用Internet权限。

第3步：使用JSON解析从网站获取数据

• 单击此URL- https://api.covid19india.org/state_district_wise.json
• 它将显示整个国家的数据，在这里，我们将仅从此处获取数据。

步骤4：设计activity_main.xml的布局

1. 转到应用-> res->布局-> activity_main.xml
2. 向布局添加TextView：在屏幕顶部显示GEEKSFORGEEKS。
3. 将ListView添加到布局：在屏幕上显示跟踪详细信息的城市列表。

输出界面：

步骤5：为ListView设计布局

1. 通过右键单击res文件夹内的布局文件夹来创建新的布局
2. 然后单击布局资源文件并设置名称testing.xml
3. 单击完成保存
4. 单击testing.xml并为ListView启动设计UI布局
5. testing.xml中使用的Drawable文件为“ arrow arrow ”。转到drawable-> New-> Vector Asset并搜索“ arrow arrow up”并将其添加到您的文件中。

输出界面：

第6步：创建一个新的Java类，以获取要从网站获取的数据

1. 创建一个新的Java类，将其命名为Model。Java
2. 使用getter和setter函数来为您要从网站获取的数据创建一个函数。

模型。Java

public class Model {
    private String name, total, death, cured, active, incAct, incDec, incRec;
  
    public Model(String name, String total, String death, String cured,
                 String active, String incAct, String incDec, String incRec)
    {
        this.name = name;
        this.total = total;
        this.death = death;
        this.cured = cured;
        this.active = active;
        this.incAct = incAct;
        this.incDec = incDec;
        this.incRec = incRec;
    }
  
    public String getIncAct() 
    {
        return incAct;
    }
  
    public void setIncAct(String incAct) 
    {
        this.incAct = incAct;
    }
  
    public String getIncDec() 
    {
        return incDec;
    }
  
    public void setIncDec(String incDec) 
    {
        this.incDec = incDec;
    }
  
    public String getIncRec() 
    {
        return incRec;
    }
  
    public void setIncRec(String incRec)
    {
        this.incRec = incRec;
    }
  
    public String getName() 
    {
        return name;
    }
  
    public void setName(String name)
    {
        this.name = name;
    }
  
    public String getTotal() 
    {
        return total;
    }
  
    public void setTotal(String total)
    {
        this.total = total;
    }
  
    public String getDeath() 
    {
        return death;
    }
  
    public void setDeath(String death) 
    {
        this.death = death;
    }
  
    public String getCured() 
    {
        return cured;
    }
  
    public void setCured(String cured)
    {
        this.cured = cured;
    }
  
    public String getActive()
    {
        return active;
    }
  
    public void setActive(String active)
    {
        this.active = active;
    }
}

步骤7：创建适配器类

现在创建一个新的Java适配器类，以将已获取的数据放入之前创建的ListView中。

Java

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import java.util.List;
  
// Create A Class Adapter
public class Adapter extends ArrayAdapter {
    private Context context;
    private List modelList;
      
    public Adapter(Context context, List modelList) {
        super(context, R.layout.testing, modelList);
          
        this.context = context;
        this.modelList = modelList;
    }
  
    @NonNull
    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
  
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.testing, null,true);
  
        // In this step we connect the XML with Java File
        TextView state = view.findViewById(R.id.state);
        TextView active = view.findViewById(R.id.active);
        TextView cured = view.findViewById(R.id.cured);
        TextView death = view.findViewById(R.id.death);
        TextView total = view.findViewById(R.id.total);
        TextView incactive = view.findViewById(R.id.incactive);
        TextView inccured = view.findViewById(R.id.inccured);
        TextView incdeath = view.findViewById(R.id.incdeath);
  
        // Adding Data to modellist
        state.setText(modelList.get(position).getName());
        active.setText(modelList.get(position).getActive());
        cured.setText(modelList.get(position).getCured());
        death.setText(modelList.get(position).getDeath());
        total.setText(modelList.get(position).getTotal());
        incactive.setText(modelList.get(position).getIncAct());
        inccured.setText(modelList.get(position).getIncRec());
        incdeath.setText(modelList.get(position).getIncDec());
  
        return view;
    }
}

步骤8：使用MainActivity。 Java文件

在此文件中，我们将使用Volley库。请参阅代码内的注释以了解代码。

主要活动。Java

import android.os.Bundle;
import android.widget.ListView;
import android.widget.Toast;
import androidx.appcompat.app.AppCompatActivity;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.List;
  
public class MainActivity extends AppCompatActivity {
  
    ListView listView;
  
    public static List modelList = new ArrayList<>();
    Model model;
    Adapter adapter;
  
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
  
        listView = findViewById(R.id.listView);
        fetchData();
  
    }
  
    private void fetchData() {
        // The Link Through Which We Can Fetch Data
        String url = "https://api.covid19india.org/state_district_wise.json";
  
        StringRequest request = new StringRequest(Request.Method.GET, url, new Response.Listener() {
            @Override
            public void onResponse(String response) {
  
                try {
                    // Creating JSON Object
                    JSONObject object = new JSONObject(response);
  
                    // From that object we are fetching data
                    JSONObject object1 = object.getJSONObject("Uttar Pradesh");
                    JSONObject object2 = object1.getJSONObject("districtData");
                    JSONObject object3 = object2.getJSONObject("Prayagraj");
                    JSONObject object4 = object3.getJSONObject("delta");
  
  
                    String active = object3.getString("active");
                    String confirmed = object3.getString("confirmed");
                    String deceased = object3.getString("deceased");
                    String recovered = object3.getString("recovered");
  
                    String confInc = object4.getString("confirmed");
                    String confDec = object4.getString("deceased");
                    String confRec = object4.getString("recovered");
  
                    model = new Model("Prayagraj", confirmed, deceased, recovered, active,
                                                                      confInc, confDec, confRec);
                    // placing data into the app using AdapterClass
                    modelList.add(model);
  
                    // Creating JSON Object
                    object3 = object2.getJSONObject("Ballia");
  
                    // From that object we are fetching data
                    active = object3.getString("active");
                    confirmed = object3.getString("confirmed");
                    deceased = object3.getString("deceased");
                    recovered = object3.getString("recovered");
                    object4 = object3.getJSONObject("delta");
                    confInc = object4.getString("confirmed");
                    confDec = object4.getString("deceased");
                    confRec = object4.getString("recovered");
  
                    model = new Model("Ballia", confirmed, deceased, recovered, active,
                                                                   confInc, confDec, confRec);
                    // placing data into the app using AdapterClass
                    modelList.add(model);
  
                    // Creating JSON Object
                    object3 = object2.getJSONObject("Lucknow");
  
                    // From that object we are fetching data
                    active = object3.getString("active");
                    confirmed = object3.getString("confirmed");
                    deceased = object3.getString("deceased");
                    recovered = object3.getString("recovered");
                    object4 = object3.getJSONObject("delta");
  
                    confInc = object4.getString("confirmed");
                    confDec = object4.getString("deceased");
                    confRec = object4.getString("recovered");
  
                    model = new Model("Lucknow", confirmed, deceased, recovered, active,
                                                                    confInc, confDec, confRec);
                    // placing data into the app using AdapterClass
                    modelList.add(model);
  
                    // Creating JSON Object
                    object3 = object2.getJSONObject("Varanasi");
  
                    // From that object we are fetching data
                    active = object3.getString("active");
                    confirmed = object3.getString("confirmed");
                    deceased = object3.getString("deceased");
                    recovered = object3.getString("recovered");
                    object4 = object3.getJSONObject("delta");
  
                    confInc = object4.getString("confirmed");
                    confDec = object4.getString("deceased");
                    confRec = object4.getString("recovered");
  
                    model = new Model("Varanasi", confirmed, deceased, recovered, active,
                                                                    confInc, confDec, confRec);
                    // placing data into the app using AdapterClass
                    modelList.add(model);
  
                    // Creating JSON Object
                    object3 = object2.getJSONObject("Agra");
  
                    // From that object we are fetching data
                    active = object3.getString("active");
                    confirmed = object3.getString("confirmed");
                    deceased = object3.getString("deceased");
                    recovered = object3.getString("recovered");
                    object4 = object3.getJSONObject("delta");
                    confInc = object4.getString("confirmed");
                    confDec = object4.getString("deceased");
                    confRec = object4.getString("recovered");
  
                    model = new Model("Agra", confirmed, deceased, recovered, active,
                                                                 confInc, confDec, confRec);
                    // placing data into the app using AdapterClass
                    modelList.add(model);
  
                    adapter = new Adapter(MainActivity.this, modelList);
                    listView.setAdapter(adapter);
  
                    // In case of error it will run
                }   catch (JSONException e) {
                    e.printStackTrace();
                }
  
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                // In case of error it will run
                Toast.makeText(MainActivity.this, error.getMessage(), Toast.LENGTH_SHORT).show();
            }
        });
  
        RequestQueue requestQueue = Volley.newRequestQueue(this);
        requestQueue.add(request);
    }
}

输出

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