基于Android Studio 开发作业-1 （mainactivtiy）

package com.example.phoneapplication;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;

public class MainActivity extends AppCompatActivity {

    private ListView phoneList;
    private List<String> stringList= new ArrayList<>();
    private ListAdapter listAdapter;

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

        listAdd();

        phoneList = (ListView) findViewById(R.id.phoneList);
        listAdapter = new ListAdapter(this,stringList);
        phoneList.setAdapter(listAdapter);
        phoneList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                Toast.makeText(MainActivity.this,"拨打用户：user"+position+"的电话",Toast.LENGTH_SHORT).show();
                callPhone(listAdapter.getItem(position));
            }
        });
    }

    private void listAdd() {
        for (int i = 0; i < 20; i++) {
            stringList.add("1888"+random(7));
        }
    }
    public static String random(int places) {
        StringBuilder num = new StringBuilder();
        Random ran = new Random();
        String new_nums = " ";
        for (int i = 0; i < places; i++) {
            StringBuilder nums = num.append(ran.nextInt(10));
            new_nums = nums.toString();
        }
        return new_nums;
    }
    public void callPhone(String phoneNum) {
        Intent intent = new Intent(Intent.ACTION_DIAL);
        Uri data = Uri.parse("tel:" + phoneNum);
        intent.setData(data);
        startActivity(intent);
    }
}