Android 网络地址之实现检查主机名的功能

<?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"
    android:orientation="vertical"
    android:padding="5dp"
    tools:context=".InetAddressActivity">
    <EditText
        android:id="@+id/edit_address"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:background="@drawable/edit_style"
        android:text="www.163.com" />
    <Button
        android:id="@+id/btn_hostName_check"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:layout_marginTop="5dp"
        android:text="检查主机名"
        android:textColor="@color/black"
        android:textSize="20sp" />
    <TextView
        android:id="@+id/tv_desc"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textColor="@color/black"
        android:textSize="15sp" />
</LinearLayout>

public class InetAddressActivity extends AppCompatActivity implements View.OnClickListener {
    private EditText edit_address;
    private TextView tv_desc;
    private Button btn_hostName_check;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_inet_address);
        edit_address = findViewById(R.id.edit_address);
        tv_desc = findViewById(R.id.tv_desc);
        btn_hostName_check = findViewById(R.id.btn_hostName_check);
        btn_hostName_check.setOnClickListener(this);
    }
    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.btn_hostName_check:
                String hostName = edit_address.getText().toString();
                //开启子线程 检查主机名
                new CheckThread(hostName).start();
                break;
            default:
                break;
        }
    }
    //创建一个检查结果的接收器Handler
    private Handler handler = new Handler(new Handler.Callback() {
        @Override
        public boolean handleMessage(@NonNull Message msg) {
            tv_desc.setText("主机检查结果如下：\n" + msg.obj);
            return true;
        }
    });
    private class CheckThread extends Thread {
        private String hostName;
        public CheckThread(@NonNull String name) {
            hostName = name;
        }
        @Override
        public void run() {
            //获得一个默认消息对象
            Message message = Message.obtain();
            try {
                //根据主机名获取主机名称对象
                InetAddress inetAddress = InetAddress.getByName(hostName);
                //检查该主机在规定时间内能否连上
                boolean isReachable = inetAddress.isReachable(5000);
                String desc = (isReachable) ? "可以连接" : "无法连接";
                if (isReachable) {
                    desc = String.format("%s\n主机名为：%s\n主机地址为：%s", desc,
                            inetAddress.getHostName(), inetAddress.getHostAddress());
                    message.what = 0; //消息类型
                    message.obj = desc;//消息描述
                }
            } catch (Exception e) {
                e.printStackTrace();
                message.what = -1; //消息类型
                message.obj = e.getMessage(); //消息描述
            }
            // 向接收处理器发送检查结果消息
            handler.sendMessage(message);
        }
    }
}