Broadcast组件——收发广播应用——监听系统广播——接收网络变更广播

骑猪看日落 2023-09-28 16:27 3阅读 0赞

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布局：

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代码：

package com.example.myapplication;
    
    import android.content.BroadcastReceiver;
    import android.content.Context;
    import android.content.Intent;
    import android.content.IntentFilter;
    import android.net.NetworkInfo;
    import android.os.Bundle;
    import android.widget.TextView;
    
    import androidx.appcompat.app.AppCompatActivity;
    
    public class MainActivity extends AppCompatActivity
    {
    
        private TextView tv_network; // 声明一个文本视图对象
    
        private String desc = "开始侦听网络变更广播，请开关WLAN或者数据连接，再观察广播结果";
    
        @Override
        protected void onCreate(Bundle savedInstanceState)
        {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
    
    
            tv_network = findViewById(R.id.tv_network);
            tv_network.setText(desc);
        }
    
        @Override
        protected void onStart()
        {
            super.onStart();
            networkReceiver = new NetworkReceiver(); // 创建一个网络变更的广播接收器
    
            // 创建一个意图过滤器，只处理网络状态变化的广播
            IntentFilter filter = new IntentFilter("android.net.conn.CONNECTIVITY_CHANGE");
    
            registerReceiver(networkReceiver, filter); // 注册接收器，注册之后才能正常接收广播
        }
    
        @Override
        protected void onStop()
        {
            super.onStop();
    
            unregisterReceiver(networkReceiver); // 注销接收器，注销之后就不再接收广播
        }
    
        private NetworkReceiver networkReceiver; // 声明一个网络变更的广播接收器实例
    
        // 定义一个网络变更的广播接收器
        private class NetworkReceiver extends BroadcastReceiver
        {
            // 一旦接收到网络变更的广播，马上触发接收器的onReceive方法
            @Override
            public void onReceive(Context context, Intent intent)
            {
                if (intent != null)
                {
                    NetworkInfo networkInfo = intent.getParcelableExtra("networkInfo");
    
                    String networkClass = NetworkUtil.getNetworkClass(networkInfo.getSubtype());
    
                    desc = String.format("%s\n%s 收到一个网络变更广播，网络大类为%s，" + "网络小类为%s，网络制式为%s，网络状态为%s", desc, DateUtil.getNowTime(), networkInfo.getTypeName(), networkInfo.getSubtypeName(), networkClass, networkInfo.getState().toString());
    
                    tv_network.setText(desc);
                }
            }
        }
    
    }

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NetworkUtil：

package com.example.myapplication;
    
    import android.telephony.TelephonyManager;
    
    public class NetworkUtil
    {
        // 获取数据连接的制式类型
        public static String getNetworkClass(int subType)
        {
            switch (subType)
            {
                case TelephonyManager.NETWORK_TYPE_GPRS:
                case TelephonyManager.NETWORK_TYPE_EDGE:
                case TelephonyManager.NETWORK_TYPE_CDMA:
                case TelephonyManager.NETWORK_TYPE_1xRTT:
                case TelephonyManager.NETWORK_TYPE_IDEN:
                    return "2G";
                case TelephonyManager.NETWORK_TYPE_UMTS:
                case TelephonyManager.NETWORK_TYPE_EVDO_0:
                case TelephonyManager.NETWORK_TYPE_EVDO_A:
                case TelephonyManager.NETWORK_TYPE_HSDPA:
                case TelephonyManager.NETWORK_TYPE_HSUPA:
                case TelephonyManager.NETWORK_TYPE_HSPA:
                case TelephonyManager.NETWORK_TYPE_EVDO_B:
                case TelephonyManager.NETWORK_TYPE_EHRPD:
                case TelephonyManager.NETWORK_TYPE_HSPAP:
                    return "3G";
                case TelephonyManager.NETWORK_TYPE_LTE:
                    return "4G";
                case TelephonyManager.NETWORK_TYPE_NR:
                    return "5G";
                default:
                    return "未知";
            }
        }
    }

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DateUtil：

package com.example.myapplication;
    
    import android.annotation.SuppressLint;
    import android.text.TextUtils;
    
    import java.text.SimpleDateFormat;
    import java.util.Calendar;
    import java.util.Date;
    
    @SuppressLint("SimpleDateFormat")
    public class DateUtil
    {
        // 获取当前的日期时间
        public static String getNowDateTime(String formatStr)
        {
            String format = formatStr;
            if (TextUtils.isEmpty(format))
            {
                format = "yyyyMMddHHmmss";
            }
    
            SimpleDateFormat sdf = new SimpleDateFormat(format);
            return sdf.format(new Date());
        }
    
        // 获取当前的时间
        public static String getNowTime()
        {
            SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");
            return sdf.format(new Date());
        }
    
        // 获取当前的时间(精确到毫秒)
        public static String getNowTimeDetail()
        {
            SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss.SSS");
            return sdf.format(new Date());
        }
    
        public static String getNowDate()
        {
            SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd");
            return sdf.format(new Date());
        }
    
        public static String getDate(Calendar calendar)
        {
            Date date = calendar.getTime();
            // 创建一个日期格式化的工具
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
            // 将当前日期时间按照指定格式输出格式化后的日期时间字符串
            return sdf.format(date);
        }
    
        public static String getMonth(Calendar calendar)
        {
            Date date = calendar.getTime();
            // 创建一个日期格式化的工具
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM");
            // 将当前日期时间按照指定格式输出格式化后的日期时间字符串
            return sdf.format(date);
        }
    
        public static Date formatString(String strTime)
        {
            Date date = new Date();
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    
            try {
                date = sdf.parse(strTime);
            } catch (Exception e) {
                e.printStackTrace();
            }
    
            return date;
        }
    
    }

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