ConnectivityManage——基础用法（一）

ConnectivityManage基础用法（一）

判断是否有网络连接

 ConnectivityManager connectivityManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
            NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
            if (networkInfo!=null&&networkInfo.isAvailable()){
                Toast.makeText(context,"network is available",Toast.LENGTH_SHORT).show();
            }else {
                Toast.makeText(context, "network is unavailable", Toast.LENGTH_SHORT).show();
            }

ConnectivityManage 是一个专门用来管理网络连接的服务类

调用它的getActivieNetworkInfo()方法获取到NetworkInfo的实例

通过NetworkInfo 判断是否连接网络

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判断网络连接 就离不开 广播了

动态注册一个广播（T。T）代码如下

public class MainActivity extends AppCompatActivity {
    private IntentFilter intentFilter;
    private NetwokChangeReceiver netwokChangeReceiver;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        intentFilter = new IntentFilter();//IntentFilter 是隐式Intent的过滤器
        intentFilter.addAction("android.net.conn.CONNECTIVITY_CHANGE"); //设置过滤条件
        netwokChangeReceiver = new NetwokChangeReceiver(); //实例化一条广播
        registerReceiver(netwokChangeReceiver,intentFilter);//注册广播
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        unregisterReceiver(netwokChangeReceiver); //取消注册广播
    }

    class NetwokChangeReceiver extends BroadcastReceiver{

        @Override
        public void onReceive(Context context, Intent intent) {
            ConnectivityManager connectivityManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
            NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
            if (networkInfo!=null&&networkInfo.isAvailable()){
                Toast.makeText(context,"network is available",Toast.LENGTH_SHORT).show();
            }else {
                Toast.makeText(context, "network is unavailable", Toast.LENGTH_SHORT).show();
            }
        }
    }
}

还需要在AndroidManifest.xml中声明访问系统网络的权限