在Android上監聽網絡狀態的變更

  開發過程中經常會遇到一種需求，在你的Activity中需要獲得網絡連接的狀態，以便確認下一步的流程，之前設計過一個復雜的方法，后來發現每次網絡狀態發生變化了都會發廣播出來，廣播這是個好東西，有了廣播，我們就可以靈活的去處理了。

    當然，首先要加權限 

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" /> 

這樣，我們寫receiver就可以了。

<receiver
    android:name="NetworkReceiver">
    <intent-filter>
        <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
    </intent-filter>

</receiver> 

public class NetworkReceiver extends BroadcastReceiver {

    protected Context    mContext;

    @Override
    public void onReceive(Context context, Intent intent) {
        mContext = context;
        // 第一種
        ConnectivityManager connectivityManager = (ConnectivityManager) context
                .getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo activeNetInfo = connectivityManager.getActiveNetworkInfo();
        NetworkInfo mobileNetInfo = connectivityManager
                .getNetworkInfo(ConnectivityManager.TYPE_MOBILE);
        showToast("Active Network Type", activeNetInfo);
        showToast("Mobile Network Type", mobileNetInfo);
        // 第二種
        NetworkInfo networkInfo = intent
                .getParcelableExtra(ConnectivityManager.EXTRA_NETWORK_INFO);
        String extraInfo = intent
                .getStringExtra(ConnectivityManager.EXTRA_EXTRA_INFO);
        boolean isFailOver = intent.getBooleanExtra(
                ConnectivityManager.EXTRA_IS_FAILOVER, false);
        boolean noConnectivity = intent.getBooleanExtra(
                ConnectivityManager.EXTRA_NO_CONNECTIVITY, false);
        NetworkInfo otherNetworkInfo = intent
                .getParcelableExtra(ConnectivityManager.EXTRA_OTHER_NETWORK_INFO);
        String reason = intent.getStringExtra(ConnectivityManager.EXTRA_REASON);
        //
        showToast("networkInfo", networkInfo);
        showToast("extraInfo", extraInfo);
        showToast("isFailOver", isFailOver);
        showToast("noConnectivity", noConnectivity);
        showToast("otherNetworkInfo", otherNetworkInfo);
        showToast("reason", reason);
    }

    public void showToast(String info, Object object) {
        if (object == null) {
            return;
        }
        Toast.makeText(mContext, info + " : " + object.toString(), 0).show();
    }

}