Android 獲取手機IP(3G/4G/WIFI/無網路)

1.activity_main.xml

    <TextView
        android:id="@+id/nametextview"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginBottom="200dp"
        android:textSize="20sp" />

    <TextView
        android:id="@+id/ipTextView"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginBottom="100dp"
        android:textSize="20sp" />

2.MainActivity.java,連接手機網路3G/4G/WIFI/無網路

public class MainActivity extends AppCompatActivity {
    private TextView ipTextView = null;
    private TextView nameTextView = null;
    private ConnectivityManager mConnectivityManager = null;
    private NetworkInfo mActiveNetInfo = null;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        nameTextView = (TextView) findViewById(R.id.nametextview);
        ipTextView = (TextView) findViewById(R.id.ipTextView);

        mConnectivityManager = (ConnectivityManager)getSystemService(CONNECTIVITY_SERVICE) ;//獲取系統的連接服務
        mActiveNetInfo = mConnectivityManager.getActiveNetworkInfo();//獲取網路連接的資訊

        if(mActiveNetInfo==null)
            myDialog();
        else
            setUpInfo();
    }
    //獲取ip地址
    public String getIPAddress() {
        NetworkInfo info = mConnectivityManager.getActiveNetworkInfo();
        if (info != null && info.isConnected()) {
            if ((info.getType() == ConnectivityManager.TYPE_MOBILE) || (info.getType() == ConnectivityManager.TYPE_WIFI) ){//當前使用2G/3G/4G網路
                try {
                    for (Enumeration<NetworkInterface> en = NetworkInterface.getNetworkInterfaces(); en.hasMoreElements(); ) {
                        NetworkInterface intf = en.nextElement();
                        for (Enumeration<InetAddress> enumIpAddr = intf.getInetAddresses(); enumIpAddr.hasMoreElements(); ) {
                            InetAddress inetAddress = enumIpAddr.nextElement();
                            if (!inetAddress.isLoopbackAddress() && inetAddress instanceof Inet4Address) {
                                return inetAddress.getHostAddress();
                            }
                        }
                    }
                }
                catch (SocketException e) {
                    e.printStackTrace();
                }
            }
        }
        else { //當前無網路連接,請在設定中打開網路
            return null;
        }
        return null;
    }

    public void setUpInfo()  {
        if(mActiveNetInfo.getType()==ConnectivityManager.TYPE_WIFI)  {
            nameTextView.setText("網路型別：WIFI");
            ipTextView.setText("IP地址："+getIPAddress());
        }
        else if(mActiveNetInfo.getType()==ConnectivityManager.TYPE_MOBILE)  {
            nameTextView.setText("網路型別：3G/4G");
            ipTextView.setText("IP地址："+getIPAddress());
        }
        else  {
            nameTextView.setText("網路型別：未知");
            ipTextView.setText("IP地址：");
        }
    }

    private void myDialog()  {
        AlertDialog mDialog = new AlertDialog.Builder(MainActivity.this)
                .setTitle("注意")
                .setMessage("當前網路不可用，請檢查網路！")
                .setPositiveButton("確定", new DialogInterface.OnClickListener()  {
                    @Override
                    public void onClick(DialogInterface dialog, int which)  {
                        dialog.dismiss();
                        MainActivity.this.finish();
                    }
                })
                .create();//創建這個對話框
        mDialog.show();//顯示這個對話框
    }
}

3.在AndroidManifest.xml檔案里添置二個權限：

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

4.測驗結果
3G/4G網路、wifi網路、無網路三種情況測驗如下圖：