ConnectivityManager conn = (ConnectivityManager) getSystemService(Activity.CONNECTIVITY_SERVICE);

boolean wifi = conn.getNetworkInfo(ConnectivityManager.TYPE_WIFI).isConnectedOrConnecting();

boolean internet = conn.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).isConnectedOrConnecting();

if (wifi | internet) {

     Toast.makeText(getApplicationContext(), "网络已连接", Toast.LENGTH_LONG).show();

} else {

     Toast.makeText(getApplicationContext(), "未连接网络。", Toast.LENGTH_LONG).show();

}                

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

    ConnectivityManager manager;

    /*检测网络是否连接*/

    private boolean checkNetworkState() {

        boolean flag = false;

        //得到网络连接信息

        manager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);

        //去进行判断网络是否连接

        if (manager.getActiveNetworkInfo() != null) {

            flag = manager.getActiveNetworkInfo().isAvailable();

        }

        if (!flag) {

            setNetwork();//设置网络

        } else {

            isNetworkAvailable();//判断连接方式

        }

        return flag;

    }

    /* 网络已连接，判断连接方式 */

    private void isNetworkAvailable() {

        State gprs = manager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).getState();

        State wifi = manager.getNetworkInfo(ConnectivityManager.TYPE_WIFI).getState();

        if (gprs == State.CONNECTED || gprs == State.CONNECTING) {

            Toast.makeText(this, "网络已连接！连接方式：gprs", Toast.LENGTH_SHORT).show();

        }

        if (wifi == State.CONNECTED || wifi == State.CONNECTING) {

            Toast.makeText(this, "网络已连接！连接方式：wifi", Toast.LENGTH_SHORT).show();

            // do something: wifi状态下才能做某事

        }

    }

    /* 网络未连接，调用设置方法 */

    private void setNetwork() {

        Toast.makeText(this, "网络未连接。", Toast.LENGTH_SHORT).show();

        AlertDialog.Builder builder = new AlertDialog.Builder(this);

        builder.setIcon(R.drawable.ic_launcher);

        builder.setTitle("网络提示信息");

        builder.setMessage("网络不可用，如果继续，请先设置网络！");

        builder.setPositiveButton("设置", new OnClickListener() {

            @Override

            public void onClick(DialogInterface dialog, int which) {

                Intent intent = null;

                /*

                 * 判断手机系统，如果API>10 就是3.0+ 3.0以上和3.0以上设置不一样， 调用的方法不一样

                 */

                if (android.os.Build.VERSION.SDK_INT > ) {

                    intent = new Intent(android.provider.Settings.ACTION_WIFI_SETTINGS);

                } else {

                    intent = new Intent();

                    ComponentName component = new ComponentName("com.android.settings",

                            "com.android.settings.WirelessSettings");

                    intent.setComponent(component);

                    intent.setAction("android.intent.action.VIEW");

                }

                startActivity(intent);

            }

        });

        builder.setNegativeButton("取消", new OnClickListener() {

            @Override

            public void onClick(DialogInterface dialog, int which) {

            }

        });

        builder.create();

        builder.show();

    }