网络判断

public class Utils {


    /*
     * 判断网络连接是否已开
     * true 已打开  false 未打开
     * */
    public static boolean isConn(Context context) {
        boolean bisConnFlag = false;
        ConnectivityManager conManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo network = conManager.getActiveNetworkInfo();
        if (network != null) {
            bisConnFlag = conManager.getActiveNetworkInfo().isAvailable();
        }
        return bisConnFlag;
    }


    /**
     *      * 当判断当前手机没有网络时选择是否打开网络设置
     *      * @param context
     *      
     */
    public static void showNoNetWorkDlg(final Context context) {
        AlertDialog.Builder builder = new AlertDialog.Builder(context);
        builder.setIcon(R.mipmap.ic_launcher)//
                .setTitle(R.string.app_name)//
                .setMessage("当前无网络").setPositiveButton("设置", new DialogInterface.OnClickListener() {


            @Override
            public void onClick(DialogInterface dialog, int which) {
// 跳转到系统的网络设置界面
                Intent intent = null;
// 先判断当前系统版本
                if (android.os.Build.VERSION.SDK_INT > 10) { // 3.0以上
                    intent = new Intent(android.provider.Settings.ACTION_WIRELESS_SETTINGS);
                } else {
                    intent = new Intent();
                    intent.setClassName("com.android.settings", "com.android.settings.WirelessSettings");
                }
                context.startActivity(intent);


            }
        }).setNegativeButton("知道了", null).show();
    }


}
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public class MainActivity extends AppCompatActivity {


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        boolean conn = Utils.isConn(this);
        if (conn) {
            Toast.makeText(this, "有网络", Toast.LENGTH_LONG).show();
        } else {
           Toast.makeText(this, "无网络", Toast.LENGTH_LONG).show();
        }


    }
}