自定义通知栏，兼容4.0以下

Android自定义通知栏，在4.0以上版本更改通知了的加载方式，需要兼容4.0上下版本

private static CharSequence TICKERTEXT = "TEST";
private long when;
Notification notification;
NotificationManager mNotificationManager;
Intent notificationIntent;
PendingIntent contentIntent;
Context contextIntent;
Notification.Builder builder;

@SuppressWarnings("deprecation")
private void showMsg(CharSequence contentTitle, CharSequence contentText) {
    try {
        contextIntent = Application.getInstance().getApplicationContext();
        builder = new Notification.Builder(contextIntent);//新建Notification.Builder对象
        notificationIntent = new Intent(contextIntent, TextActivity.class);
        notificationIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED);
        contentIntent = PendingIntent.getActivity(contextIntent, 0, notificationIntent, PendingIntent.FLAG_CANCEL_CURRENT);
        mNotificationManager = (NotificationManager) contextIntent.getSystemService(Context.NOTIFICATION_SERVICE);

        when = System.currentTimeMillis();

        builder.setContentTitle(contentTitle);//tiitle
        builder.setContentText(contentText);//文本
        builder.setSmallIcon(R.drawable.app_icon);//icon
        builder.setContentIntent(contentIntent);//跳转
        builder.setTicker(TICKERTEXT);//提示消息
        builder.setWhen(when);//时间
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN)
            notification = builder.build();
        else
            notification = builder.getNotification();
        notification.flags = Notification.FLAG_AUTO_CANCEL;
        notification.defaults = Notification.DEFAULT_SOUND;
        mNotificationManager.notify(1, notification);
    } catch (Exception e) {
        e.printStackTrace();
    }
}