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我正在使用通知管理器进行内容下载并显示已完成下载的百分比，但是每次我使用新百分比调用 displaymessage 函数时，它都会创建新通知。我怎样才能只更新通知而不每次都创建新通知？

public void displaymessage(String string) {
String ns = Context.NOTIFICATION_SERVICE;
NotificationManager mNotificationManager = (NotificationManager) getSystemService(ns);
int icon = R.drawable.icon;
CharSequence tickerText = "Shamir Download Service";
long when = System.currentTimeMillis();
Notification notification = new Notification(icon, tickerText, when);
Context context = getApplicationContext();
CharSequence contentTitle = "Downloading Content:";
notification.setLatestEventInfo(context, contentTitle, string, null);
final int HELLO_ID = 2;
mNotificationManager.notify(HELLO_ID, notification);

}
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1 回答 1

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我所做的是将通知存储在类级变量中。也许将您的函数更改为 createDownloadNotification 并使用上面的内容，除了使通知成为整个类都可以访问的变量。

然后有另一个函数（类似于 updateDownloadNotification），它将使用更新的信息在通知上调用 setLatestEventInfo。

另请注意，您需要调用 mNotificationManager.notify(HELLO_ID, notification); 每次更新后，否则什么都不会改变。

---更新---实际上你可以只有1个功能并检查通知是否为空（如果不是，创建它）否则使用你已经拥有的。

例子：

public class YourClass extends Service { //or it may extend Activity

private Notification mNotification = null;

public void displaymessage(String string) {
  String ns = Context.NOTIFICATION_SERVICE;

  NotificationManager mNotificationManager = (NotificationManager) getSystemService(ns);
  int icon = R.drawable.icon;
  CharSequence tickerText = "Shamir Download Service";
  long when = System.currentTimeMillis();
  if (mNotification == null) {
    mNotification = new Notification(icon, tickerText, when);
  }
 //mNotification.when = when;//not sure if you need to update this try it both ways
  Context context = getApplicationContext();
  CharSequence contentTitle = "Downloading Content:";
  notification.setLatestEventInfo(context, contentTitle, string, null);
  final int HELLO_ID = 2;
  mNotificationManager.notify(HELLO_ID, mNotification);

}

我的代码实际上有点不同，因为我要更新的只是每次更新时通知的 iconLevel，所以我不确定每次更改是否需要更新 mNotification.when

试一试，看看并报告。

另外我会用这个函数制作一些变量。如果它是类的私有实例变量，通常你会命名一个变量 mSomething。以下是我的建议：

private Notification mNotification = null;
private NotificationManager mNotificationManager = null;
private static final int HELLO_ID = 2;

public void displaymessage(String string) {
  String ns = Context.NOTIFICATION_SERVICE;
  if (mNotificationmanager == null) {
      mNotificationManager = (NotificationManager) getSystemService(ns);
  }
  int icon = R.drawable.icon;
  CharSequence tickerText = "Shamir Download Service";
  long when = System.currentTimeMillis();
  if (mNotification == null) {
    mNotification = new Notification(icon, tickerText, when);
  }
  //mNotification.when = when;//not sure if you need to update this try it both ways
  Context context = getApplicationContext();      
  notification.setLatestEventInfo(context, contentTitle, string, null);      
  mNotificationManager.notify(HELLO_ID, mNotification);

}
于 2012-02-28T20:29:18.823 回答