Question

我有两个按钮save and set alarm和cancel alarm，这些按钮可以完全按照他们的建议行事。

onCreate声明变量

final Intent alarmintent = new Intent(AlarmActivity.this, AlarmReceiver.class);
final AlarmManager alarmManager = (AlarmManager)getSystemService(Context.ALARM_SERVICE);
final PendingIntent sender1 = PendingIntent.getBroadcast(getApplicationContext(), 2, alarmintent, PendingIntent.FLAG_UPDATE_CURRENT |  Intent.FILL_IN_DATA);

代码内取消按钮onClickListener

boolean alarmUp = (PendingIntent.getBroadcast(AlarmActivity.this, 2,alarmintent,PendingIntent.FLAG_NO_CREATE) == null);

if (alarmUp)
            {

                  new AlertDialog.Builder(AlarmActivity.this)
                  .setTitle("Alert")
                  .setMessage("This alarm will be deleted.")
                  .setPositiveButton("Ok", new DialogInterface.OnClickListener() {

                                    public void onClick(DialogInterface arg0, int arg1) {

                                        alarmManager.cancel(sender1);
                                        sender1.cancel();
                                        Toast.makeText(getApplicationContext(), "Alarm Cancelled.", Toast.LENGTH_LONG).show(); 
                                    }


                                })
                                .create().show();
                                }
                                else
                                {
                                    new AlertDialog.Builder(AlarmActivity.this)
                                    .setTitle("Alert")
                                    .setMessage("Alarm for this is not set yet.")
                                 .setPositiveButton("Ok",null)
                                .create().show();
                                }

保存按钮代码

boolean alarmUp = (PendingIntent.getBroadcast(AlarmActivity.this, 2, 
                             alarmintent, 
                                PendingIntent.FLAG_NO_CREATE) == null);


                        if (alarmUp)
                        {
                            //Log.d("myTag", "Alarm is already active");
                            new AlertDialog.Builder(AlarmActivity.this)
                            .setTitle("Alert")
                            .setMessage("Already an alarm is set for this particular time and day.")
                            .setPositiveButton("OK",null    
                            )

                            .create().show();
                        }
    Calendar c = Calendar.getInstance();
alarmManager.setRepeating(AlarmManager.RTC_WAKEUP,c.getTimeInMillis()+5000,24 * 60 * 60 * 1000, sender1);

当我第一次点击save时显示

a http://www.4shared.com/download/puMWZEvRba/alert1.png

然而，由于我还有cancel，我可以点击它来取消闹钟。所以我点击cancel按钮就会显示

a http://www.4shared.com/download/1UOTyVK0ce/alert2.png

这似乎是正确的。但是当我再次单击save按钮时，它会显示

a http://www.4shared.com/download/puMWZEvRba/alert1.png

这意味着cancel按钮虽然为toast执行了this alarm will be deleted.，却没有做它应该做的事情。这再次意味着alarmManager.cancel(sender1)必定存在问题。

问题

要在代码中修改哪些内容才能使cancel按钮正常工作？

P.S

我引用了许多帖子，例如this，但无法解决我案例中的确切问题。

更新代码

取消按钮

final Intent alarmintent = new Intent(AlarmActivity.this, AlarmReceiver.class);
    final AlarmManager alarmManager = (AlarmManager)getSystemService(Context.ALARM_SERVICE);
    final PendingIntent sender1 = PendingIntent.getBroadcast(getApplicationContext(), 2, alarmintent, PendingIntent.FLAG_UPDATE_CURRENT);
    boolean alarmUp = (PendingIntent.getBroadcast(AlarmActivity.this, 2,alarmintent,PendingIntent.FLAG_NO_CREATE) == null);

if (alarmUp)
            {

                  new AlertDialog.Builder(AlarmActivity.this)
                  .setTitle("Alert")
                  .setMessage("This alarm will be deleted.")
                  .setPositiveButton("Ok", new DialogInterface.OnClickListener() {

                                    public void onClick(DialogInterface arg0, int arg1) {

                                        alarmManager.cancel(sender1);
                                        sender1.cancel();
                                        Toast.makeText(getApplicationContext(), "Alarm Cancelled.", Toast.LENGTH_LONG).show(); 
                                    }


                                })
                                .create().show();
                                }
                                else
                                {
                                    new AlertDialog.Builder(AlarmActivity.this)
                                    .setTitle("Alert")
                                    .setMessage("Alarm for this is not set yet.")
                                 .setPositiveButton("Ok",null)
                                .create().show();
                                }

对于保存按钮

 final Intent alarmintent = new Intent(AlarmActivity.this, AlarmReceiver.class);
                        final AlarmManager alarmManager = (AlarmManager)getSystemService(Context.ALARM_SERVICE);
                        final PendingIntent sender1 = PendingIntent.getBroadcast(getApplicationContext(), 2, alarmintent, PendingIntent.FLAG_UPDATE_CURRENT);

boolean alarmUp = (PendingIntent.getBroadcast(AlarmActivity.this, 2, 
                             alarmintent, 
                                PendingIntent.FLAG_NO_CREATE) == null);


                        if (alarmUp)
                        {
                            //Log.d("myTag", "Alarm is already active");
                            new AlertDialog.Builder(AlarmActivity.this)
                            .setTitle("Alert")
                            .setMessage("Already an alarm is set for this particular time and day.")
                            .setPositiveButton("OK",null    
                            )

                            .create().show();
                        }
    Calendar c = Calendar.getInstance();
alarmManager.setRepeating(AlarmManager.RTC_WAKEUP,c.getTimeInMillis()+5000,24 * 60 * 60 * 1000, sender1);

此结果与之前相同。Cancel按钮似乎不起作用。

解决方案

感谢 @David Wasser 我现在正在使用它。请看他的答案。我也不得不改变

boolean alarmUp = (PendingIntent.getBroadcast(AlarmActivity.this, 2, alarmintent,PendingIntent.FLAG_NO_CREATE) == null)

到

两个街区中都有

boolean alarmUp = (PendingIntent.getBroadcast(AlarmActivity.this, 2, alarmintent,PendingIntent.FLAG_NO_CREATE) != null)。

但正如developer.android.com所说FLAG_NO_CREATE Flag indicating that if the described PendingIntent already exists, then simply return null instead of creating it.我不知道这个问题！

Answer 1

这里有几件事是错误的：

1请勿在{{1}}的通话中使用Intent.FILL_IN_DATA。这是PendingIntent.getBroadcast()标志，而不是Intent标志。它不属于这里。

2当您使用PendingIntent时，如果PendingIntent.FLAG_NO_CREATE尚不存在，则会返回null。在设置PendingIntent的代码中，您已向后与alarmUp进行比较。 注意：请参阅本答案末尾的评论，说明此文档的错误

3在null你正在这样做：

onCreate()

即使您没有使用它设置闹钟，此行也会创建PendingIntent sender1 = PendingIntent.getBroadcast(getApplicationContext(), 2, alarmintent, PendingIntent.FLAG_UPDATE_CURRENT | Intent.FILL_IN_DATA);。稍后，当您使用此代码检查PendingIntent是否存在时：

PendingIntent

boolean alarmUp = (PendingIntent.getBroadcast(AlarmActivity.this, 2, alarmintent, PendingIntent.FLAG_NO_CREATE) == null);始终为alarmUp，因为您已在false中创建了PendingIntent。

注意：当您拨打onCreate()时，会创建PendingIntent，而不会在您设置闹钟时创建。{/ p>

编辑：添加更多代码示例

如前所述，如果您想使用它来确定警报是否已设置，则无法创建PendingIntent.getBroadcast()。您必须首先检查PendingIntent是否存在，然后您可以创建它来设置/取消它。要修复，请执行以下操作：

在取消按钮：

中

PendingIntent

在保存按钮：

final Intent alarmintent = new Intent(AlarmActivity.this, AlarmReceiver.class);
final AlarmManager alarmManager = (AlarmManager)getSystemService(Context.ALARM_SERVICE);
// Determine if the alarm has already been set
boolean alarmUp = (PendingIntent.getBroadcast(AlarmActivity.this, 2,alarmintent,PendingIntent.FLAG_NO_CREATE) != null);
if (alarmUp) {
    final PendingIntent sender1 = PendingIntent.getBroadcast(getApplicationContext(), 2, alarmintent, PendingIntent.FLAG_UPDATE_CURRENT);
    ...

再次编辑以修复与final Intent alarmintent = new Intent(AlarmActivity.this, AlarmReceiver.class); final AlarmManager alarmManager = (AlarmManager)getSystemService(Context.ALARM_SERVICE); // Determine if the alarm has already been set boolean alarmUp = (PendingIntent.getBroadcast(AlarmActivity.this, 2, alarmintent, PendingIntent.FLAG_NO_CREATE) != null); if (alarmUp) { final PendingIntent sender1 = PendingIntent.getBroadcast(getApplicationContext(), 2, alarmintent, PendingIntent.FLAG_UPDATE_CURRENT); ... 的文档差异：

注意：关于PendingIntent.FLAG_NO_CREATE 的Android documentation似乎错了！它说：

表示如果描述的PendingIntent已存在的标志，然后只返回null而不是创建它。

但这是倒退。如果PendingIntent.FLAG_NO_CREATE已存在，此方法将返回PendingIntent。 如果尚不存在，则会返回null 。

我编辑了我的答案，以反映此旗帜的正确操作。

报警“取消”按钮无法正常工作

1 个答案: