报警经理:

添加到XML布局(*初始化这些视图在创建在主活动)

  <TimePicker
    android:id="@+id/timepicker"
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:layout_weight="2"></TimePicker>

  <Button
    android:id="@+id/btn_start"
    android:text="start Alarm"
    android:onClick="start_alarm_event"
    android:layout_width="match_parent"
    android:layout_height="52dp" />

添加到清单(内部应用程序标签&&外部活动)

 <receiver android:name=".AlarmBroadcastManager"
        android:enabled="true"
        android:exported="true"/>

创建AlarmBroadcastManager类(从BroadcastReceiver继承)

 public class AlarmBroadcastManager extends BroadcastReceiver{
    @Override
    public void onReceive(Context context, Intent intent) {
      MediaPlayer mediaPlayer=MediaPlayer.create(context,Settings.System.DEFAULT_RINGTONE_URI);
      mediaPlayer.start();
    }
 }

在Main Activity中(添加这些功能):

 @RequiresApi(api = Build.VERSION_CODES.M)
 public  void start_alarm_event(View view){
    Calendar calendar=Calendar.getInstance();
    calendar.set(
    calendar.get(Calendar.YEAR),
    calendar.get(Calendar.MONTH),
    calendar.get(Calendar.DAY_OF_MONTH),
    timePicker.getHour(),
    timePicker.getMinute(),
    0
    );
    setAlarm(calendar.getTimeInMillis());
 }

 public void setAlarm(long timeInMillis){
    AlarmManager alarmManager=(AlarmManager) getSystemService(Context.ALARM_SERVICE);
    Intent intent=new Intent(this,AlarmBroadcastManager.class);
    PendingIntent pendingIntent=PendingIntent.getBroadcast(this,0,intent,0);
     alarmManager.setRepeating(AlarmManager.RTC_WAKEUP,timeInMillis,AlarmManager.INTERVAL_DAY,pendingIntent);
    Toast.makeText(getApplicationContext(),"Alarm is Set",Toast.LENGTH_SHORT).show();


 }

我尝试了XXX的解决方案，虽然它最初确实有效，但在某种程度上它停止了工作。onReceive再也没有被调用。我花了好几个小时想知道那是什么。我开始意识到，出于某种神秘的原因，意图不再被召唤。为了解决这个问题，我发现确实需要在清单中为接收者指定一个操作。例子:

<receiver android:name=".Alarm" android:exported="true">
    <intent-filter>
        <action android:name="mypackage.START_ALARM" >
        </action>
    </intent-filter>
</receiver> 

请注意，名称是“。“Alarm”和周期。在XXX的setAlarm方法中，创建Intent，如下所示:

Intent i = new Intent("mypackage.START_ALARM");

START_ALARM消息可以是您想要的任何消息。我这样命名只是为了演示。

I have not seen receivers defined in the manifest without an intent filter that specifies the action. Creating them the way XXX has specified it seems kind of bogus. By specifying the action name, Android will be forced to create an instance of the BroadcastReceiver using the class that corresponds to the action. If you rely upon context, be aware that Android has several different objects that are ALL called context and may not result in getting your BroadcastReceiver created. Forcing Android to create an instance of your class using only the action message is far better than relying upon some iffy context that may never work.

这里有一个相当独立的例子。5秒后按钮变为红色。

    public void SetAlarm()
    {
        final Button button = buttons[2]; // replace with a button from your own UI
        BroadcastReceiver receiver = new BroadcastReceiver() {
            @Override public void onReceive( Context context, Intent _ )
            {
                button.setBackgroundColor( Color.RED );
                context.unregisterReceiver( this ); // this == BroadcastReceiver, not Activity
            }
        };

        this.registerReceiver( receiver, new IntentFilter("com.blah.blah.somemessage") );

        PendingIntent pintent = PendingIntent.getBroadcast( this, 0, new Intent("com.blah.blah.somemessage"), 0 );
        AlarmManager manager = (AlarmManager)(this.getSystemService( Context.ALARM_SERVICE ));

        // set alarm to fire 5 sec (1000*5) from now (SystemClock.elapsedRealtime())
        manager.set( AlarmManager.ELAPSED_REALTIME_WAKEUP, SystemClock.elapsedRealtime() + 1000*5, pintent );
    }

请记住，即使在应用程序未运行时，AlarmManager也会触发。如果你调用这个函数并点击Home键，等待5秒，然后回到你的应用程序，按钮将变成红色。

我不知道如果你的应用程序根本不在内存中，你会得到什么样的行为，所以要小心你试图保存什么样的状态。

我在Android上也遇到了警报问题。问题是关于打盹模式(https://developer.android.com/training/monitoring-device-state/doze-standby)。例如，当我把闹钟调到一个小时后，它就正常了，但如果我把它调到凌晨4点，它就不工作了。我刚刚发现这是非常简单的，我只是应该使用AlarmManager.setAlarmClock()而不是AlarmManager.set()。

所以我决定在github上创建一个示例应用程序。 https://github.com/carlosabreu/androidalarm

报警经理:

添加到XML布局(*初始化这些视图在创建在主活动)

  <TimePicker
    android:id="@+id/timepicker"
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:layout_weight="2"></TimePicker>

  <Button
    android:id="@+id/btn_start"
    android:text="start Alarm"
    android:onClick="start_alarm_event"
    android:layout_width="match_parent"
    android:layout_height="52dp" />

添加到清单(内部应用程序标签&&外部活动)

 <receiver android:name=".AlarmBroadcastManager"
        android:enabled="true"
        android:exported="true"/>

创建AlarmBroadcastManager类(从BroadcastReceiver继承)

 public class AlarmBroadcastManager extends BroadcastReceiver{
    @Override
    public void onReceive(Context context, Intent intent) {
      MediaPlayer mediaPlayer=MediaPlayer.create(context,Settings.System.DEFAULT_RINGTONE_URI);
      mediaPlayer.start();
    }
 }

在Main Activity中(添加这些功能):

 @RequiresApi(api = Build.VERSION_CODES.M)
 public  void start_alarm_event(View view){
    Calendar calendar=Calendar.getInstance();
    calendar.set(
    calendar.get(Calendar.YEAR),
    calendar.get(Calendar.MONTH),
    calendar.get(Calendar.DAY_OF_MONTH),
    timePicker.getHour(),
    timePicker.getMinute(),
    0
    );
    setAlarm(calendar.getTimeInMillis());
 }

 public void setAlarm(long timeInMillis){
    AlarmManager alarmManager=(AlarmManager) getSystemService(Context.ALARM_SERVICE);
    Intent intent=new Intent(this,AlarmBroadcastManager.class);
    PendingIntent pendingIntent=PendingIntent.getBroadcast(this,0,intent,0);
     alarmManager.setRepeating(AlarmManager.RTC_WAKEUP,timeInMillis,AlarmManager.INTERVAL_DAY,pendingIntent);
    Toast.makeText(getApplicationContext(),"Alarm is Set",Toast.LENGTH_SHORT).show();


 }

MainActivity.java

package com.example.alarmexample;  

import android.app.Activity;  
import android.app.AlarmManager;  
import android.app.PendingIntent;  
import android.content.Intent;  
import android.os.Bundle;  
import android.view.View;  
import android.view.View.OnClickListener;  
import android.widget.Button;  
import android.widget.EditText;  
import android.widget.Toast;  

public class MainActivity extends Activity {  
Button b1;  

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

        startAlert();  

}   public void startAlert() { 
        int timeInSec = 2;

        Intent intent = new Intent(this, MyBroadcastReceiver.class);  
        PendingIntent pendingIntent = PendingIntent.getBroadcast(  
                                      this.getApplicationContext(), 234, intent, 0);  
        AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);  
        alarmManager.set(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + (timeInSec * 1000), pendingIntent);  
        Toast.makeText(this, "Alarm set to after " + i + " seconds",Toast.LENGTH_LONG).show();  
    }  

}

MyBroadcastReceiver.java

package com.example.alarmexample;  

import android.content.BroadcastReceiver;  
import android.content.Context;  
import android.content.Intent;  
import android.media.MediaPlayer;  
import android.widget.Toast;  

public class MyBroadcastReceiver extends BroadcastReceiver {  
    MediaPlayer mp;  
    @Override  
    public void onReceive(Context context, Intent intent) {  
        mp=MediaPlayer.create(context, R.raw.alarm);  
        mp.start();  
        Toast.makeText(context, "Alarm", Toast.LENGTH_LONG).show();  
    }  
}  

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>  
<manifest xmlns:android="http://schemas.android.com/apk/res/android"  
    package="com.example.alarmexample" >  

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


    <application  
        android:allowBackup="true"  
        android:icon="@drawable/ic_launcher"  
        android:label="@string/app_name"  
        android:theme="@style/AppTheme" >  

        <activity  
            android:name="com.example.alarmexample.MainActivity"  
            android:label="@string/app_name" >  
            <intent-filter>  
                <action android:name="android.intent.action.MAIN" />  

                <category android:name="android.intent.category.LAUNCHER" />  
            </intent-filter>  
        </activity>  

        <receiver android:name="MyBroadcastReceiver" >  
        </receiver>  
    </application>  

</manifest>