我想在我的项目中实现一个时间表功能。所以我在谷歌上搜索了一个警报管理程序，但我找不到任何例子。
谁能帮我一个基本的警报管理程序?
当前回答
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。
其他回答
•AlarmManager与IntentService结合使用
我认为使用AlarmManager的最佳模式是它与IntentService的协作。IntentService由AlarmManager触发，它通过接收意图处理所需的操作。这种结构不像使用BroadcastReceiver那样对性能有影响。我在kotlin中为这个想法开发了一个示例代码，可以在这里获得:
MyAlarmManager.kt
import android.app.AlarmManager
import android.app.PendingIntent
import android.content.Context
import android.content.Intent
object MyAlarmManager {
private var pendingIntent: PendingIntent? = null
fun setAlarm(context: Context, alarmTime: Long, message: String) {
val alarmManager: AlarmManager = context.getSystemService(Context.ALARM_SERVICE) as AlarmManager
val intent = Intent(context, MyIntentService::class.java)
intent.action = MyIntentService.ACTION_SEND_TEST_MESSAGE
intent.putExtra(MyIntentService.EXTRA_MESSAGE, message)
pendingIntent = PendingIntent.getService(context, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT)
alarmManager.set(AlarmManager.RTC_WAKEUP, alarmTime, pendingIntent)
}
fun cancelAlarm(context: Context) {
pendingIntent?.let {
val alarmManager: AlarmManager = context.getSystemService(Context.ALARM_SERVICE) as AlarmManager
alarmManager.cancel(it)
}
}
}
MyIntentService.kt
import android.app.IntentService
import android.content.Intent
class MyIntentService : IntentService("MyIntentService") {
override fun onHandleIntent(intent: Intent?) {
intent?.apply {
when (intent.action) {
ACTION_SEND_TEST_MESSAGE -> {
val message = getStringExtra(EXTRA_MESSAGE)
println(message)
}
}
}
}
companion object {
const val ACTION_SEND_TEST_MESSAGE = "ACTION_SEND_TEST_MESSAGE"
const val EXTRA_MESSAGE = "EXTRA_MESSAGE"
}
}
manifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.aminography.alarm">
<application
... >
<service
android:name="path.to.MyIntentService"
android:enabled="true"
android:stopWithTask="false" />
</application>
</manifest>
用法:
val calendar = Calendar.getInstance()
calendar.add(Calendar.SECOND, 10)
MyAlarmManager.setAlarm(applicationContext, calendar.timeInMillis, "Test Message!")
如果你想取消预定的闹钟，试试这个:
MyAlarmManager.cancelAlarm(applicationContext)
下面是一个使用Kotlin的Alarm Manager的例子:
class MainActivity : AppCompatActivity() {
val editText: EditText by bindView(R.id.edit_text)
val timePicker: TimePicker by bindView(R.id.time_picker)
val buttonSet: Button by bindView(R.id.button_set)
val buttonCancel: Button by bindView(R.id.button_cancel)
val relativeLayout: RelativeLayout by bindView(R.id.activity_main)
var notificationId = 0
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
timePicker.setIs24HourView(true)
val alarmManager = getSystemService(Context.ALARM_SERVICE) as AlarmManager
buttonSet.setOnClickListener {
if (editText.text.isBlank()) {
Toast.makeText(applicationContext, "Title is Required!!", Toast.LENGTH_SHORT).show()
return@setOnClickListener
}
alarmManager.set(
AlarmManager.RTC_WAKEUP,
Calendar.getInstance().apply {
set(Calendar.HOUR_OF_DAY, timePicker.hour)
set(Calendar.MINUTE, timePicker.minute)
set(Calendar.SECOND, 0)
}.timeInMillis,
PendingIntent.getBroadcast(
applicationContext,
0,
Intent(applicationContext, AlarmBroadcastReceiver::class.java).apply {
putExtra("notificationId", ++notificationId)
putExtra("reminder", editText.text)
},
PendingIntent.FLAG_CANCEL_CURRENT
)
)
Toast.makeText(applicationContext, "SET!! ${editText.text}", Toast.LENGTH_SHORT).show()
reset()
}
buttonCancel.setOnClickListener {
alarmManager.cancel(
PendingIntent.getBroadcast(
applicationContext, 0, Intent(applicationContext, AlarmBroadcastReceiver::class.java), 0))
Toast.makeText(applicationContext, "CANCEL!!", Toast.LENGTH_SHORT).show()
}
}
override fun onTouchEvent(event: MotionEvent?): Boolean {
(getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager)
.hideSoftInputFromWindow(relativeLayout.windowToken, InputMethodManager.HIDE_NOT_ALWAYS)
relativeLayout.requestFocus()
return super.onTouchEvent(event)
}
override fun onResume() {
super.onResume()
reset()
}
private fun reset() {
timePicker.apply {
val now = Calendar.getInstance()
hour = now.get(Calendar.HOUR_OF_DAY)
minute = now.get(Calendar.MINUTE)
}
editText.setText("")
}
}
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>
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
我已经用最简单的方式实现了这一点。
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import junit.framework.Assert;
/**
* Created by Daniel on 28/08/2016.
*/
public abstract class AbstractSystemServiceTask {
private final Context context;
private final AlarmManager alarmManager;
private final BroadcastReceiver broadcastReceiver;
private final PendingIntent pendingIntent;
public AbstractSystemServiceTask(final Context context, final String id, final long time, final AlarmType alarmType, final BackgroundTaskListener backgroundTaskListener) {
Assert.assertNotNull("ApplicationContext can't be null", context);
Assert.assertNotNull("ID can't be null", id);
this.context = context;
this.alarmManager = (AlarmManager) this.context.getSystemService(Context.ALARM_SERVICE);
this.context.registerReceiver(
this.broadcastReceiver = this.getBroadcastReceiver(backgroundTaskListener),
new IntentFilter(id));
this.configAlarmManager(
this.pendingIntent = PendingIntent.getBroadcast(this.context, 0, new Intent(id), 0),
time,
alarmType);
}
public void stop() {
this.alarmManager.cancel(this.pendingIntent);
this.context.unregisterReceiver(this.broadcastReceiver);
}
private BroadcastReceiver getBroadcastReceiver(final BackgroundTaskListener backgroundTaskListener) {
Assert.assertNotNull("BackgroundTaskListener can't be null.", backgroundTaskListener);
return new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
backgroundTaskListener.perform(context, intent);
}
};
}
private void configAlarmManager(final PendingIntent pendingIntent, final long time, final AlarmType alarmType) {
long ensurePositiveTime = Math.max(time, 0L);
switch (alarmType) {
case REPEAT:
this.alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(), ensurePositiveTime, pendingIntent);
break;
case ONE_TIME:
default:
this.alarmManager.set(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + ensurePositiveTime, pendingIntent);
}
}
public interface BackgroundTaskListener {
void perform(Context context, Intent intent);
}
public enum AlarmType {
REPEAT, ONE_TIME;
}
}
唯一的下一步就是执行它。
import android.content.Context;
import android.content.Intent;
import android.util.Log;
import ...AbstractSystemServiceTask;
import java.util.concurrent.TimeUnit;
/**
* Created by Daniel on 28/08/2016.
*/
public class UpdateInfoSystemServiceTask extends AbstractSystemServiceTask {
private final static String ID = "UPDATE_INFO_SYSTEM_SERVICE";
private final static long REPEAT_TIME = TimeUnit.SECONDS.toMillis(10);
private final static AlarmType ALARM_TYPE = AlarmType.REPEAT;
public UpdateInfoSystemServiceTask(Context context) {
super(context, ID, REPEAT_TIME, ALARM_TYPE, new BackgroundTaskListener() {
@Override
public void perform(Context context, Intent intent) {
Log.i("MyAppLog", "-----> UpdateInfoSystemServiceTask");
//DO HERE WHATEVER YOU WANT...
}
});
Log.i("MyAppLog", "UpdateInfoSystemServiceTask started.");
}
}
我喜欢使用这个实现，但另一种可能的好方法是，不要使AbstractSystemServiceTask类抽象，而是通过Builder来构建它。
我希望它能帮助你。
更新 改进了允许同一个BroadCastReceiver上有多个BackgroundTaskListener。
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import junit.framework.Assert;
import java.util.HashSet;
import java.util.Set;
/**
* Created by Daniel on 28/08/2016.
*/
public abstract class AbstractSystemServiceTask {
private final Context context;
private final AlarmManager alarmManager;
private final BroadcastReceiver broadcastReceiver;
private final PendingIntent pendingIntent;
private final Set<BackgroundTaskListener> backgroundTaskListenerSet;
public AbstractSystemServiceTask(final Context context, final String id, final long time, final AlarmType alarmType) {
Assert.assertNotNull("ApplicationContext can't be null", context);
Assert.assertNotNull("ID can't be null", id);
this.backgroundTaskListenerSet = new HashSet<>();
this.context = context;
this.alarmManager = (AlarmManager) this.context.getSystemService(Context.ALARM_SERVICE);
this.context.registerReceiver(
this.broadcastReceiver = this.getBroadcastReceiver(),
new IntentFilter(id));
this.configAlarmManager(
this.pendingIntent = PendingIntent.getBroadcast(this.context, 0, new Intent(id), 0),
time,
alarmType);
}
public synchronized void registerTask(final BackgroundTaskListener backgroundTaskListener) {
Assert.assertNotNull("BackgroundTaskListener can't be null", backgroundTaskListener);
this.backgroundTaskListenerSet.add(backgroundTaskListener);
}
public synchronized void removeTask(final BackgroundTaskListener backgroundTaskListener) {
Assert.assertNotNull("BackgroundTaskListener can't be null", backgroundTaskListener);
this.backgroundTaskListenerSet.remove(backgroundTaskListener);
}
public void stop() {
this.backgroundTaskListenerSet.clear();
this.alarmManager.cancel(this.pendingIntent);
this.context.unregisterReceiver(this.broadcastReceiver);
}
private BroadcastReceiver getBroadcastReceiver() {
return new BroadcastReceiver() {
@Override
public void onReceive(final Context context, final Intent intent) {
for (BackgroundTaskListener backgroundTaskListener : AbstractSystemServiceTask.this.backgroundTaskListenerSet) {
backgroundTaskListener.perform(context, intent);
}
}
};
}
private void configAlarmManager(final PendingIntent pendingIntent, final long time, final AlarmType alarmType) {
long ensurePositiveTime = Math.max(time, 0L);
switch (alarmType) {
case REPEAT:
this.alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(), ensurePositiveTime, pendingIntent);
break;
case ONE_TIME:
default:
this.alarmManager.set(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + ensurePositiveTime, pendingIntent);
}
}
public interface BackgroundTaskListener {
void perform(Context context, Intent intent);
}
public enum AlarmType {
REPEAT, ONE_TIME;
}
}
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