我正在创建通知警报应用程序并且未创建通知

Question

我创建了这个应用程序，但它没有在选择的时间发送通知请任何人帮助我解决这个问题 xml文件：

  <?xml version="1.0" encoding="utf-8"?>

  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

  xmlns:app="http://schemas.android.com/apk/res-auto"

  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical"
  android:gravity="center_horizontal"
  tools:context=".MainActivity">


<EditText
    android:id="@+id/editText"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="Enter your task"
    android:layout_marginBottom="20dp"/>

<TimePicker
    android:id="@+id/timePicker"
    android:layout_width="300dp"
    android:layout_height="342dp"/>

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:gravity="center_horizontal"
    android:layout_marginTop="30dp">
    <Button
        android:id="@+id/setBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="set"
        android:layout_marginRight="20dp"/>
    <Button
        android:id="@+id/cancelBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="cancel"/>
</LinearLayout>

这是应用程序的 MainActivity 类： 包 com.examble.alarmlast; 导入androidx.appcompat.app.AppCompatActivity；

import android.app.AlarmManager;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TimePicker;
import android.widget.Toast;

import java.util.Calendar;

public class MainActivity extends AppCompatActivity {
private AlarmManager alarmMgr;
private PendingIntent alarmIntent;
Button setbtn;
TimePicker timePicker;

EditText edt;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    setbtn = findViewById(R.id.setBtn);
    edt=findViewById(R.id.editText);
    timePicker=findViewById(R.id.timePicker);
    final int hour = timePicker.getCurrentHour();
    final int minute = timePicker.getCurrentMinute();
    setbtn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            //alarmMgr = (AlarmManager)getSystemService(Context.ALARM_SERVICE);
            AlarmManager alarm = (AlarmManager) getSystemService(ALARM_SERVICE);

            Intent intent = new Intent(MainActivity.this, AlarmReceiver.class);
            intent.putExtra("todo", edt.getText().toString());
            alarmIntent = PendingIntent.getBroadcast(MainActivity.this, 0, intent, 0);

         // Set the alarm to start at 8:30 a.m.
            Calendar calendar = Calendar.getInstance();
            calendar.setTimeInMillis(System.currentTimeMillis());
            calendar.set(Calendar.HOUR_OF_DAY,hour );
            calendar.set(Calendar.MINUTE, minute);

           // setRepeating() lets you specify a precise custom interval--in this case,
       // 20 minutes.
           
            alarm.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), 1000 * 60 * 20, 
       alarmIntent);
            Toast.makeText(MainActivity.this, "Done!", Toast.LENGTH_SHORT).show();
        }
    });

      }


   }

这是应用程序的 AlarmReceiver 类：

 package com.examble.alarmlast;
 import android.app.Notification;
 import android.app.NotificationChannel;
 import android.app.NotificationManager;
 import android.app.PendingIntent;
 import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
 import android.os.Build;

 import androidx.core.app.NotificationCompat;
 import androidx.core.app.NotificationManagerCompat;

 import static androidx.core.content.ContextCompat.getSystemService;

 public class AlarmReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {



    String message = intent.getStringExtra("todo");

    // When notification is tapped, call MainActivity.
    Intent mainIntent = new Intent(context, MainActivity.class);
    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
    PendingIntent contentIntent = PendingIntent.getActivity(context, 0, mainIntent, 0);
    if(Build.VERSION.SDK_INT>=Build.VERSION_CODES.O)
    {
        NotificationChannel notificationChannel = new NotificationChannel("n","n",
                NotificationManager.IMPORTANCE_DEFAULT);
        NotificationManager myNotificationManager =
                (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);

        myNotificationManager.createNotificationChannel(notificationChannel);
    }

    // Prepare notification.
    NotificationCompat.Builder builder = new NotificationCompat.Builder(context,"n")
            .setContentText(message)
            .setContentTitle("It's Time!")
            .setSmallIcon(android.R.drawable.ic_dialog_info)
            .setAutoCancel(true)
            .setContentText(message)
            .setWhen(System.currentTimeMillis())
            .setContentIntent(contentIntent)
            .setPriority(Notification.PRIORITY_MAX)
            .setDefaults(Notification.DEFAULT_ALL);

    // Notify
    NotificationManagerCompat notificationManagerCompat = NotificationManagerCompat.from(context);
    notificationManagerCompat.notify(999,builder.build());
 }
}

AndroidManifast：

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

    <application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

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

</manifest>

Answer 1

接收者不知道何时调用自己。

<receiver android:name=".AlarmReceiver">
        <intent-filter>
            <action android:name="android.intent.action.BOOT_COMPLETED" />
        </intent-filter>
    </receiver>

您需要指定何时调用它。