Android: Boot Complete only works if I launch App Immediately

Question

I'm trying to reset alarms in my app and using a receiver to get onBootCompleted. To see if the intent was received, I'm using a toast. The toast only appears if I immediately open the app. Otherwise, the toast does not appear. I looked at previous questions but almost all of them involve services, which I am not using. I am not sure if that is a part of the problem.

Android Manifest

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

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

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity
        android:configChanges="orientation|screenSize|keyboardHidden"
        android:name=".MainActivity"
        android:label="@string/app_name"
        android:launchMode="singleTop" >
        <meta-data android:name="android.app.searchable"
            android:resource="@xml/searchable" />

        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

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

        <intent-filter>
            <action android:name="android.intent.action.SEARCH" />
        </intent-filter>
</activity>
    <receiver android:name=".AlarmReceiver" >
        <intent-filter>
            <action android:name="android.intent.action.ALARM_SERVICE" />
        </intent-filter>
    </receiver>
    <receiver android:name=".AlarmReset"android:enabled="true" android:exported="true">
        <intent-filter>
            <action android:name="android.intent.action.BOOT_COMPLETED" />
            <category android:name="android.intent.category.DEFAULT" />
        </intent-filter>
    </receiver>

</application>

Receiver Class

public class AlarmReset extends BroadcastReceiver {

@Override
public void onReceive(Context context, Intent intent)
{

    Toast.makeText(context, "Hello! Got message",
            Toast.LENGTH_LONG).show();
//reset alarms etc. No service set.
}

I also tried writing the manifest receiver as

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

Key points I found online were to include permissions (which I did) and to watch out for logging.

What I do not understand is why it works if I immediately (within a few seconds, otherwise the toast does not appear) start my activity but is unsuccessful otherwise. I am considering testing a few possibilities like launching the activity itself through code or using a service like most others have. I am currently testing on Android 4.4 on an actual phone.

Answer 1

Starting with Android 3.1 all applications, upon installation, are placed in a "stopped" state.(This is the same state that the application ends up in after the user force-stops the app from the Settings application.)

While in "stopped" state, the application will not run for any reason, except by a manual launch of an activity. (Meaning no BroadcastReceviers(ACTION_PACKAGE_INSTALLED, BOOT_COMPLETED etc.) will be invoked, regardless of the event for which they have registered, until the user runs the app manually.)

But you can start a serivice for ex-

1) In your element:

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

2) In your element (be sure to use a fully-qualified [or relative] class name for your BroadcastReceiver):

<receiver android:name="com.example.MyBroadcastReceiver">  
    <intent-filter>  
        <action android:name="android.intent.action.BOOT_COMPLETED" />  
    </intent-filter>  
</receiver>

In MyBroadcastReceiver.java:

package com.example;

public class MyBroadcastReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        Intent startServiceIntent = new Intent(context, MyService.class);
        context.startService(startServiceIntent);
    }
}