How to use UsageStatsManager?

问题

Background

Google has deprecated the function "getRecentTasks" of "ActivityManager" class. Now all it does is to get the list of apps that the current app has opened.

I've even written a post about it here on StackOverflow, but I noticed it's impossible.

The problem

I've made a post about it (here, and another, similar one created by someone else, here) and requested to re-consider it, and Google decided to make a new class, that seem to provide a similar functionality (more like statistics, but might also be useful), but I can't find out how to use it.

The class is called "UsageStatsManager", and my guess is that the function "queryUsageStats" does the job.

Also, it seems it has a new permission ("android.permission.PACKAGE_USAGE_STATS"), which is a system permission, but it's written that:

declaring the permission implies intention to use the API and the user of the device can grant permission through the Settings application.

Here's another link about this new functionality.

What I've found

I've looked at the code of Android, and noticed that "Context" has USAGE_STATS_SERVICE , which in the JavaDocs say the next thing:

/**
 * Use with {@link #getSystemService} to retrieve a {@link
 * android.app.UsageStatsManager} for interacting with the status bar.
 *
 * @see #getSystemService
 * @see android.app.UsageStatsManager
 * @hide
 */
public static final String USAGE_STATS_SERVICE = "usagestats";

The weird thing is that not only it says "status bar", but also the packageName doesn't match (should be "android.app.usage.UsageStatsManager" instead) .

I've also added the correct permission:

<uses-permission
    android:name="android.permission.PACKAGE_USAGE_STATS"
    tools:ignore="ProtectedPermissions" />

and here's the code I use:

  final UsageStatsManager usageStatsManager=(UsageStatsManager)context.getSystemService("usagestats");// Context.USAGE_STATS_SERVICE);
  final int currentYear=Calendar.getInstance().get(Calendar.YEAR);
  final List<UsageStats> queryUsageStats=usageStatsManager.queryUsageStats(UsageStatsManager.INTERVAL_YEARLY,currentYear-2,currentYear);

In the emulator itself, I went to "Settings"->"security"->"apps with usage access" , and enabled my app.

However, when running the code, all I get is an empty list...

The question

How do you use UsageStatsManager ?

Also, how do you let the user to grant the permission in the easiest way possible? Or is it automatically done, as soon as the app tries to get the needed information?

What happens when trying to use this class yet the user hasn't confirmed it yet?

How can I make the code return me a real list of apps?

回答1:

I think the documentation was just short hand for the Calendar stuff. I don't think it actually works with just 2014; however I can be wrong.

In order to access the actually list of UsageStats, you would need to create a Calendar object with the correct month,day, and year. Exactly how MRK said in the other answer. I copied and corrected the errors in MRK's code so anyone who sees it in the future can see it.

Calendar beginCal = Calendar.getInstance();
beginCal.set(Calendar.DATE, 1);
beginCal.set(Calendar.MONTH, 0);
beginCal.set(Calendar.YEAR, 2012);

Calendar endCal = Calendar.getInstance();
endCal.set(Calendar.DATE, 1);
endCal.set(Calendar.MONTH, 0);
endCal.set(Calendar.YEAR, 2014);

final List<UsageStats> queryUsageStats=usageStatsManager.queryUsageStats(UsageStatsManager.INTERVAL_YEARLY, beginCal.getTimeInMillis(), endCal.getTimeInMillis());

-Credit MRK; corrected by me (he accidentally just put cal instead of beginCal and endCal)

The code for the usage access settings is below. :)

Intent intent = new Intent(Settings.ACTION_USAGE_ACCESS_SETTINGS);
startActivity(intent);

回答2:

I've created a sample of how to use UsageStats on my Github. Hopefully it can be of help to someone

https://github.com/ColeMurray/UsageStatsSample

回答3:

Answering your last question "How can I make the code return me a real list of apps?". queryUsageStats takes begin time and end time in milliseconds, not the value of the year in int.

Calendar beginCal = Calendar.getInstance();
beginCal.set(Calendar.DATE, 1);
beginCal.set(Calendar.MONTH, 0);
beginCal.set(Calendar.YEAR, 2012);

Calendar endCal = Calendar.getInstance();
endCal.set(Calendar.DATE, 1);
endCal.set(Calendar.MONTH, 0);
endCal.set(Calendar.YEAR, 2014);

final List<UsageStats> queryUsageStats=usageStatsManager.queryUsageStats(UsageStatsManager.INTERVAL_YEARLY, beginCal.getTimeInMillis(), endCal.getTimeInMillis());

This should return a list of UsageStats for the years 2012 and 2013 (keep in mind the end time is exclusive of the end result time range).

回答4:

Use UsageStats will get the wrong information when user opens the notification drawer or on a locked screen. You have to use UsageStatsManager.queryEvents() and look for the latest event with MOVE_TO_FOREGROUND event type.

回答5:

There is actually an example app included in AOSP sample code: developers/samples/android/system/AppUsageStatistics/

It includes all the bits necessary to use UsageStats in an app:

1. Declaring the permission in AndroidManifest.xml

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

2. Show settings to grant permission to access UsageStatsManager

   startActivity(new Intent(Settings.ACTION_USAGE_ACCESS_SETTINGS));

3. Query UsageStatsManager for statistics.

   Calendar cal = Calendar.getInstance();
   cal.add(Calendar.YEAR, -1);
   List<UsageStats> queryUsageStats = mUsageStatsManager
           .queryUsageStats(intervalType, cal.getTimeInMillis(),
                   System.currentTimeMillis());
   

4. Creating a list of apps based on UsageStats

To summarize and apply to your example:

• You seem to correctly ask for and grant permissions to access usage stats.
• You correctly get the UsageStats system service.
• However, the time period you query for is way to short: Arguments beginTime and endTime are measured in milliseconds since the epoch. Calendar instances can give you this value with getTimeinMillis(). What you erroneously do is to only give the year numbers (2015 and2017 if you would run the program today). These values are interpreted as milliseconds since the epoch and thus the interval is only 2 milliseconds long and is some time in 1970.

Instead of the following code snippet that you posted, you should copy the example I posted below:

Wrong:

final int currentYear=Calendar.getInstance().get(Calendar.YEAR);
final List<UsageStats> queryUsageStats=usageStatsManager.queryUsageStats(UsageStatsManager.INTERVAL_YEARLY,currentYear-2,currentYear);

Correct:

final long currentTime = System.currentTimeMillis(); // Get current time in milliseconds

final Calendar cal = Calendar.getInstance();
cal.add(Calendar.YEAR, -2); // Set year to beginning of desired period.
final long beginTime = cal.getTimeInMillis(); // Get begin time in milliseconds

final List<UsageStats> queryUsageStats=usageStatsManager.queryUsageStats(UsageStatsManager.INTERVAL_YEARLY, beginTime, currentTime);

回答6:

If you want to see usage statistics of a specific time period. You have to first calculate the length of time in milliseconds of the start and end of your time period, since the epoch. (epoch is the number of seconds that have elapsed since 00:00:00 UTC, Thursday 1, 1970.) Or, as I will show in the following sample code, an easy way is to calculate backwards from the current time in milliseconds.

For example, if you want stat of the past 4 days, it would be:

UsageStatsManager mUsageStatsManager = (UsageStatsManager) this.getSystemService(Context.USAGE_STATS_SERVICE);    
List<UsageStats> queryUsageStats = mUsageStatsManager.queryUsageStats(UsageStatsManager.INTERVAL_DAILY,
                    (System.currentTimeMillis() - 345600000), System.currentTimeMillis());

The number 345600000 is the amount of milliseconds of 4 days.

And for the INTERVAL_TYPE this explains it well.

The system collects and aggregates the data over 4 different intervals and they are: INTERVAL_DAILY, INTERVAL_WEEKLY, INTERVAL_MONTHLY and INTERVAL_YEARLY. The system records are limited in time, so you’ll be able to retrieve app usage data for up to 7 days for interval daily, up to 4 weeks for interval weekly, up to 6 months for monthly and finally up to 2 years for yearly. There’s a fifth option to mention: INTERVAL_BEST will choose the best fitting interval between the four above based on the timespan you’ve chosen.

回答7:

you can do like this

//noinspection ResourceType
final UsageStatsManager usageStatsManager=(UsageStatsManager)context.getSystemService("usagestats");// Context.USAGE_STATS_SERVICE);
final int currentYear=Calendar.getInstance().get(Calendar.YEAR);
final List<UsageStats> queryUsageStats=usageStatsManager.queryUsageStats(UsageStatsManager.INTERVAL_YEARLY,currentYear-2,currentYear);

来源：https://stackoverflow.com/questions/26431795/how-to-use-usagestatsmanager