Android O: can we make a clock widget?

Question

There is a clock widget in our app. The widget needs to be updated every minute to display the time right.

In Android O, it is advised to use JobScheduler for background updates. Unfortunately, there are limitations.

The periodic updates of JobService can not be called in less than 15 minutes intervals.
The moment JobService.onStartJob() is unpredictable. We may miss the exact moment to update the minute digit (59th second).

Prior O we used to run a background service with Handler.postDelayed() to update the time in the widget. In O the background service can be terminated by the system.

How would you recommend to implement a clock widget in Android O?

Is this even possible now?

This is a very important question. It should not be downvoted — Carson Holzheimer, Oct 02 '17 at 03:35
Yes I upvoted this because this is important....Most of clock widget using old technique because clock widget is the first generation of apps in Android. Now Google forces developer to take step forward. But without clear guided solution. JobIntentService, JobScheduler, JobDispatcher, ForegroundService via Notification...all these seems overkill for a simple clock widget. — stuckedunderflow, Jan 07 '19 at 16:13

score 10 · Accepted Answer · answered Sep 05 '17 at 15:48

10

Use "TextClock" widget control, it is supported by RemoteView functionality and it updates every minute by it self, no need to use those fancy JobScheduler jobs.

Something like this will do the trick:

<LinearLayout
    android:id="@+id/root"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <TextClock
        android:id="@+id/dateText"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="1"
        android:format12Hour="@string/date_text_format_12h"
        android:format24Hour="@string/date_text_format_24h"
        android:gravity="bottom|center_horizontal"
        android:textColor="@android:color/black"
        android:textSize="@dimen/date_text_size_default"/>

    <TextClock
        android:id="@+id/timeText"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="1"
        android:format12Hour="@string/time_text_format_12h"
        android:format24Hour="@string/time_text_format_24h"
        android:gravity="top|center_horizontal"
        android:textColor="@android:color/black"
        android:textSize="@dimen/time_text_size_default"
        android:textStyle="bold"/>

</LinearLayout>

answered Sep 05 '17 at 15:48

Gordon Freeman

1,117
9
22

1

I wasn't expecting the solution to be so simple. We have even contacted Google developer support a couple of weeks ago. They still have not provided any answer. Thank you so much! – Pavel Sep 12 '17 at 06:24
1

TextClock widget is only available starting API 17. – Pavel Sep 12 '17 at 06:25
4

This solution doesn't work for analog clocks. Does anyone know if analog clocks can be created in Android Oreo? – Carson Holzheimer Nov 19 '17 at 05:08
I would also like to know a solution for analog clocks. – ahomphophone Apr 12 '18 at 21:23
Another problem is that you cannot use different fonts with TextClock. Any other solution besides using TextClock? – a.p. Sep 23 '18 at 08:12
So anyone come up with Analog Clock? – stuckedunderflow Jan 07 '19 at 16:44
In fact Analog Clock will just work fine by using JobIntentService – stuckedunderflow Jan 15 '19 at 05:40

score -5 · Answer 2 · answered Aug 16 '17 at 23:43

-5

It's a widget; it doesn't need to update all the time -- only when it's visible. Why would you want to waste battery keeping track of the current time while your widget isn't running?

When the widget becomes visible, look up the current time and draw that right away. Also, calculate when the top of the next minute is, and post a delayed message or Runnable to a handler that will trigger at that moment. When that message/Runnable executes, update your time display and re-post the message/Runnable for the top of the next minute.

You should also register a receiver for the Intent.ACTION_TIME_CHANGED broadcast that the Alarm Manager sends out when the current time is changed; you need to recalculate your displayed time and when the next update will happen in response to that broadcast.

answered Aug 16 '17 at 23:43

ctate

1,379
10
11

2

So, what event it triggered when widget becomes visible? – Gordon Freeman Sep 05 '17 at 14:57
2

As far as I know there is no way to detect the moment the widget becomes visible. – Pavel Sep 12 '17 at 06:26
I agree. There is no way to know if the widget becomes visible so the above suggestion will not work. I am also looking for a solution to make clock widgets work in Android O. No solution so far. – a.p. May 16 '18 at 12:25
Even ACTION_TIME_CHANGED now exempted from Broadcast – stuckedunderflow Jan 07 '19 at 16:10

Android O: can we make a clock widget?

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