Battery life has always been a huge consideration for mobile devices, and remains of the most limiting factors for their use. Most modern smartphones and tablets have little more than a day or two of battery life, and this number can drop to around 8 hours in situations with heavy use or a lot of data activity. An important part of designing an app for an Android phone is to understand how you can make your app as efficient as it possibly can be. This article is an overview of nine different ways that you can extend your users’ battery life and reduce your app’s battery consumption.
1) Pre-fetch data
Prefetching data is pretty much what it sounds like – you download all the data you’re going to need for a given task or period of time in a single transfer (called a ‘burst’) all over the same connection and all at full capacity. Part of what really sucks up a lot of battery life is a lot of what are called radio transfers – these occur when the device uses its wireless radio to connect to a network. The process of starting the radio itself can take a lot of energy. Using this method front-loads a lot of downloading into a single instance of radio usage, limiting the need to connect again in the future and take more power.
2) Batch connections and transfers
Batched connections have a similar philosophy to prefetching data. Every time the radio is activated, it will stay active for at least 20 seconds, just because of how the technology behind it works. Batching is a process that transfers as much data as possible during each existing transfer session to limit the overall number of sessions that are required. The idea is that, if it’s going to be active for 20 seconds anyway, you might as well make those 20 seconds worthwhile. This method also covers standard practices like only downloading the thumbnails of images in a gallery and then downloading the larger image only if it is selected.
3) Connection reduction
Another energy saving tip is to re-use existing network connections rather than initiating new ones. While this sometimes isn’t possible given the fact that devices are mobile, you can set up an app to preference existing network connections over forming new ones. This method has the added benefit of helping network congestion issues on busy servers by more intelligently reacting to data flows and so forth.
4) Identify problem with the DDMS Network Traffic Tool
The DDMS is the Dalvik Debug Monitor Server, which is an Android tool that tracks applications and their network requests and activity. You can use this monitoring software in order to take a closer look at your data and how it flows. This can be really useful to identify spikes in your data flow or connections that seem to take too long or other things that are reacting or flowing in an inconvenient or inefficient way.
Regular updates depend wildly on the device, the user, the specific ways the device is used, and the apps in play. However, you can use the methods described above, particularly batching and prefetching data to save yourself a lot of battery life by coinciding these updates with other moments of activity, which will reduce the overall battery drain of regular scheduled updates.
6) Cache files locally
Duplicate data is important in a lot of cases, but it can also cause a lot of unnecessary file transfers. Cached files are files that are bundled together in a cache that are accessed all at the same time, such as the images in a gallery. Sometimes, caches are active on the cloud in order to save space on a user’s hard drive or memory, but this also leads to a lot of unnecessary transfer of data as the cache is re-downloaded every single time. You can avoid this by storing the cache locally on the device, which prevents it from being downloaded every time it’s needed.
7) Use this cache HttpURL
Connection Android 4.0 added a feature with the tag HttpURLConnection which enables an HTTP response during caching processes. This tends to limit the bandwidth associated with downloading, and eliminates the need for an open network connection, which can preserve a lot of battery life.
Wi-Fi radio tends to provide greater bandwidth with a much lower battery drain. Making Wi-Fi the preferred choice in data transfers is a great plan and should be done whenever possible. You can set up a lot of automatic processes which will delay or postpone large data transfers until in a region with Wi-Fi, and you can also customize an app’s scanners to detect Wi-Fi better.
Connecting to wireless radio or other high-bandwidth sources is a great way to conserve battery, as we’ve already seen. To capitalize on this, set up your app to pre-fetch and batch data when in range of a high-bandwidth network like a Wi-Fi one, and aggressively download more data less frequently. The design philosophy here is definitely one that supports fewer very large transfers over many smaller transfers, so keep that in mind while developing for maximum battery life on an Android.