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This article shows you how to create Android applications that support different screen sizes. The content is concise and easy to understand. I hope you can learn something from the detailed introduction of this article.

Supporting Different Screens

Android classifies device screens with two general attributes: size and pixel density. As a developer, you should expect that your android application will be installed on devices with different screen sizes and pixel densities. Therefore, your application should include optional resources to optimize the appearance of the application to support devices of the above different sizes and pixel densities.

* there are four broad sizes: small, normal, large, xlarge.

* there are also four broad pixel densities: low (ldpi), medium (mdpi), high (hdpi), and extra high (xhdpi).

In order to declare different layouts layouts and bitmaps resources for different screens, you must put these optional resource files in different directories, similar to what you do with strings in different languages when internationalizing.

At the same time, note that the screen orientation (landscape or portrait) is also considered to be a change in screen size, so most applications should modify the layout layout to improve the user experience in different screen directions.

Create different Layout layout files-Create Different Layouts

To improve the user experience on different device screens, you should create a unique XML layout file for each screen size you want to support. Each layout file should be stored in the appropriate resource directory with the screen size-as a suffix. For example, a layout file for a large screen should be placed under the res/layout-large/ directory.

Note: Android will automatically scale your layout to fit the screen. In this way, layout files used for different screens do not have to think too much about the absolute size of the UI elements, but should instead focus on the structure of the layout, which will directly affect the user experience (for example, the size or location of important view views should be relative to the sibling view views).

For example, the following project contains a default layout and an optional layout directory for the big screen:

MyProject/ res/ layout/ main.xml layout-large/ main.xml

The layout file names in the directory must be consistent, but their contents can be different to provide optimized UI to support the corresponding screen size.

Simply get a reference to the layout layout file in app as usual:

@ Override protected void onCreate (Bundle savedInstanceState) {super.onCreate (savedInstanceState); setContentView (R.layout.main);}

The Android system will load the layout file from the appropriate layout directory according to the screen size of the device on which your app application is running. More information on how the Android system selects the appropriate resource files can be found in the Providing Resources | Resource provision-Providing Resources guide.

Here is another example in which an optional landscape layout is used to support landscape screens:

MyProject/ res/ layout/ main.xml layout-land/ main.xml

By default, layout/main.xml files are laid out vertically.

If you want to provide a special horizontal layout, such as supporting a large screen, you need to use both large and land to decorate it.

MyProject/ res/ layout/ # default (portrait) main.xml layout-land/ # landscape main.xml layout-large/ # large (portrait) main.xml layout-large-land/ # large landscape main.xml

Note: * Android 3.2 and above supports a better way to define screen size, which allows us to specify resources for different screens through minimum width and height in the case of density-independent pixels. We do not cover this new feature in this section. For more information, please read Designing for Multiple Screens | Multi-screen adaptation Design-Designing for Multiple Screens

Create different Bitmaps resources-Create Different Bitmaps

You should provide appropriate bitmap resources that have been scaled for each of all generalized pixel densities: low low, medium medium, high high, and ultra-high extra-high pixel density. This will enable your application to achieve excellent graphics quality and rendering on all resolution devices.

In order to generate these image resources, you should create the original image resources in vector format, and then generate pictures of each resolution according to the following zoom size:

Extra high resolution xhdpi: 2.0

High resolution hdpi: 1.5

Medium resolution mdpi: 1. 0 (benchmark)

Low resolution ldpi: 0.75

This means that if you want to generate a 200x200 image for an ultra-high resolution device, you need to generate 150x150 for a high-resolution device, 100x100 for a medium-resolution device, and 100x100 for a low-resolution device.

A picture of 75x75.

Then place these files in the appropriate resource directory:

MyProject/ res/ drawable-xhdpi/ awesomeimage.png drawable-hdpi/ awesomeimage.png drawable-mdpi/ awesomeimage.png drawable-ldpi/ awesomeimage.png

In the future, when you quote @ drawable/awesomeimage, the system will automatically select the appropriate image resource according to the resolution of the device.

Note: low resolution (ldpi) resources are not always required. When you provide high-resolution resources, the system will scale them in half to fit the low-resolution device.

For more tips and design guidance on creating application icons, see Iconography design guide | Icon Design Guide-Iconography design guide.

The above content is how to create Android applications that support different screen sizes. Have you learned the knowledge or skills? If you want to learn more skills or enrich your knowledge reserve, you are welcome to follow the industry information channel.

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