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I am new to Android and I just started creating an application. I want to place a back ground image for my app. What is the width and height of the image that I've to use so that it works on all the devices.

Satyam
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2 Answers2

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This touches a couple of different concepts. While both are covered in the rather long and cryptic Supporting Multiple Screens document, let me give a few heads up.

  1. You might need to read the document a few times.

  2. Devices are grouped by pixel density and screen size. Pixel density is one of low (ldpi), medium (mdpi), high (hdpi), and the new extra-high (xhdpi). Screen sizes or small, normal, large, and the new extra-large. Also, there are two orientations: portrait and landscape. If you look at what actually contacts the Android Market, you can ignore everything except mdpi and hdpi for normal screens.

  3. These groupings correspond to separate directories under the res/ directory tree of your project. In res/drawable go all your generic images. In res/drawable-mdpi and res/drawable-hdpi go your images when you have overridden them for the basic types.

  4. Also, these groupings have overlap between "medium density" (about 140 to 180 dpi) and "high density" (about 170 to 250 dpi). For reference, the Motorola Droid X has a 854 pixel by 480 pixel phone in a 4.7" (diagonal) display for a density of 217 dpi.

  5. You generally specify your layout resources in prescaled units (dp for graphics, at 1/160 per inch intervals or sp equivalent in text). See this question for more information.

  6. The different measurements are needlessly confusing. Make a mdpi image at about 640 x 480 and a hdpi image at about 800 x 600 and you should be about right. Also, the aspect ratio is not guaranteed, you may need to use the 9-patch tool to make sure it stretches correctly.

  7. If you really want to see the device resolution, you can ask for the getWindowManager().getDefaultDisplay().getWidth()/.getHeight() number of pixels.

Happy Coding!

Community
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Charles Merriam
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Since android doesn't have any specific resolution. We need this by different drawable folders. Better to refer this link

Labeeb Panampullan
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