所有屏幕的背景图像大小

Question

I want to use background image in my app.But i am so confused about different screen sizes.I found this question:

Android: Background Image Size (in Pixel) which Support All Devices

But in answer he said xxxhdpi: 1280x1920 px but Lg G3 is xxxHdpi and screen resolution: 1440 x 2560

I need a roadmap.How should be my image sizes for all screens ? (mdpi,hdpi,xhdpi etc.)

Answer 1

Android devices' screen sizes in pixels and screen width in inches, can differ significantly from device to device. To address this issue, google lets you use different resources per size/density category See here for some more info.

Generally speaking, you must put the largest size image that you want to support for each dpi in the correct folder, and let android do the resizing.

You can also check the imageView's ScaleType attribute to choose how to scale the image to fit the view.

EDIT

the reason to use the different folders and not just one large image is that the larger the image, the more memory it consumes. For example a 1920x1280 image is nice to have on a 1920 screen, but on a 320pixels screen the extra resolution is wasted and you have a lot of wasted memory used.

Answer 2

An easier way is to include one single image in your drawable directory, then, in the OnCreate function of your activity, create a bitmap to fit the screen and put it in an imageview that has width and height set to "wrap_content".

This should work for any device.

Answer 3

Read this link . In particular, I think what you're looking for is:

To create alternative bitmap drawables for different densities, you should follow the 3:4:6:8:12:16 scaling ratio between the six generalized densities. For example, if you have a bitmap drawable that's 48x48 pixels for medium-density screens, all the different sizes should be:

36x36 (0.75x) for low-density

48x48 (1.0x baseline) for medium-density

72x72 (1.5x) for high-density

96x96 (2.0x) for extra-high-density

180x180 (3.0x) for extra-extra-high-density

192x192 (4.0x) for extra-extra-extra-high-density

and also:

xlarge screens are at least 960dp x 720dp

large screens are at least 640dp x 480dp

normal screens are at least 470dp x 320dp

small screens are at least 426dp x 320dp