Android screen adaptation

This post writes about Android screen adaptation

1, Picture text adaptation

When an Android project is built with the Eclipse development environment, the system generates DRAWABLE-LDPI, DRAWABLE-MDPI, drawable-hdpi, drawable-xhdpi, DRAWABLE-XXHDPI Five versions to accommodate different screens.

File directory	Screen type	Resolution	Dpi	DP|PX Correspondence	Size	Spec icon
drawable-ldpi	QVGA	240*320	120	0.75x	small	36*36
drawable-mdpi	HVGA	320*480	160	1x		48*48
drawable-hdpi	WVGA	480*800	240	1.5x	large	72*72
drawable-xhdpi	720p	720*1280	Span style= "Font-family:microsoft Yahei; font-size:13px; " >320	2x	SD	96*96
drawable-xxhdpi	1080P	1080*1920	480	3X	Hd	144*144

Text conversion: 1SP = 2px; for example, 16sp = 32PX,14SP = 28px

2, some design principles:
1) fill_parent, Wrap_content, Match_parent, and DP should be used to set the control dimensions in the layout file;
Specifically, when setting the values of the view's properties Android:layout_width and Android:layout_height, the Wrap_content,match_parent or DP is better than PX, and the text size should be defined using the SP.

2) do not appear in the code of the program specific pixel values, defined in the Dimens.xml;
To make the code simple, Android internally uses the PIX to represent the size of the control, but this is based on the current screen. To accommodate multiple screens, Android recommends that developers not use specific pixels to represent the size of the control.

3) Use 9-patch PNG image
When using the picture resource, if there is a stretch, because the picture processing reason, will deform, cause the interface shape. The 9-patch PNG image is also a standard PGN image, vacated by a pixel interval around the native PNG image, to identify which parts of the PNG picture can be stretched, which cannot be stretched, the border position on the background, and so on.

3. Different layout
Android phone screen size is different, there are 480x320, 640x360, 800x480 ...
Let application automatically adapt to different screens, just need to create a different layout folder in the Res directory, such as: layout-640x360, layout-800x480 ... All layout files are written to R.java after compilation, and the system uses the appropriate layout according to the size of the screen.

Android phone model, screen resolution too much, it is difficult to take into account all, you can choose some representative model test: Xiaomi, Samsung, Huawei, ZTE ...

Android screen adaptation