《Pro Android Graphics》讀書筆記之第五節

標籤：des   android   style   class   blog   c   

Android DIP: Device-independent Pixel Graphics DesignHow Android Supports Device Displays: UI Design and UX Device Display Concepts: Size, Density, Orientation, DIP size Typesmall，normal，large，extra large，extra extra largescreen density

the number of physical pixels contained in a one inch area of a given device’s display screen

density type

low or LDPI, medium or MDPI, tv or TVDPI, high or HDPI, extra high or XHDPI and XXHDPI

Density Independence: Creating Similar User Experiences Android Multi-Screen Support Via <supports-screens> Tag

in manifest：<supports-screens android:largeScreens="true" android:xlargeScreens="true" />

Providing Device-Optimized User Interface Layout Designs Using Android’s SmallestWidth Screen Configuration Modifiertakes the format sw#dp 

使用這個格式，進行螢幕判斷，使用不同xml檔案。

720 DIP, then you would use this qualifier to create the layout resource folder named /res/layout-sw720dp to hold your user interface layout definition XML files for your app’s Activities

Using the Available Screen Width Screen Configuration Modifier

w#dp (example: w480dp)：橫豎屏 切換 使用不同布局（根據可視寬度）

不用同時關注方向和螢幕大小：This is due to the fact that even on the larger tablet devices, you often don’t want to use the same multiple pane UI layout design for the portrait orientation as you do for the landscape orientation. With the width screen configuration modifier, you can use something like w640dp to specify a 640 DIP minimum available screen area width for your layout, instead of having to implement both the screen size qualifier and orientation qualifier.

Using the Available Screen Height Screen Configuration Modifier

h#dp (example: h600dp)

Providing Device-Optimized Image Drawable Assets 資源匹配過程

no density-matching assets can be located in your /res/drawable folders, Android will use your default assets, which are kept in the /res/drawable folder; if none are found there, Android will use the MDPI density resources in the /res/drawable-mdpi folder, and will then scale these up or down as needed to match the current screen size and density.

作者經驗

I keep only XML definitions for things like animations and transitions in this /res/drawable folder, and then keep all of my pixel-based digital imaging assets in those various density-specific /res/drawable-dpi folders. 

本檔案夾沒有，去別的檔案夾找，然後按比例縮放。res/drawable-nodpi

no scale 

/res/drawable-land-hdpi would contain landscape HDPI assets

The DisplayMetrics Class: Size, Density, and Font Scaling

package : android.util

display physical size in both the X and Y dimensions

DisplayMetrics currentDeviceDisplayMetrics = new DisplayMetrics();getWindowManager().getDefaultDisplay().getMetrics(currentDeviceDisplayMetrics);

DisplayMetrics : 參數

Optimizing Android Application Icons for LDPI to XXXHDPI Installing the New App Icon in the Correct Density Folders Configuring the AndroidManifest.xml for Custom App Icon