Resources and Internationalization

Resources are external files (that is, non-code files) that are used by your code and compiled into your application at build time. Android supports a number of different kinds of resource files, including XML, PNG, and JPEG files. The XML files have very different formats depending on what they describe. This document describes what kinds of files are supported, and the syntax or format of each.

Resources are externalized from source code, and XML files are compiled into a binary, fast loading format for efficiency reasons. Strings, likewise, are compressed into a more efficient storage form. It is for these reasons that we have these different resource types in the Android platform.

This is a fairly technically dense document, and together with the Available Resources document, they cover a lot of information about resources. It is not necessary to know this document by heart to use Android, but rather to know that the information is here when you need it.

Introduction

This topic includes a terminology list associated with resources, and a series of examples of using resources in code. For a complete guide to the supported Android resource types, see Available Resources.

The Android resource system keeps track of all non-code assets associated with an application. You use the Resources class to access your application's resources; the Resources instance associated with your application can generally be found through Context.getResources().

An application's resources are compiled into the application binary at build time for you by the build system. To use a resource, you must install it correctly in the source tree and build your application. As part of the build process, symbols for each of the resources are generated that you can use in your source code -- this allows the compiler to verify that your application code matches up with the resources you defined.

The rest of this section is organized as a tutorial on how to use resources in an application.

Creating Resources

Android supports string, bitmap, and many other types of resource. The syntax and format of each, and where they're stored, depends upon the type of object. In general, though, you create resources from three types of files: XML files (everything but bitmaps and raw), bitmap files(for images) and Raw files (anything else, for example sound files, etc.). In fact, there are two different types of XML file as well, those that get compiled as-is into the package, and those that are used to generate resources by aapt. Here is a list of each resource type, the format of the file, a description of the file, and details of any XML files.

You will create and store your resource files under the appropriate subdirectory under the res/ directory in your project. Android has a resource compiler (aapt) that compiles resources according to which subfolder they are in, and the format of the file. Table 1 shows a list of the file types for each resource. See the Available Resources for descriptions of each type of object, the syntax, and the format or syntax of the containing file.

Table 1

Directory	Resource Types
res/anim/	XML files that are compiled into frame by frame animation or tweened animation objects
res/drawable/	.png, .9.png, .jpg files that are compiled into the following Drawable resource subtypes: bitmap files 9-patches (resizable bitmaps) To get a resource of this type, use mContext.getResources().getDrawable(R.drawable.imageId) Note: Image resources placed in here may be automatically optimized with lossless image compression by the aapt tool. For example, a true-color PNG that does not require more than 256 colors may be converted to an 8-bit PNG with a color palette. This will result in an image of equal quality but which requires less memory. So be aware that the image binaries placed in this directory can change during the build. If you plan on reading an image as a bit stream in order to convert it to a bitmap, put your images in the res/raw/ folder instead, where they will not be optimized.
res/layout/	XML files that are compiled into screen layouts (or part of a screen). See Declaring Layout.
res/values/	XML files that can be compiled into many kinds of resource. Note: Unlike the other res/ folders, this one can hold any number of files that hold descriptions of resources to create rather than the resources themselves. The XML element types control where these resources are placed under the R class. While the files can be named anything, these are the typical files in this folder (the convention is to name the file after the type of elements defined within): arrays.xml to define arrays colors.xml to define color drawables and color string values. Use Resources.getDrawable() and Resources.getColor(), respectively, to get these resources. dimens.xml to define dimension value. Use Resources.getDimension() to get these resources. strings.xml to define string values (use either Resources.getString or preferably Resources.getText() to get these resources. getText() will retain any rich text styling which is usually desirable for UI strings. styles.xml to define style objects.
res/xml/	Arbitrary XML files that are compiled and can be read at run time by calling Resources.getXML().
res/raw/	Arbitrary files to copy directly to the device. They are added uncompiled to the compressed file that your application build produces. To use these resources in your application, call Resources.openRawResource() with the resource ID, which is R.raw.somefilename.

Resources are compiled into the final APK file. Android creates a wrapper class, called R, that you can use to refer to these resources in your code. R contains subclasses named according to the path and file name of the source file

Global Resource Notes

• Several resources allow you to define colors. Android accepts color values written in various web-style formats -- a hexadecimal constant in any of the following forms: #RGB, #ARGB, #RRGGBB, #AARRGGBB.
• All color values support setting an alpha channel value, where the first two hexadecimal numbers specify the transparency. Zero in the alpha channel means transparent. The default value is opaque.

몇몇 리소스들은 여러분으로 하여금 컬러를 정의할 수 있게 한다. 안드로이드는 다양한 웹 스타일 포맷들로 작성되는 컬러 값을 수용한다 ? 다음과 같은 임의의 형식의 16진수 상수: #RGB, #ARGB, #RRGGBB, #AARRGGBB가 그것이다.
모든 컬러 값은 알파채널 값 설정을 지원하며, 컬러 값의 첫번째 2개의 16진수는 투명도를 나타낸다. 알파 채널이 0인 것은 투명을 의미한다. 디폴트 값은 불투명이다.

Using Resources

This section describes how to use the resources you've created. It includes the following topics:

• Using resources in code- How to call resources in your code to instantiate them.
• Referring to resources from other resources - You can reference resources from other resources. This lets you reuse common resource values inside resources.
• Supporting Alternate Resources for Alternate Configurations - You can specify different resources to load, depending on the language or display configuration of the host hardware.

코드 안에서 리소스 사용하기 ? 여러분의 코드에서 리소스를 인스턴스화하기 위해 그것을 호출하는 방법.
다른 리소스에서 리소스 레퍼런스 하기 - 여러분은 다른 리소스에서 리소스를 레퍼런스할 수 있다. 이것은 여러분으로 하여금 리소스에서 일반적인 리소스 값을 재사용하는 것을 가능하게 한다.
택일적alternate 설정을 위한 택일적 리소스 지원하기 ? 여러분은 호스트 하드웨어의 언어 또는 디스플레이 설정에 의존해서 다른 리소스가 로드load되도록 지정할 수 있다.

At compile time, Android generates a class named R that contains resource identifiers to all the resources in your program. This class contains several subclasses, one for each type of resource supported by Android, and for which you provided a resource file. Each class contains one or more identifiers for the compiled resources, that you use in your code to load the resource. Here is a small resource file that contains string, layout (screens or parts of screens), and image resources.

Note: the R class is an auto-generated file and is not designed to be edited by hand. It will be automatically re-created as needed when the resources are updated.

package com.android.samples;
public final class R {
    public static final class string {
        public static final int greeting=0x0204000e;
        public static final int start_button_text=0x02040001;
        public static final int submit_button_text=0x02040008;
        public static final int main_screen_title=0x0204000a;
    };
    public static final class layout {
        public static final int start_screen=0x02070000;
        public static final int new_user_pane=0x02070001;
        public static final int select_user_list=0x02070002;

    };
    public static final class drawable {
        public static final int company_logo=0x02020005;
        public static final int smiling_cat=0x02020006;
        public static final int yellow_fade_background=0x02020007;
        public static final int stretch_button_1=0x02020008;

    };
};

Using Resources in Code

Using resources in code is just a matter of knowing the full resource ID and what type of object your resource has been compiled into. Here is the syntax for referring to a resource:

R.resource_type.resource_name

or

android.R.resource_type.resource_name

Where resource_type is the R subclass that holds a specific type of resource. resource_name is the name attribute for resources defined in XML files, or the file name (without the extension) for resources defined by other file types. Each type of resource will be added to a specific R subclass, depending on the type of resource it is; to learn which R subclass hosts your compiled resource type, consult the Available Resources document. Resources compiled by your own application can be referred to without a package name (simply as R.resource_type.resource_name). Android contains a number of standard resources, such as screen styles and button backgrounds. To refer to these in code, you must qualify them with android, as in android.R.drawable.button_background.

Here are some good and bad examples of using compiled resources in code:

// Load a background for the current screen from a drawable resource.
this.getWindow().setBackgroundDrawableResource(R.drawable.my_background_image);

// WRONG Sending a string resource reference into a 
// method that expects a string.
this.getWindow().setTitle(R.string.main_title);

// RIGHT Need to get the title from the Resources wrapper.
this.getWindow().setTitle(Resources.getText(R.string.main_title));

// Load a custom layout for the current screen.
setContentView(R.layout.main_screen);

// Set a slide in animation for a ViewFlipper object.
mFlipper.setInAnimation(AnimationUtils.loadAnimation(this, 
        R.anim.hyperspace_in));

// Set the text on a TextView object.
TextView msgTextView = (TextView)findViewByID(R.id.msg);
msgTextView.setText(R.string.hello_message); 

References to Resources

A value supplied in an attribute (or resource) can also be a reference to a resource. This is often used in layout files to supply strings (so they can be localized) and images (which exist in another file), though a reference can be any resource type including colors and integers.

For example, if we have color resources, we can write a layout file that sets the text color size to be the value contained in one of those resources:

<?xml version="1.0" encoding="utf-8"?>
<EditText id="text"
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent" android:layout_height="fill_parent"
    android:textColor="@color/opaque_red"
    android:text="Hello, World!" />

Note here the use of the '@' prefix to introduce a resource reference -- the text following that is the name of a resource in the form of @[package:]type/name. In this case we didn't need to specify the package because we are referencing a resource in our own package. To reference a system resource, you would need to write:

<?xml version="1.0" encoding="utf-8"?>
<EditText id="text"
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent" android:layout_height="fill_parent"
    android:textColor="@android:color/opaque_red"
    android:text="Hello, World!" />

As another example, you should always use resource references when supplying strings in a layout file so that they can be localized:

<?xml version="1.0" encoding="utf-8"?>
<EditText id="text"
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent" android:layout_height="fill_parent"
    android:textColor="@android:color/opaque_red"
    android:text="@string/hello_world" />

This facility can also be used to create references between resources. For example, we can create new drawable resources that are aliases for existing images:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <drawable id="my_background">@android:drawable/theme2_background</drawable>
</resources>

References to Theme Attributes

Another kind of resource value allows you to reference the value of an attribute in the current theme. This attribute reference can only be used in style resources and XML attributes; it allows you to customize the look of UI elements by changing them to standard variations supplied by the current theme, instead of supplying more concrete values.

As an example, we can use this in our layout to set the text color to one of the standard colors defined in the base system theme:

<?xml version="1.0" encoding="utf-8"?>
<EditText id="text"
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent" android:layout_height="fill_parent"
    android:textColor="?android:textDisabledColor"
    android:text="@string/hello_world" />

Note that this is very similar to a resource reference, except we are using an '?' prefix instead of '@'. When you use this markup, you are supplying the name of an attribute resource that will be looked up in the theme -- because the resource tool knows that an attribute resource is expected, you do not need to explicitly state the type (which would be ?android:attr/android:textDisabledColor).

Other than using this resource identifier to find the value in the theme instead of raw resources, the name syntax is identical to the '@' format: ?[namespace:]type/name with the type here being optional.

Using System Resources

Many resources included with the system are available to applications. All such resources are defined under the class "android.R". For example, you can display the standard application icon in a screen with the following code:

public class MyActivity extends Activity
{
    public void onStart() 
    {
        requestScreenFeatures(FEATURE_BADGE_IMAGE);

        super.onStart();

        setBadgeResource(android.R.drawable.sym_def_app_icon);
    }
}

In a similar way, this code will apply to your screen the standard "green background" visual treatment defined by the system:

public class MyActivity extends Activity
{
    public void onStart() 
    {
        super.onStart();

        setTheme(android.R.style.Theme_Black);
    }
}

Alternate Resources (for alternate languages and configurations)

You can supply different resources for your application to use depending on the UI language or hardware configuration on the device. Note that although you can include different string, layout, and other resources, the SDK does not expose methods to let you specify which alternate resource set to load. Android detects the proper set for the hardware and location, and loads them as appropriate. Users can select alternate language settings using the settings panel on the device.

To include alternate resources, create parallel resource folders with qualifiers appended to the folder names, indicating the configuration it applies to (language, screen orientation, and so on). For example, here is a project that holds one string resource file for English, and another for French:

MyApp/
    res/
        values-en/
            strings.xml
        values-fr/
            strings.xml

Android supports several types of qualifiers, with various values for each. Append these to the end of the resource folder name, separated by dashes. You can add multiple qualifiers to each folder name, but they must appear in the order they are listed here. For example, a folder containing drawable resources for a fully specified configuration would look like this:

MyApp/
    res/
        drawable-en-rUS-large-long-port-mdpi-finger-keysexposed-qwerty-navexposed-dpad-480x320/

More typically, you will only specify a few specific configuration options. You may drop any of the values from the complete list, as long as the remaining values are still in the same order:

MyApp/
    res/
        drawable-en-rUS-finger/
        drawable-port/
        drawable-port-mdpi/
        drawable-qwerty/

Table 2 lists the valid folder-name qualifiers, in order of precedence. Qualifiers that are listed higher in the table take precedence over those listed lower, as described in How Android finds the best matching directory.

Table 2

Qualifier	Values
MCC and MNC	The mobile country code optionally followed by mobile network code from the SIM in the device. For example mcc310 (U.S. on any carrier); mcc310-mnc004 (U.S., Verizon brand); mcc208-mnc00 (France, Orange brand); mcc234-mnc00 (U.K., BT brand). If the device uses a radio connection (GSM phone), the MCC will come from the SIM, and the MNC will come from the network to which the device is attached. You might sometimes use the MCC alone, for example to include country-specific legal resources in your application. If your application specifies resources for a MCC/MNC combination, those resources can only be used if both the MCC and the MNC match.
Language and region	The two letter ISO 639-1 language code optionally followed by a two letter ISO 3166-1-alpha-2 region code (preceded by lowercase "r"). For example fr, en-rUS, fr-rFR, es-rES. The codes are not case-sensitive; the r prefix is used to distinguish the region portion. You cannot specify a region alone, but you can specify a language alone, for example en, fr, es.
Screen dimensions	small, normal, large Specify that the resource is for a particular class of screen. The meanings of these are: Normal screens are based on the traditional Android HVGA medium density screen. A screen is considered to be normal if it is at least this size (independent of density) and not large. Examples of such screens a WQVGA low density, HVGA medium density, WVGA high density. Small screens are based on the space available on a QVGA low density screen. Considering a portrait HVGA display, this has the same available width but less height -- it is 3:4 vs. HVGA's 2:3 aspect ratio. Examples are QVGA low density and VGA high density. Large screens are based on the space available on a VGA medium density screen. Such a screen has significantly more available space in both width and height than an HVGA display. Examples are VGA and WVGA medium density screens.
Wider/taller screens	long, notlong Specify that the resource is for a taller/wider than traditional screen. This is based purely on the aspect ration of the screen: QVGA, HVGA, and VGA are notlong; WQVGA, WVGA, FWVGA are long. Note that long may mean either wide or tall, depending on the current orientation.
Screen orientation	port, land, square Specifies that the resource is for a screen that is tall (port) or wide (land); square is not currently used.
Screen pixel density	ldpi, mdpi, hdpi, nodpi Specifies the screen density the resource is defined for. The medium density of traditional HVGA screens (mdpi) is defined to be approximately 160dpi; low density (ldpi) is 120, and high density (hdpi) is 240. There is thus a 4:3 scaling factor between each density, so a 9x9 bitmap in ldpi would be 12x12 is mdpi and 16x16 in hdpi. The special nodpi density can be used with bitmap resources to prevent them from being scaled at load time to match the device density. When Android selects which resource files to use, it handles screen density differently than the other qualifiers. In step 1 of How Android finds the best matching directory (below), screen density is always considered to be a match. In step 4, if the qualifier being considered is screen density, Android will select the best final match at that point, without any need to move on to step 5. You can also specify explicit densities like 92dpi or 108dpi, but these are not fully supported by the system so should not be used.
Touchscreen type	notouch, stylus, finger
Whether the keyboard is available to the user	keysexposed, keyshidden, keyssoft If your application has specific resources that should only be used with a soft keyboard, use the keyssoft value. If no keyssoft resources are available (only keysexposed and keyshidden) and the device shows a soft keyboard, the system will use keysexposed resources.
Primary text input method	nokeys, qwerty, 12key
Whether the navigation keys are available to the user	navexposed, navhidden If the hardware's navigation keys are currently available to the user, the navexposed resources will be used; if they are not available (such as behind a closed lid), navhidden will be used.
Primary non-touchscreen navigation method	nonav, dpad, trackball, wheel
Screen dimensions	320x240, 640x480, etc. The larger dimension must be specified first. This configuration is deprecated and should not be used; use instead screen dimension, wider/taller screens, and screen orientation described above.
SDK version	The SDK version supported by the device, for example v3. The Android 1.0 SDK is v1, the 1.1 SDK is v2, and the 1.5 SDK is v3.
(Minor version)	(You cannot currently specify minor version. It is always set to 0.)

This list does not include device-specific parameters such as carrier, branding, device/hardware, or manufacturer. Everything that an application needs to know about the device that it is running on is encoded via the resource qualifiers in the table above.

All resource directories, qualified and unqualified, live under the res/ folder. Here are some guidelines on qualified resource directory names:

• You can specify multiple qualifiers, separated by dashes. For example, drawable-en-rUS-land will apply to US-English devices in landscape orientation.
• The qualifiers must be in the order listed in Table 2 above. For example:
  • Correct: values-mcc460-nokeys/
  • Incorrect: values-nokeys-mcc460/
• Values are case-insensitive. The resource compiler converts folder names to lower case before processing to avoid problems in case-insensitive file systems. On case-sensitive file systems, you should keep all names lower-case or at least use a consistent case to protect your future sanity when trying to find a resource file.
• Only one value for each qualifier type is supported. For example, if you want to use exactly the same drawable files for Spain and France, you will need two resource directories, such as drawable-rES/ and drawable-rFR/, containing identical files. You cannot have a directory named drawable-rES-rFR/.
• Qualified directories cannot be nested. For example, you cannot have res/drawable/drawable-en.

여러분은 대쉬(-)에 의해 분리되는 여러 개의 수식어를 지정할 수 있다. 예를 들어 drawable-en-rUS-land는 가로방향 오리엔테이션의 미국(US)-영어(English) 디바이스에 적용될 것이다.
수식어는 위의 테이블 2에서 나열된 순서로 되어야 한다. 예를 들어 다음과 같다.
• 옳음 : values-mcc460-nokeys/
• 틀림 : values-nokeys-mcc460/
값들은 대소문자를 구분하지 않는다. 리소스 컴파일러는 대소문자를 구분하는 파일 시스템에서의 문제를 피하기 위해서 포로세싱 전에에 폴더 이름을 소문자로 변환한다. 대소문자를 구분하는 파일 시스템에서 여러분은 모든 이름을 소문자로 유지하거나, 나중에 리소스 파일을 찾고자 할 때 여러분이 합리적으로 할 수 있도록 적어도 일관된 방식을 사용해야 한다.
각각의 수식어 타입에 대해서는 오직 하나의 값만이 지원된다. 예를 들어 만약 여러분이 스페인과 프랑스을 위해 정확하게 동일한 드로어블drawable 파일을 사용하고자 한다면, 여러분은 똑같은 파일을 포함하고 있는 drawable-rES/ 와 drawable-rFR/ 과 같이 두 개의 리소스 디렉토리를 필요로 할 것이다. 여러분은 drawable-rES-rFR/ 로 명명된 디렉토리를 가질 수 없다.
수식어 디렉토리는 다른 수식어 디렉토리 안에 있을 수 없다cannot be nested. 예를 들어 여러분은 res/drawable/drawable-en 을 가질 수 없다.

How resources are referenced in code

All resources will be referenced in code or resource reference syntax by their simple, undecorated names. So if a resource were named this:
MyApp/res/drawable-port-mdpi/myimage.png
It would be referenced as this:
R.drawable.myimage (code)
@drawable/myimage (XML)

If several drawable directories are available, Android will select one of them (as described below) and load myimage.png from it.

How Android finds the best matching directory

Android will pick which of the various underlying resource files should be used at runtime, depending on the current configuration of the device. The example used here assumes the following device configuration:

Locale = en-GB
Screen orientation = port
Screen pixel density = mdpi
Touchscreen type = notouch
Primary text input method = 12key

Here is how Android makes the selection:

1. Eliminate resource files that contradict the device configuration. For example, assume that the following resource directories are available for drawables. The drawable-fr-rCA/ directory will be eliminated, because it contradicts the locale of the device.
   

   MyApp/res/drawable/
   MyApp/res/drawable-en/
   MyApp/res/drawable-fr-rCA/
   MyApp/res/drawable-en-port/
   MyApp/res/drawable-en-notouch-12key/
   MyApp/res/drawable-port-ldpi/
   MyApp/res/drawable-port-notouch-12key

   Exception: Screen pixel density is the one qualifier that is not used to eliminate files. Even though the screen density of the device is medium dpi, drawable-port-ldpi/ is not eliminated from the list, because every screen density is considered to be a match at this point.
2. From Table 2, pick the highest-precedence qualifier that remains in the list. (Start with MCC, then move down through the list.)
3. Do any of the available resource directories include this qualifier?
• If No, return to step 2 and look at the next qualifier listed in Table 2. In our example, the answer is "no" until we reach Language.
• If Yes, move on to step 4.
4. Eliminate resource directories that do not include this qualifier. In our example, we eliminate all the directories that do not include a language qualifier.

MyApp/res/drawable/
MyApp/res/drawable-en/
MyApp/res/drawable-en-port/
MyApp/res/drawable-en-notouch-12key/
MyApp/res/drawable-port-ldpi/
MyApp/res/drawable-port-notouch-12key

Exception: If the qualifier in question is screen pixel density, Android will select the option that most closely matches the device, and the selection process will be complete. In general, Android will prefer scaling down a larger original image to scaling up a smaller original image.


5. Go back and repeat steps 2, 3, and 4 until only one choice remains. In the example, screen orientation is the next qualifier in the table for which we have any matches. Eliminate resources that do not specify a screen orientation.

   MyApp/res/drawable-en/
   MyApp/res/drawable-en-port/
   MyApp/res/drawable-en-notouch-12key/

   Only one choice remains, so that's it. When drawables are called for in this example application, the Android system will load resources from the MyApp/res/drawable-en-port/ directory. In addition, if the resource being loaded is a bitmap, it will be scaled up so that its supplied low density matches the device's medium density.

현재 디바이스 설정에 일치하지 않는 임의의 리소스를 제거한다. 예를 들어 드로어블drawable에 대한 다음과 같은 리소스 디렉토리가 있다고 가정하자. drawable-fr-rCA/ 디렉토리는 제거될 것이다. 왜냐하면 그것은 디바이스의 로케일locale과 일치하지 않기 때문이다.
MyApp/res/drawable/
MyApp/res/drawable-en/
MyApp/res/drawable-fr-rCA/
MyApp/res/drawable-en-port/
MyApp/res/drawable-en-notouch-12key/
MyApp/res/drawable-port-ldpi/
MyApp/res/drawable-port-notouch-12key
Exception: 스크린 픽셀 밀도는 파일을 제거하기 위해 사용되지 않는 유일한 수식어이다. 디바이스의 스크린 픽셀 밀도가 중간medium dpi임에도 불구하고, drawable-port-ldpi/ 는 그 리스트에서 제거되지 않는다. 왜냐하면 모든 스크린 밀도가 이 시점에서 일치하는 것으로 간주되기 때문이다.
테이블 2로부터, 그 리스트에 있는 가장 높은 순위의 수식어를 골라낸다(MCC로 시작해서, 그 리스트의 아래로 이동한다).
사용가능한 리소스 디렉토리 중 어떤 것이 이 수식어를 포함하는가?
• 만약 “아니오”라면, 단계 2로 돌아가서 테이블 2에 열거된 다음 수식어를 찾는다. 우리들의 예제에서 우리가 언어에 도달할 때까지 그 답은 “아니오”이다.
• 만약 “예”라면, 단계 4로 이동한다.
이 수식어를 포함하지 않는 리소스 디렉토리를 제거한다. 우리들의 예제에서, 우리는 언어 수식어를 포함하지 않는 모든 디렉토리를 제거한다.
MyApp/res/drawable/
MyApp/res/drawable-en/
MyApp/res/drawable-en-port/
MyApp/res/drawable-en-notouch-12key/
MyApp/res/drawable-port-ldpi/
MyApp/res/drawable-port-notouch-12key
Exception: 만약 문제되는 수식어가 스크린 픽셀 밀도라면, 안드로이드는 디바이스에 가장 근접하게 일치하는 옵션을 선택할 것이다. 그리고 그 선택 절차는 완료될 것이다. 일반적으로, 안드로이드는 더 작은 원본 이미지를 키우는 것보다 더 큰 원본 이미지를 줄이는 것을 선호한다.
뒤로 돌아가서, 오직 하나의 선택이 남을 때까지 단계 2,3, 그리고 4를 반복한다. 예제에서는 스크린 오리엔테이션이 테이블에서 우리가 일치하는 다음 수식어이다. 스크린 오리엔테이션을 지정하지 않은 리소스를 제거한다.
MyApp/res/drawable-en/
MyApp/res/drawable-en-port/
MyApp/res/drawable-en-notouch-12key/
오직 하나의 선택이 남는다. 그래서 그것으로 끝난다. 이 예제 애플리케이션에서 드로어블drawable이 호출될 때, 안드로이드 시스템은 MyApp/res/drawable-en-port/ 디렉토리로부터 리소스를 로드할 것이다. 또한, 만약에 로드load된 리소스가 비트맵이라면, 제공되었던 저밀도low density 비트맵이 디바이스의 중간 밀도medium density에 맞도록 크기가 커진다.

Tip: The precedence of the qualifiers is more important than the number of qualifiers that exactly match the device. For example, in step 4 above, the last choice on the list includes three qualifiers that exactly match the device (orientation, touchscreen type, and input method), while drawable-en has only one parameter that matches (language). However, language has a higher precedence, so drawable-port-notouch-12key is out.

This flowchart summarizes how Android selects resource directories to load.

Terminology

The resource system brings a number of different pieces together to form the final complete resource functionality. To help understand the overall system, here are some brief definitions of the core concepts and components you will encounter in using it:

Asset: A single blob of data associated with an application. This includes object files compiled from the Java source code, graphics (such as PNG images), XML files, etc. These files are organized in a directory hierarchy that, during final packaging of the application, is bundled together into a single ZIP file.

aapt: Android Asset Packaging Tool. The tool that generates the final ZIP file of application assets. In addition to collecting raw assets together, it also parses resource definitions into binary asset data.

Resource Table: A special asset that aapt generates for you, describing all of the resources contained in an application/package. This file is accessed for you by the Resources class; it is not touched directly by applications.

Resource: An entry in the Resource Table describing a single named value. Broadly, there are two types of resources: primitives and bags.

Resource Identifier: In the Resource Table all resources are identified by a unique integer number. In source code (resource descriptions, XML files, Java source code) you can use symbolic names that stand as constants for the actual resource identifier integer.

Primitive Resource: All primitive resources can be written as a simple string, using formatting to describe a variety of primitive types included in the resource system: integers, colors, strings, references to other resources, etc. Complex resources, such as bitmaps and XML describes, are stored as a primitive string resource whose value is the path of the underlying Asset holding its actual data.

Bag Resource: A special kind of resource entry that, instead of a simple string, holds an arbitrary list of name/value pairs. Each name is itself a resource identifier, and each value can hold the same kinds of string formatted data as a normal resource. Bags also support inheritance: a bag can inherit the values from another bag, selectively replacing or extending them to generate its own contents.

Kind: The resource kind is a way to organize resource identifiers for various purposes. For example, drawable resources are used to instantiate Drawable objects, so their data is a primitive resource containing either a color constant or string path to a bitmap or XML asset. Other common resource kinds are string (localized string primitives), color (color primitives), layout (a string path to an XML asset describing a view layout), and style (a bag resource describing user interface attributes). There is also a standard "attr" resource kind, which defines the resource identifiers to be used for naming bag items and XML attributes

Style: The name of the resource kind containing bags that are used to supply a set of user interface attributes. For example, a TextView class may be given a style resource that defines its text size, color, and alignment. In a layout XML file, you associate a style with a bag using the "style" attribute, whose value is the name of the style resource.

Style Class: Specifies a related set of attribute resources. This data is not placed in the resource table itself, but used to generate constants in the source code that make it easier for you to retrieve values out of a style resource and/or XML tag's attributes. For example, the Android platform defines a "View" style class that contains all of the standard view attributes: padding, visibility, background, etc.; when View is inflated it uses this style class to retrieve those values from the XML file (at which point style and theme information is applied as approriate) and load them into its instance.

Configuration: For any particular resource identifier, there may be multiple different available values depending on the current configuration. The configuration includes the locale (language and country), screen orientation, etc. The current configuration is used to select which resource values are in effect when the resource table is loaded.

Theme: A standard style resource that supplies global attribute values for a particular context. For example, when writing an Activity the application developer can select a standard theme to use, such as the Theme.White or Theme.Black styles; this style supplies information such as the screen background image/color, default text color, button style, text editor style, text size, etc. When inflating a layout resource, most values for widgets (the text color, selector, background) if not explicitly set will come from the current theme; style and attribute values supplied in the layout can also assign their value from explicitly named values in the theme attributes if desired.

Overlay: A resource table that does not define a new set of resources, but instead replaces the values of resources that are in another resource table. Like a configuration, this is applied at load time to the resource data; it can add new configuration values (for example strings in a new locale), replace existing values (for example change the standard white background image to a "Hello Kitty" background image), and modify resource bags (for example change the font size of the Theme.White style to have an 18 pt font size). This is the facility that allows the user to select between different global appearances of their device, or download files with new appearances.

Resource Reference

The Available Resources document provides a detailed list of the various types of resource and how to use them from within the Java source code, or from other references.

Internationalization and Localization

Coming Soon: Internationalization and Localization are critical, but are also not quite ready yet in the current SDK. As the SDK matures, this section will contain information on the Internationalization and Localization features of the Android platform. In the meantime, it is a good idea to start by externalizing all strings, and practicing good structure in creating and using resources.