Accessing Resources

阅读：http://developer.android.com/guide/topics/resources/accessing-resources.html

 

Although the R class is where resource IDs are specified, you should never need to look there to discover a resource ID. A resource ID is always composed of:

• The resource type: Each resource is grouped into a "type," such as string, drawable, and layout. For more about the different types, see Resource Types.
• The resource name, which is either: the filename, excluding the extension; or the value in the XML android:name attribute, if the resource is a simple value (such as a string).

　　R会为每一个res下的文件建立唯一的ID，ID的引用一般是 文件类型.文件名.文件扩展名。

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有两个方法可以进行访问：1、代码中使用R.XXX.XXX进行访问；2、在布局文件使用类似@string/hello的方法进行访问；

 

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You can use a resource in code by passing the resource ID as a method parameter. For example, you can set an ImageView to use the res/drawable/myimage.png resource using setImageResource():

ImageView imageView =(ImageView) findViewById(R.id.myimageview);
imageView.setImageResource(R.drawable.myimage);

You can also retrieve individual resources using methods in Resources, which you can get an instance of with getResources().

　　语法：[<package_name>.]R.<resource_type>.<resource_name>

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　　资源使用举例：

　　

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

// Set the Activity title by getting a string from the Resources object, because
//  this method requires a CharSequence rather than a resource ID
getWindow().setTitle(getResources().getText(R.string.main_title));

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

// Set a slide in animation by getting an Animation from the Resources object
mFlipper.setInAnimation(AnimationUtils.loadAnimation(this,
        R.anim.hyperspace_in));

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

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XML使用方法：

语法：@[<package_name>:]<resource_type>/<resource_name> 

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

如果用自己包的文件就不用加包名了，但是如果使用系统的VALUES，则需要加上包名。