<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<ListView android:id="@android:id/list"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<TextView android:id="@android:id/empty"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/no_notes"/>
<TextView android:id="@+id/text1"
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
</LinearLayout>
- @告诉XML解析器后面的是一个资源引用，+意味着如果没有这个资源就创建一个
- list和empty ID是Android平台提供的，因此要加上android: 前缀
- layout文件下的每一个xml文件在R.java中都有一个class对应，其中的每一个资源在R.java中都有相应的入口，以便在应用程序中方便的引用
- The android.R class is a set of predefined resources provided for you by the platform, while your project's R class is the set of resources your project has defined. Resources found in the android.R resource class can be used in the XML files by using the android: name space prefix (as we see here).
-
Most Activity classes will have a layout associated with them. The layout will be the "face" of the Activity to the user. In this case our layout will take over the whole screen and provide a list of notes.Full screen layouts are not the only option for an Activity however. You might also want to use a floating layout (for example, a dialog or alert), or perhaps you don't need a layout at all (the Activity will be invisible to the user unless you specify some kind of layout for it to use).
- This example uses a SimpleCursorAdapter to bind a database Cursor into a ListView, and this is a common way to use a ListAdapter. Other options exist like ArrayAdapter which can be used to take a List or Array of in-memory data and bind it in to a list as well.
http://www.chinaup.org/docs/intro/tutorial-ex1.html