android Launcher源码解析01：UI格局详解一

android Launcher源码解析01：UI布局详解一

        本系列文章将开始android lancher源码分析，使用的例子是android 2.3中自带的launcher3源码。其下载地址为：

        本文为第一篇文章，介绍一下lancher的UI布局。

1、布局

      运行该APK，则其执行结果为：

       

      按home键以后：

2、布局文件

       我们来看一下，lancher的布局文件launcher.xml，其源码为：

<com.android.launcher3.DragLayer xmlns:android="http://schemas.android.com/apk/res/android" xmlns:launcher="http://schemas.android.com/apk/res/com.android.launcher3" android:id="@+id/drag_layer" android:layout_width="match_parent" android:layout_height="match_parent"> <include layout="@layout/all_apps" /> <!-- The workspace contains 3 screens of cells --> <com.android.launcher3.Workspace android:id="@+id/workspace" android:layout_width="match_parent" android:layout_height="match_parent" android:scrollbars="horizontal" android:fadeScrollbars="true" launcher:defaultScreen="2"> <include android:id="@+id/cell1" layout="@layout/workspace_screen" /> <include android:id="@+id/cell2" layout="@layout/workspace_screen" /> <include android:id="@+id/cell3" layout="@layout/workspace_screen" /> <include android:id="@+id/cell4" layout="@layout/workspace_screen" /> <include android:id="@+id/cell5" layout="@layout/workspace_screen" /> </com.android.launcher3.Workspace> <com.android.launcher3.ClippedImageView android:id="@+id/previous_screen" android:layout_width="93dip" android:layout_height="@dimen/button_bar_height" android:layout_gravity="bottom|left" android:layout_marginLeft="6dip" android:scaleType="center" android:src="@drawable/home_arrows_left" android:onClick="previousScreen" launcher:ignoreZone="56dip" android:focusable="true" android:clickable="true" /> <com.android.launcher3.ClippedImageView android:id="@+id/next_screen" android:layout_width="93dip" android:layout_height="@dimen/button_bar_height" android:layout_gravity="bottom|right" android:layout_marginRight="6dip" android:scaleType="center" android:src="@drawable/home_arrows_right" android:onClick="nextScreen" launcher:ignoreZone="-56dip" android:focusable="true" android:clickable="true" /> <com.android.launcher3.DeleteZone android:id="@+id/delete_zone" android:layout_width="@dimen/delete_zone_size" android:layout_height="@dimen/delete_zone_size" android:paddingLeft="@dimen/delete_zone_padding" android:layout_marginBottom="@dimen/half_status_bar_height" android:layout_gravity="right|center_vertical" android:scaleType="center" android:src="@drawable/delete_zone_selector" android:visibility="invisible" launcher:direction="vertical" /> <RelativeLayout android:id="@+id/all_apps_button_cluster" android:layout_height="fill_parent" android:layout_width="@dimen/button_bar_height_portrait" android:layout_gravity="right|center_vertical" android:layout_marginBottom="@dimen/half_status_bar_height" > <com.android.launcher3.HandleView style="@style/HotseatButton" android:id="@+id/all_apps_button" android:layout_centerVertical="true" android:layout_alignParentRight="true" android:src="@drawable/all_apps_button" launcher:direction="vertical" /> <ImageView android:id="@+id/hotseat_left" style="@style/HotseatButton.Left" android:layout_below="@id/all_apps_button" android:src="@drawable/hotseat_phone" android:onClick="launchHotSeat" /> <ImageView android:id="@+id/hotseat_right" style="@style/HotseatButton.Right" android:layout_above="@id/all_apps_button" android:src="@drawable/hotseat_browser" android:onClick="launchHotSeat" /> </RelativeLayout> </com.android.launcher3.DragLayer>3、布局文件分析      

  针对其中的各个部分，其图形为：

• launcher的第一层次UI 是DragLayer