Android手机屏幕相关知识（launcher2中）

1、屏幕数量launcher.java

  原来：
    static final int SCREEN_COUNT = 5; // 五屏  
    static final int DEFAULT_SCREEN = 2; // 默认屏幕为中间的屏幕  

 改成：
    static final int SCREEN_COUNT = 1; // 一个屏  
    static final int DEFAULT_SCREEN = 0; // 默认屏幕为中间的屏幕  

注：当java 文件修改了，则对应的launcher.xml文件也要修改，一个横屏的xml文件，一个竖屏的
res/layout-land/launcher.xml

  原来：
    <com.android.launcher2.Workspace  
              android:id="@+id/workspace"  
              android:layout_width="match_parent"  
              android:layout_height="match_parent"  
              android:paddingLeft="@dimen/workspace_left_padding"  
              android:paddingRight="@dimen/workspace_right_padding"  
              android:paddingTop="@dimen/workspace_top_padding"  
              android:paddingBottom="@dimen/workspace_bottom_padding"  
              launcher:defaultScreen="2"  
              launcher:cellCountX="@integer/cell_count_x"  
              launcher:cellCountY="@integer/cell_count_y"  
              launcher:pageSpacing="@dimen/workspace_page_spacing"  
              launcher:scrollIndicatorPaddingLeft="@dimen/qsb_bar_height"  
              launcher:scrollIndicatorPaddingRight="@dimen/button_bar_height">  
      
              <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.launcher2.Workspace>  

改成：
    <com.android.launcher2.Workspace  
        android:id="@+id/workspace"  
        android:layout_width="match_parent"  
        android:layout_height="match_parent"  
        android:paddingLeft="@dimen/workspace_left_padding"  
        android:paddingRight="@dimen/workspace_right_padding"  
        android:paddingTop="@dimen/workspace_top_padding"  
        android:paddingBottom="@dimen/workspace_bottom_padding"  
        launcher:defaultScreen="0"  
        launcher:cellCountX="@integer/cell_count_x"  
        launcher:cellCountY="@integer/cell_count_y"  
        launcher:pageSpacing="@dimen/workspace_page_spacing"  
        launcher:scrollIndicatorPaddingLeft="@dimen/qsb_bar_height"  
        launcher:scrollIndicatorPaddingRight="@dimen/button_bar_height">  
      
        <include android:id="@+id/cell1" layout="@layout/workspace_screen" />  
      
    </com.android.launcher2.Workspace>  

同理，res/layout-port/launcher.xml也是这样修改

2、