Launcher2折腾之路(1)

来源：互联网发布：林白的过程解析知乎编辑：程序博客网时间：2024/06/05 08:41

想自己写一个Launcher，但无从下手，那就从Launcher2源码开刀吧。一味的看源码也不是个事，那就自己动手折腾，修改Launcher来加深对Launcher的理解。

1，把work_space中的cell默认是5个，要整成1个。我的屏幕的size是720P-50hz，对应的Layout文件夹是layout-sw720dp/。我也不知道怎么对应上的，一个一个试的。——!!!

                   1            -    static final int SCREEN_COUNT = 5;                        2            -    static final int DEFAULT_SCREEN = 2;                        3            +    static final int SCREEN_COUNT = 1;//5;                        4            +    static final int DEFAULT_SCREEN =0;// 2;                        5            WorkSpace.Java             

                   1            --- a/res/layout-sw720dp/launcher.xml                        2            +++ b/res/layout-sw720dp/launcher.xml                        3            @@ -57,7 +57,7 @@                        4                         android:paddingEnd="@dimen/workspace_right_padding"                        5                         android:paddingTop="@dimen/workspace_top_padding"                        6                         android:paddingBottom="@dimen/workspace_bottom_padding"                        7            -            launcher:defaultScreen="2"                        8            +            launcher:defaultScreen="0"                        9                         launcher:cellCountX="@integer/cell_count_x"                        10                         launcher:cellCountY="@integer/cell_count_y"                        11                         launcher:pageSpacing="@dimen/workspace_page_spacing"                        12            @@ -65,10 +65,10 @@                        13                         launcher:scrollIndicatorPaddingRight="@dimen/workspace_divider_padding_right">                        14                                     15                         <include android:id="@+id/cell1" layout="@layout/workspace_screen" />                        16            -            <include android:id="@+id/cell2" layout="@layout/workspace_screen" />                        17            +          <!--   <include android:id="@+id/cell2" layout="@layout/workspace_screen" />                        18                         <include android:id="@+id/cell3" layout="@layout/workspace_screen" />                        19                         <include android:id="@+id/cell4" layout="@layout/workspace_screen" />                        20            -            <include android:id="@+id/cell5" layout="@layout/workspace_screen" />                        21            +            <include android:id="@+id/cell5" layout="@layout/workspace_screen" /> -->                        22                     </com.android.launcher2.Workspace>                        23                          

2，APPS_CUSTOMIZE界面的Icon后面加背景图片

                   1            if (true)                        2                        {                        3                            Bitmap backBitmap = BitmapFactory.decodeResource(context.getResources(),                        4                                    R.drawable. icon_back);                        5                            int backWidth = backBitmap.getWidth();                        6                            int backHeight = backBitmap.getHeight();                        7                            Log. i(Launcher.TAG,"koffu pic width=" + backWidth + ", width=" + backHeight);                        8                            Log. i(Launcher .TAG ,"koffu sIconwidth=" + sIconWidth + ", sIconHeight=" + sIconHeight);                        9                            if(backWidth != sIconWidth || backHeight != sIconHeight)                        10                            {                        11                                Matrix matrix = new Matrix();                        12                                matrix.postScale((float)sIconWidth /backWidth, (float)sIconHeight /backHeight);                        13                                canvas.drawBitmap(Bitmap.createBitmap(backBitmap, 0, 0, backWidth, backHeight, matrix, true ),                        14                                        0.0f, 0.0f, null);                        15                            } else                        16                            {                        17                                canvas.drawBitmap(backBitmap, 0.0f, 0.0f, null);                        18                            }                        19                        }                        20                          

效果如下（每个icon后面都有一个熊孩子图片）：

稍微延伸一下：

Canvas/Bitmap/Matrix这三个类的关系
Bitmap这个类主要是用来“获取”“承装”位置的类
Canvas这个类主要是用来“绘制”位图的类
Matrix这个类主要是用来“缩放”“旋转”的类
具体可以参考：http://www.cnblogs.com/feisky/archive/2010/01/10/1643460.html

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