Launcher2折腾之路(3)

Launcher2中的壁纸选择器在Launcher2 这个Application中是一个Activity，先看一下Manifest.xml

1	<activity
2	android:name="com.android.launcher2.WallpaperChooser"
3	android:theme="@style/Theme.WallpaperPicker"
4	android:label="@string/pick_wallpaper"
5	android:icon="@mipmap/ic_launcher_wallpaper"
6	android:finishOnCloseSystemDialogs="true"
7	android:process=":wallpaper_chooser">
8	<intent-filter>
9	<action android:name="android.intent.action.SET_WALLPAPER" />
10	<category android:name="android.intent.category.DEFAULT" />
11	</intent-filter>
12	<meta-data android:name="android.wallpaper.preview"
13	android:resource="@xml/wallpaper_picker_preview" />
14	</activity>

1,壁纸选择器的启动方式有两种，一种是在Workspace的空白处长按，另外一种是在Workspace按MENU键

a,长按启动

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->

startWallpaper();

->

startActivityForResult(chooser, REQUEST_PICK_WALLPAPER );

其中chooser 是一个Intent

final Intent pickWallpaper = new Intent(Intent.ACTION_SET_WALLPAPER );

=>启动了wallpaperChooser Activity

WallpaperChooser.java

=>

WallpaperChooserDialogFragment. newInstance();

=>

WallpaperChooserDialogFragment.java

public static WallpaperChooserDialogFragment newInstance() {

        WallpaperChooserDialogFragment fragment = new WallpaperChooserDialogFragment();

        fragment.setCancelable( true);

return fragment;

    }

启动的这个小窗口就是一个DialogFragment

先看这下WallpaperChooser 这个Activity的布局

wallpaper_chooser_base.xml调用wallpaper_chooser.xml

里面三个就是一个ListView的View

     <Gallery android:id="@+id/gallery"

            android:layout_width="match_parent"

            android:layout_height="wrap_content"

            android:spacing="-4dp" />

大概Layout如下

b,menu启动

重写onCreateOptionsMenu()

@Override

public boolean onCreateOptionsMenu (Menu menu) {

增加wallpaper的选项

menu.add(MENU_GROUP_WALLPAPER, MENU_WALLPAPER_SETTINGS, 0, R.string.menu_wallpaper)

            .setIcon(android.R.drawable. ic_menu_gallery)

            .setAlphabeticShortcut( 'W');

在onOptionsItemSelected（）函数是响应这个Item选择。殊途同归。

case MENU_WALLPAPER_SETTINGS :

startWallpaper();

return true;

        }

2，Question:

为什么在workspace界面按menu有wallpaper的选项，而在customerview/all app 却没有wallpaper的选项。暂时还没找到逻辑。