Android-Launcher

Android-Launcher

一 Launcher的简单研究
1，什么是Launcher：Android系统启动后加载的第一个程序，是其他应用程序的入口
2，专业术语：
HomeScreen：
(workspace+hotseats)整个屏幕

shortcut快捷方式

livefolder活动文件夹

appwidget小组件

wallpaper墙纸

hotseats热底座

AllAppList：(GridView,哈希表)

二 launcher的开发类型
1，开发自己的launcher
2，在workspace中添加：
添加shortcut
添加livefolder
更改背景wallpaper
添加小组件appwidget

三 分析launcher.java的onCreate方法

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    //实例化一些对象
        LauncherApplication app = ((LauncherApplication)getApplication());
        mModel = app.setLauncher(this);
        mIconCache = app.getIconCache();
        mDragController = new DragController(this);
        mInflater = getLayoutInflater();
    //实例化对象
        mAppWidgetManager = AppWidgetManager.getInstance(this);
        mAppWidgetHost = new LauncherAppWidgetHost(this, APPWIDGET_HOST_ID);
        mAppWidgetHost.startListening();

        if (PROFILE_STARTUP) {
            android.os.Debug.startMethodTracing("/sdcard/launcher");
        }
    //加载热底座
        loadHotseats();
    //检查本地化语言
        checkForLocaleChange();
    //设置墙纸
        setWallpaperDimension();
    //设置布局的layout
        setContentView(R.layout.launcher);
        setupViews();
    //注册contentprovider的数据观察，观察它里面的数据变化
        registerContentObservers();

        lockAllApps();
    //状态的恢复和保存
        mSavedState = savedInstanceState;
        restoreState(mSavedState);

        if (PROFILE_STARTUP) {
            android.os.Debug.stopMethodTracing();
        }

        if (!mRestoring) {
            mModel.startLoader(this, true);
        }

        // For handling default keys
        mDefaultKeySsb = new SpannableStringBuilder();
        Selection.setSelection(mDefaultKeySsb, 0);

        IntentFilter filter = new IntentFilter(Intent.ACTION_CLOSE_SYSTEM_DIALOGS);
        //动态注册receiver
        registerReceiver(mCloseSystemDialogsReceiver, filter);
    }

四 HomeScreen可以添加的四大组件：

/**
         * Handle the action clicked in the "Add to home" dialog.
         */
        public void onClick(DialogInterface dialog, int which) {
            Resources res = getResources();
            cleanup();

            switch (which) {
        //添加shortcut
                case AddAdapter.ITEM_SHORTCUT: {
                    // Insert extra item to handle picking application
                    pickShortcut();
                    break;
                }
        //添加Appwidget
                case AddAdapter.ITEM_APPWIDGET: {
                    int appWidgetId = Launcher.this.mAppWidgetHost.allocateAppWidgetId();

                    Intent pickIntent = new Intent(AppWidgetManager.ACTION_APPWIDGET_PICK);
                    pickIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);
                    // start the pick activity
                    startActivityForResult(pickIntent, REQUEST_PICK_APPWIDGET);
                    break;
                }
        //添加liveforlder
                case AddAdapter.ITEM_LIVE_FOLDER: {
                    // Insert extra item to handle inserting folder
                    Bundle bundle = new Bundle();

                    ArrayList<String> shortcutNames = new ArrayList<String>();
                    shortcutNames.add(res.getString(R.string.group_folder));
                    bundle.putStringArrayList(Intent.EXTRA_SHORTCUT_NAME, shortcutNames);

                    ArrayList<ShortcutIconResource> shortcutIcons =
                            new ArrayList<ShortcutIconResource>();
                    shortcutIcons.add(ShortcutIconResource.fromContext(Launcher.this,
                            R.drawable.ic_launcher_folder));
                    bundle.putParcelableArrayList(Intent.EXTRA_SHORTCUT_ICON_RESOURCE, shortcutIcons);

                    Intent pickIntent = new Intent(Intent.ACTION_PICK_ACTIVITY);
                    pickIntent.putExtra(Intent.EXTRA_INTENT,
                            new Intent(LiveFolders.ACTION_CREATE_LIVE_FOLDER));
                    pickIntent.putExtra(Intent.EXTRA_TITLE,
                            getText(R.string.title_select_live_folder));
                    pickIntent.putExtras(bundle);

                    startActivityForResult(pickIntent, REQUEST_PICK_LIVE_FOLDER);
                    break;
                }
        //改变墙纸
                case AddAdapter.ITEM_WALLPAPER: {
                    startWallpaper();
                    break;
                }
            }
        }

        public void onShow(DialogInterface dialog) {
            mWaitingForResult = true;            
        }
    }

//Activity的返回值回调方法，返回的时候都需要调用
@Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        mWaitingForResult = false;

        // The pattern used here is that a user PICKs a specific application,
        // which, depending on the target, might need to CREATE the actual target.

        // For example, the user would PICK_SHORTCUT for "Music playlist", and we
        // launch over to the Music app to actually CREATE_SHORTCUT.

        if (resultCode == RESULT_OK && mAddItemCellInfo != null) {
            switch (requestCode) {
        //调用的过程
                case REQUEST_PICK_APPLICATION:
                    completeAddApplication(this, data, mAddItemCellInfo);
                    break;
                case REQUEST_PICK_SHORTCUT:
                    processShortcut(data);
                    break;
                case REQUEST_CREATE_SHORTCUT:
                    completeAddShortcut(data, mAddItemCellInfo);
                    break;
                case REQUEST_PICK_LIVE_FOLDER:
                    addLiveFolder(data);
                    break;
                case REQUEST_CREATE_LIVE_FOLDER:
                    completeAddLiveFolder(data, mAddItemCellInfo);
                    break;
                case REQUEST_PICK_APPWIDGET:
                    addAppWidget(data);
                    break;
                case REQUEST_CREATE_APPWIDGET:
                    completeAddAppWidget(data, mAddItemCellInfo);
                    break;
                case REQUEST_PICK_WALLPAPER:
                    // We just wanted the activity result here so we can clear mWaitingForResult
                    break;
            }
        } else if ((requestCode == REQUEST_PICK_APPWIDGET ||
                requestCode == REQUEST_CREATE_APPWIDGET) && resultCode == RESULT_CANCELED &&
                data != null) {
            // Clean up the appWidgetId if we canceled
            int appWidgetId = data.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, -1);
            if (appWidgetId != -1) {
                mAppWidgetHost.deleteAppWidgetId(appWidgetId);
            }
        }
    }

添加shortcut的具体过程：
onClick->pickShortcut()->返回给launcher的Activity
processShortcut(Intent intent)->返回给launcher的Activity->
completeAddShortcut(Intent data, CellLayout.CellInfo cellInfo)
UML：

下面三个与shortcut类似
livefolder
appwidget
wallpaper