android Launcher AppWidget添加步驟介紹

更新時(shí)間：2022年01月07日 10:44:12 作者：空間維度

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一、AppWidget開機(jī)啟動(dòng)加載

Android系統(tǒng)啟動(dòng)，SystemServer創(chuàng)建AppWidgetService，并調(diào)用AppWidgetServiceImpl.onStart()方法，初始化相關(guān)管理器，注冊(cè)四個(gè)廣播接收器:

第一、注冊(cè)有關(guān)軟件包安裝、刪除、改變的廣播，以便我們可以更新provider列表。;

        // Register for broadcasts about package install, etc., so we can
        // update the provider list.
        IntentFilter packageFilter = new IntentFilter();
        packageFilter.addAction(Intent.ACTION_PACKAGE_ADDED);
        packageFilter.addAction(Intent.ACTION_PACKAGE_CHANGED);
        packageFilter.addAction(Intent.ACTION_PACKAGE_REMOVED);
        packageFilter.addDataScheme("package");
        mContext.registerReceiverAsUser(mBroadcastReceiver, UserHandle.ALL,
                packageFilter, null, null);

第二、當(dāng)鎖定狀態(tài)發(fā)生變化時(shí)會(huì)播放一些事件:

        IntentFilter offModeFilter = new IntentFilter();
        offModeFilter.addAction(Intent.ACTION_MANAGED_PROFILE_AVAILABLE);
        offModeFilter.addAction(Intent.ACTION_MANAGED_PROFILE_UNAVAILABLE);
        mContext.registerReceiverAsUser(mBroadcastReceiver, UserHandle.ALL,
                offModeFilter, null, null);

第三、暫?；蚪獬龝和?yīng)用廣播;

        IntentFilter offModeFilter = new IntentFilter();
        offModeFilter.addAction(Intent.ACTION_MANAGED_PROFILE_AVAILABLE);
        offModeFilter.addAction(Intent.ACTION_MANAGED_PROFILE_UNAVAILABLE);
        mContext.registerReceiverAsUser(mBroadcastReceiver, UserHandle.ALL,
                offModeFilter, null, null);

第四、注冊(cè)sdcard的安裝與卸載的廣播。

        // Register for events related to sdcard installation.
        IntentFilter sdFilter = new IntentFilter();
        sdFilter.addAction(Intent.ACTION_EXTERNAL_APPLICATIONS_AVAILABLE);
        sdFilter.addAction(Intent.ACTION_EXTERNAL_APPLICATIONS_UNAVAILABLE);
        mContext.registerReceiverAsUser(mBroadcastReceiver, UserHandle.ALL,
                sdFilter, null, null);

二、Launcher3啟動(dòng)添加

Launcher啟動(dòng)onCreate()方法初始化mAppWidgetManager, mAppWidgetHost對(duì)象，AppWidgetHost是launcher承載AppWidgetView的宿主
mAppWidgetHost.startListening，通過

public void onCreate() {
    ...
    // 13      //得到AppWidget管理實(shí)例 ： AppWidgetManager , AppWidgetHost , AppWidgetHostView三個(gè)類的關(guān)系

    mAppWidgetManager = AppWidgetManagerCompat.getInstance(this);

    mAppWidgetHost = new LauncherAppWidgetHost(this);
    // Host啟動(dòng)監(jiān)聽,監(jiān)聽LauncherProvider中的數(shù)據(jù)改變
    mAppWidgetHost.startListening();
    ...
}

1、初始化AppWidgetHostd對(duì)象，創(chuàng)建用于回調(diào)的Callbacks服務(wù)類IAppWidgetHost.Stub, 綁定服務(wù)bindService，得到IAppWidgetService對(duì)象，進(jìn)行l(wèi)auncher和AppWidgetService之間的調(diào)用

public AppWidgetHost(Context context, int hostId, InteractionHandler handler, Looper looper) {
        mContextOpPackageName = context.getOpPackageName();
        mHostId = hostId;
        mInteractionHandler = handler;
        mHandler = new UpdateHandler(looper);
        mCallbacks = new Callbacks(mHandler);
        mDisplayMetrics = context.getResources().getDisplayMetrics();
        bindService(context);
    }

2、在startListening 方法中 ，通過IAppWidgetService.startListening 方法解析Launcher中的AppWidget信息保存到系統(tǒng)服務(wù)成員變量中，
3、當(dāng)添加AppWidget時(shí)，首頁(yè)返回到Launcher中的onActivityResult中，在handleActivityResult中

        addAppWidgetImpl(
                        appWidgetId, requestArgs, null,
                        requestArgs.getWidgetHandler(),
                        ON_ACTIVITY_RESULT_ANIMATION_DELAY);

創(chuàng)建添加小部件意圖，之后返回到onActivityForResult,調(diào)用completeAddAppWidget，通過IAppWidgetService.getAppWidgetInfo,獲取AppWidgetProviderInfo,保存到本地?cái)?shù)據(jù)庫(kù)中addItemToDatabase()，

 @Thunk void completeAddAppWidget(int appWidgetId, ItemInfo itemInfo,
1070            AppWidgetHostView hostView, LauncherAppWidgetProviderInfo appWidgetInfo) {
1071
1072        if (appWidgetInfo == null) {
1073            appWidgetInfo = mAppWidgetManager.getLauncherAppWidgetInfo(appWidgetId);
1074        }
1075
1076        LauncherAppWidgetInfo launcherInfo;
1077        launcherInfo = new LauncherAppWidgetInfo(appWidgetId, appWidgetInfo.provider);
1078        launcherInfo.spanX = itemInfo.spanX;
1079        launcherInfo.spanY = itemInfo.spanY;
1080        launcherInfo.minSpanX = itemInfo.minSpanX;
1081        launcherInfo.minSpanY = itemInfo.minSpanY;
1082        launcherInfo.user = appWidgetInfo.getProfile();
1083
1084        getModelWriter().addItemToDatabase(launcherInfo,
1085                itemInfo.container, itemInfo.screenId, itemInfo.cellX, itemInfo.cellY);
1086
1087        if (hostView == null) {
1088            // Perform actual inflation because we're live
1089            hostView = mAppWidgetHost.createView(this, appWidgetId, appWidgetInfo);
1090        }
1091        hostView.setVisibility(View.VISIBLE);
1092        prepareAppWidget(hostView, launcherInfo);
1093        mWorkspace.addInScreen(hostView, launcherInfo);
1094    }
1095
1096    private void prepareAppWidget(AppWidgetHostView hostView, LauncherAppWidgetInfo item) {
1097        hostView.setTag(item);
// 計(jì)算AppWidget的顯示大小位置
1098        item.onBindAppWidget(this, hostView);
1099        hostView.setFocusable(true);
1100        hostView.setOnFocusChangeListener(mFocusHandler);
1101    }

并創(chuàng)建AppWidgetHostView 對(duì)象，mAppWidgetHost.createView，返回RemoteView對(duì)象，IAppWidgetService。getAppWidgetViews（）

public final AppWidgetHostView createView(Context context, int appWidgetId,
            AppWidgetProviderInfo appWidget) {
        if (sService == null) {
            return null;
        }
        AppWidgetHostView view = onCreateView(context, appWidgetId, appWidget);
        view.setInteractionHandler(mInteractionHandler);
        view.setAppWidget(appWidgetId, appWidget);
        synchronized (mViews) {
            mViews.put(appWidgetId, view);
        }
        RemoteViews views;
        try {
            views = sService.getAppWidgetViews(mContextOpPackageName, appWidgetId);
        } catch (RemoteException e) {
            throw new RuntimeException("system server dead?", e);
        }
        view.updateAppWidget(views);

        return view;
    }

調(diào)用AppWidgetHostView.updateAppWidget(views);更新View到launcher界面上mWorkspace.addInScreen(hostView, launcherInfo);

當(dāng)AppWidgetProvider獲得更新的廣播，并執(zhí)行onUpdate()，onUpdate()中創(chuàng)建了RemoteViews并通過AppWidgetManager.updateAppWidget()更新到AppWidgetService之后，AppWidgetService會(huì)通過注冊(cè)的IAppWidgetHost的回調(diào)，執(zhí)行AppWidgetHost的更新。

總結(jié)

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