本文實例講述了Android7.0開發實現Launcher3去掉應用抽屜的方法。分享給大家供大家參考，具體如下：
年初做過一個項目，有一個需求就是需要將桌面變為單層不需要二級菜單。最近幾次有小伙伴有這個問我這個解決辦法。現在我將分享給大家。
先上效果圖:
功能分解
1. 去除Allapp鍵，調整HotSeat布局
2. 將所有應用擺在launcher第一層
3. 去掉長按時刪除選項
解決方案
一、設置總開關
按照6.0 Launcher3 的模式，添加一個開關，控制是否去掉抽屜。
LauncherAppState類:單例模式，主要在啟動的時候用，他初始化了一些對象，并且注冊了廣播監聽器和ContentObserver。為了能靈活切換模式,在此類中添加靜態開關。
Launcher3/src/com/android/launcher3/LauncherAppState.java:
public static boolean isDisableAllApps() { // Returns false on non-dogfood builds. return android.os.SystemProperties.get("ro.wind.launcher3.ishome2","0").equals("1");}二、Allapp鍵的加載
在HotSeat里面去掉Allapp鍵的加載 ，屏蔽isAllAppsButtonRank()占用allapp位置。
1) 不再占用allapp位置
2) 在加載Workspace時,會留出HotSeat的第三個位置給allapp按鈕,若不取消該位置的占用,在HotSeat加載時會留出空位。HotSeat的初始化在HotSeat.java中
Launcher3/src/com/android/launcher3/HotSeat.java –>isAllAppsButtonRank():
public boolean isAllAppsButtonRank(int rank) { //添加 @{ if (LauncherAppState.isDisableAllApps()) { return false; } //添加 @} return rank == mAllAppsButtonRank;}3) Home2沒有抽屜，所以不需要allapp按鈕。在HotSeat里面去掉Allapp鍵的加載，在HotSeat.java 的void resetLayout()中初始化HotSeat布局。在Home2時停止加載Allapp按鈕。
Launcher3/src/com/android/launcher3/HotSeat.java –>resetLayout():
void resetLayout() { mContent.removeAllViewsInLayout(); //添加 @{ if(LauncherAppState.isDisableAllApps()){ //添加 }@ // Add the Apps button Context context = getContext(); LayoutInflater inflater = LayoutInflater.from(context); TextView allAppsButton = (TextView) inflater.inflate(R.layout.all_apps_button, mContent, false); Drawable d = context.getResources().getDrawable(R.drawable.all_apps_button_icon); mLauncher.resizeIconDrawable(d); allAppsButton.setCompoundDrawables(null, d, null, null); allAppsButton.setContentDescription(context.getString(R.string.all_apps_button_label)); allAppsButton.setOnKeyListener(new HotseatIconKeyEventListener()); if (mLauncher != null) { mLauncher.setAllAppsButton(allAppsButton); allAppsButton.setOnTouchListener(mLauncher.getHapticFeedbackTouchListener()); allAppsButton.setOnClickListener(mLauncher); allAppsButton.setOnLongClickListener(mLauncher); allAppsButton.setOnFocusChangeListener(mLauncher.mFocusHandler); } // Note: We do this to ensure that the hotseat is always laid out in the orientation of // the hotseat in order regardless of which orientation they were added int x = getCellXFromOrder(mAllAppsButtonRank); int y = getCellYFromOrder(mAllAppsButtonRank); CellLayout.LayoutParams lp = new CellLayout.LayoutParams(x,y,1,1); lp.canReorder = false; mContent.addViewToCellLayout(allAppsButton, -1, allAppsButton.getId(), lp, true); }}//別漏了這里的 }三、數據初始化類中更改HotSeat布局
InvariantDeviceProfile.java Launcher3進行布局初始化的一個類。
在有allapp按鈕時HotSeat里Hotseat圖標數量為五個，沒有allapp按鈕時Hotseat圖標數量應為四個。
Launcher3/src/com/android/launcher3/InvariantDeviceProfile.java:
1)先加個宏控
//添加 @{private boolean hasDA = LauncherAppState.isDisableAllApps();//添加 }@2)去掉抽屜時，HotSeat的格數為四格，所以不能拋出異常。 ( numHotseatIcons 為偶時不拋異常)
InvariantDeviceProfile( ):
InvariantDeviceProfile(String n, float w, float h, int r, int c, int fr, int fc, int maapc, // Ensure that we have an odd number of hotseat items (since we need to place all apps) if (hs % 2 == 0&& !hasDA) {// 在無抽屜情況下不拋異常 throw new RuntimeException("All Device Profiles must have an odd number of hotseat spaces"); } name = n; ... ...}3)去掉抽屜的情況下加載不同的布局
getPredefinedDeviceProfiles() :
ArrayList<InvariantDeviceProfile> getPredefinedDeviceProfiles() { ArrayList<InvariantDeviceProfile> predefinedDeviceProfiles = new ArrayList<>(); // width, height, #rows, #columns, #folder rows, #folder columns, // iconSize, iconTextSize, #hotseat, #hotseatIconSize, defaultLayoutId. predefinedDeviceProfiles.add(new InvariantDeviceProfile("Super Short Stubby", 255, 300, 2, 3, 2, 3, 3, 48, 13, 3, 48, R.xml.default_workspace_4x4)); predefinedDeviceProfiles.add(new InvariantDeviceProfile("Shorter Stubby", 255, 400, 3, 3, 3, 3, 3, 48, 13, 3, 48, R.xml.default_workspace_4x4)); predefinedDeviceProfiles.add(new InvariantDeviceProfile("Short Stubby", 275, 420, 3, 4, 3, 4, 4, 48, 13, (hasDA ? 4 : 5), 48, (hasDA ? R.xml.default_workspace_4x4_no_all_apps : R.xml.default_workspace_4x4 ))); predefinedDeviceProfiles.add(new InvariantDeviceProfile("Stubby", 255, 450, 3, 4, 3, 4, 4, 48, 13, (hasDA ? 4 : 5), 48, (hasDA ? R.xml.default_workspace_4x4_no_all_apps : R.xml.default_workspace_4x4 ))); predefinedDeviceProfiles.add(new InvariantDeviceProfile("Nexus S", 296, 491.33f, 4, 4, 4, 4, 4, 48, 13,(hasDA ? 4 : 5), 48, (hasDA ? R.xml.default_workspace_4x4_no_all_apps : R.xml.default_workspace_4x4 ))); predefinedDeviceProfiles.add(new InvariantDeviceProfile("Nexus 4", 335, 567, 4, 4, 4, 4, 4, DEFAULT_ICON_SIZE_DP, 13, (hasDA ? 4 : 5), 56, (hasDA ? R.xml.default_workspace_4x4_no_all_apps : R.xml.default_workspace_4x4 ))); predefinedDeviceProfiles.add(new InvariantDeviceProfile("Nexus 5", 359, 567, 4, 4, 4, 4, 4, DEFAULT_ICON_SIZE_DP, 13,(hasDA ? 4 : 5), 56, (hasDA ? R.xml.default_workspace_4x4_no_all_apps : R.xml.default_workspace_4x4 ))); predefinedDeviceProfiles.add(new InvariantDeviceProfile("Large Phone", 406, 694, 5, 5, 4, 4, 4, 64, 14.4f, 5, 56, R.xml.default_workspace_5x5)); // The tablet profile is odd in that the landscape orientation // also includes the nav bar on the side predefinedDeviceProfiles.add(new InvariantDeviceProfile("Nexus 7", 575, 904, 5, 6, 4, 5, 4, 72, 14.4f, 7, 60, R.xml.default_workspace_5x6)); // Larger tablet profiles always have system bars on the top & bottom predefinedDeviceProfiles.add(new InvariantDeviceProfile("Nexus 10", 727, 1207, 5, 6, 4, 5, 4, 76, 14.4f, 7, 64, R.xml.default_workspace_5x6)); predefinedDeviceProfiles.add(new InvariantDeviceProfile("20-inch Tablet", 1527, 2527, 7, 7, 6, 6, 4, 100, 20, 7, 72, R.xml.default_workspace_4x4)); return predefinedDeviceProfiles;}5)記得改下 dw_phone_hotseat.xml 的布局 ，因為Hotseat只有5格了。
四、將所有應用放在第一層
launcher3加載流程:進入 LauncherApplication -> LauncherAppState -> 進行初始化環境(通過傳遞sContext)。進行事件監聽&&初始化一些環境。例如:橫豎屏、當局語言、像素密度、小部件和快捷圖標數據庫操作對象、應用圖標緩存對象、初始化LauncherMode等。在初始化過后，從Launcher的Oncreate方法入手。mModel.startLoader(mWorkspace.getRestorePage());里加載數據 。在加載完成所有快捷方式后將其余為加載完的應用布局在第一層。
1) 成所有快捷方式后將其余為加載完的應用布局在第一層。
Launcher3/src/com/android/launcher3/LauncherModel.java:
LauncherModel$LoaderTask –> run():
public void run() { ... ... // Optimize for end-user experience: if the Launcher is up and // running with the // All Apps interface in the foreground, load All Apps first. Otherwise, load the // workspace first (default). keep_running: { if (DEBUG_LOADERS) Log.d(TAG, "step 1: loading workspace"); loadAndBindWorkspace(); if (mStopped) { LauncherLog.i(TAG, "LoadTask break in the middle, this = " + this); break keep_running; } waitForIdle(); // second step if (DEBUG_LOADERS) Log.d(TAG, "step 2: loading all apps"); loadAndBindAllApps(); //添加 @{ if (LauncherAppState.isDisableAllApps()) { verifyApplications(); } //添加 }@ } // Clear out this reference, otherwise we end up holding it until all of the // callback runnables are done. ... ...}添加verifyApplications():
private void verifyApplications() { final Context context = mApp.getContext(); // Cross reference all the applications in our apps list with items in the workspace ArrayList<ItemInfo> tmpInfos; ArrayList<ItemInfo> added = new ArrayList<ItemInfo>(); synchronized (sBgLock) { for (AppInfo app : mBgAllAppsList.data) { tmpInfos = getItemInfoForComponentName(app.componentName, app.user); if (tmpInfos.isEmpty()) { // We are missing an application icon, so add this to the workspace added.add(app); // This is a rare event, so lets log it Log.e(TAG, "Missing Application on load: " + app); } } } if (!added.isEmpty()) { addAndBindAddedWorkspaceItems(context, added);//7.0 雖然去掉了去抽屜的代碼，但留了這個方法給我們。 }}五、有新應用添加時更新Workspace
當安裝新應用時，我們需要對左面更新，保證安裝的應用添加在第一層上。
Launcher3/src/com/android/launcher3/LauncherModel.java:
LauncherModel$PackageUpdatedTask –> run():
public void run() { if (!mHasLoaderCompletedOnce) { // Loader has not yet run. return; } final Context context = mApp.getContext(); ... ... if (added != null) { // 添加 @{ if(LauncherAppState.isDisableAllApps()){ final ArrayList<ItemInfo> addedInfos = new ArrayList<ItemInfo>(added); addAndBindAddedWorkspaceItems(context, addedInfos); }else{ // 添加 }@ addAppsToAllApps(context, added); } for (AppInfo ai : added) { addedOrUpdatedApps.put(ai.componentName, ai); } } ... ...}六、去掉長按時的刪除選項
長按時，不該有刪除選項 。
DeleteDropTarget.java: 中更改長按時的監聽，開始時直接屏蔽刪除按鈕，后來發現應用自身發出的快捷方式無法刪除 所以做了如下處理。
Launcher3/src/com/android/launcher3/DeleteDropTarget.java –>supportsDrop():
public static boolean supportsDrop(Object info) { //添加 @{ if (LauncherAppState.isDisableAllApps()) { if (info instanceof ShortcutInfo) { ShortcutInfo item = (ShortcutInfo) info; return item.itemType != LauncherSettings.BaseLauncherColumns.ITEM_TYPE_APPLICATION; } return info instanceof LauncherAppWidgetInfo; } //添加 }@ return (info instanceof ShortcutInfo) || (info instanceof LauncherAppWidgetInfo) || (info instanceof FolderInfo);}寫在最后
到此，Launcher3去掉應用抽屜的改動已經完成。還有很多我們需要去美化的，就比如HotSeat布局自適應等。
希望本文所述對大家Android程序設計有所幫助。
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