Android 12 Launcher3 去掉Hotseat

1.概述

   在12.0 产品定制化开发中 由产品需求Launcher3 页面布局的原因，要求Launcher3 需要去掉Hotseat 不显示Hotseat下面几个图标，而做满屏app的显示，从而达到美观的效果，下面就来分析去掉Hotseat从而实现这个功能

2.Launcher3 去掉Hotseat的核心类

packages/apps/Launcher3/res/layout/launcher.xml
packages/apps/Launcher3/src/com/android/launcher3/DeviceProfile.java

3.Launcher3 去掉Hotseat的核心功能分析和实现

        在Launcher3中主页面就是launcher.xml只布局，hotseat布局也在这里面，所以隐藏hotseat可以从这里先看launcher.xml的布局。
首先看下launcher.xml的布局

3.1 launcher.xml  hotseat布局

<com.android.launcher3.LauncherRootView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:launcher="http://schemas.android.com/apk/res-auto"
android:id="@+id/launcher"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true">
<com.android.launcher3.dragndrop.DragLayerandroid:id="@+id/drag_layer"android:layout_width="match_parent"android:layout_height="match_parent"android:clipChildren="false"android:clipToPadding="false"android:importantForAccessibility="no"><!-- The workspace contains 5 screens of cells --><!-- DO NOT CHANGE THE ID --><com.android.launcher3.Workspaceandroid:id="@+id/workspace"android:layout_width="match_parent"android:layout_height="match_parent"android:layout_gravity="center"android:theme="@style/HomeScreenElementTheme"launcher:pageIndicator="@+id/page_indicator" /><include layout="@layout/memoryinfo_ext" /><!-- DO NOT CHANGE THE ID --><includeandroid:id="@+id/hotseat"layout="@layout/hotseat" /><includeandroid:id="@+id/overview_panel"layout="@layout/overview_panel"android:visibility="gone" /><!-- Keep these behind the workspace so that they are not visible whenwe go into AllApps --><com.sprd.ext.pageindicators.WorkspacePageIndicatorLineandroid:id="@+id/page_indicator"android:layout_width="match_parent"android:layout_height="@dimen/vertical_drag_handle_size"android:layout_gravity="bottom"android:theme="@style/HomeScreenElementTheme" /><includeandroid:id="@+id/page_indicator_customize"layout="@layout/page_indicator_customize" /><includeandroid:id="@+id/drop_target_bar"layout="@layout/drop_target_bar" /><includeandroid:id="@+id/scrim_view"layout="@layout/scrim_view" /><includeandroid:id="@+id/apps_view"layout="@layout/all_apps"android:layout_width="match_parent"android:layout_height="match_parent" /></com.android.launcher3.dragndrop.DragLayer></com.android.launcher3.LauncherRootView>

从布局中可以看到android:id="@+id/hotseat"就是hotseat布局，所以隐藏hotseat就是需要设置属性为gone。

<includeandroid:id="@+id/hotseat"layout="@layout/hotseat"android:visibility="gone" />

3.2 DeviceProfile.java 关于hotseat高度的修改

public DeviceProfile(Context context, InvariantDeviceProfile inv,
Point minSize, Point maxSize,
int width, int height, boolean isLandscape, boolean isMultiWindowMode) {this.inv = inv;this.isLandscape = isLandscape;this.isMultiWindowMode = isMultiWindowMode;// Determine sizes.widthPx = width;heightPx = height;if (isLandscape) {availableWidthPx = maxSize.x;availableHeightPx = minSize.y;} else {availableWidthPx = minSize.x;availableHeightPx = maxSize.y;}Resources res = context.getResources();DisplayMetrics dm = res.getDisplayMetrics();// Constants from resourcesisTablet = res.getBoolean(R.bool.is_tablet);isLargeTablet = res.getBoolean(R.bool.is_large_tablet);isPhone = !isTablet && !isLargeTablet;aspectRatio = ((float) Math.max(widthPx, heightPx)) / Math.min(widthPx, heightPx);boolean isTallDevice = Float.compare(aspectRatio, TALL_DEVICE_ASPECT_RATIO_THRESHOLD) >= 0;// Some more constantstransposeLayoutWithOrientation =res.getBoolean(R.bool.hotseat_transpose_layout_with_orientation);context = getContext(context, isVerticalBarLayout()? Configuration.ORIENTATION_LANDSCAPE: Configuration.ORIENTATION_PORTRAIT);res = context.getResources();edgeMarginPx = res.getDimensionPixelSize(R.dimen.dynamic_grid_edge_margin);desiredWorkspaceLeftRightMarginPx = isVerticalBarLayout() ? 0 : edgeMarginPx;int cellLayoutPaddingLeftRightMultiplier = !isVerticalBarLayout() && isTablet? PORTRAIT_TABLET_LEFT_RIGHT_PADDING_MULTIPLIER : 1;int cellLayoutPadding = res.getDimensionPixelSize(R.dimen.dynamic_grid_cell_layout_padding);if (isLandscape) {cellLayoutPaddingLeftRightPx = 0;cellLayoutBottomPaddingPx = cellLayoutPadding;} else {cellLayoutPaddingLeftRightPx = cellLayoutPaddingLeftRightMultiplier * cellLayoutPadding;cellLayoutBottomPaddingPx = 0;}verticalDragHandleSizePx = res.getDimensionPixelSize(R.dimen.vertical_drag_handle_size);verticalDragHandleOverlapWorkspace =res.getDimensionPixelSize(R.dimen.vertical_drag_handle_overlap_workspace);IconLabelController ilc = LauncherAppMonitor.getInstance(context).getIconLabelController();maxIconLabelLines = ilc != null ?ilc.getIconLabelLine() : IconLabelController.MIN_ICON_LABEL_LINE;iconDrawablePaddingOriginalPx =res.getDimensionPixelSize(R.dimen.dynamic_grid_icon_drawable_padding);dropTargetBarSizePx = res.getDimensionPixelSize(R.dimen.dynamic_grid_drop_target_size);workspaceSpringLoadedBottomSpace =res.getDimensionPixelSize(R.dimen.dynamic_grid_min_spring_loaded_space);workspaceCellPaddingXPx = res.getDimensionPixelSize(R.dimen.dynamic_grid_cell_padding_x);hotseatBarTopPaddingPx =res.getDimensionPixelSize(R.dimen.dynamic_grid_hotseat_top_padding);hotseatBarBottomPaddingPx = (isTallDevice ? 0: res.getDimensionPixelSize(R.dimen.dynamic_grid_hotseat_bottom_non_tall_padding))+ res.getDimensionPixelSize(R.dimen.dynamic_grid_hotseat_bottom_padding);hotseatBarSidePaddingEndPx =res.getDimensionPixelSize(R.dimen.dynamic_grid_hotseat_side_padding);// Add a bit of space between nav bar and hotseat in vertical bar layout.hotseatBarSidePaddingStartPx = isVerticalBarLayout() ? verticalDragHandleSizePx : 0;hotseatBarSizePx = ResourceUtils.pxFromDp(inv.iconSize, dm) + (isVerticalBarLayout()? (hotseatBarSidePaddingStartPx + hotseatBarSidePaddingEndPx): (res.getDimensionPixelSize(R.dimen.dynamic_grid_hotseat_extra_vertical_size)+ hotseatBarTopPaddingPx + hotseatBarBottomPaddingPx));....}

在DeviceProile构造函数中的hotseatBarSizePx 就是设置的导航栏高度，在这里构建hotseat布局的时候，可以通过设置这个高度了布后hotseatBarSizePx就是hotseat的高度
直接设为0即可
修改如下:

hotseatBarSizePx = 0/*ResourceUtils.pxFromDp(inv.iconSize, dm) + (isVerticalBarLayout()? (hotseatBarSidePaddingStartPx + hotseatBarSidePaddingEndPx): (res.getDimensionPixelSize(R.dimen.dynamic_grid_hotseat_extra_vertical_size)+ hotseatBarTopPaddingPx + hotseatBarBottomPaddingPx))*/;