原：Android8.1、9.0主菜单背景透明修改方案

如果你不想改为全透明，只想调节透明度

1.packages\apps\Launcher3\res\values\styles.xml
主题一：

<style name="BaseLauncherThemeWithCustomAttrs" parent="@style/BaseLauncherTheme">
    <item name="allAppsScrimColor">#CCFFFFFF</item>

主题二：

<style name="LauncherThemeDark" parent="@style/LauncherTheme">
    <item name="allAppsScrimColor">#7A212121</item>

其中#号后面的两位数字“CC”和“7A”为透明度（00～FF），可以根据需求修改，全透明为00

2. packages\apps\Launcher3\res\values\congfig.xml

<integer name="extracted_color_gradient_alpha">153</integer>

取值范围为0～255

具体修改原因这里不多做介绍，“Read The Fucking Source Code!”

主菜单全透明比较完善的方案基于原生Launcher3，需要的拿走

SampleCode.diff

diff --git a/res/layout/all_apps_icon.xml b/res/layout/all_apps_icon.xml
index 79fb6126a..e8fbf71f3 100644
--- a/res/layout/all_apps_icon.xml
+++ b/res/layout/all_apps_icon.xml
@@ -16,7 +16,7 @@
 <com.android.launcher3.BubbleTextView
     xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:launcher="http://schemas.android.com/apk/res-auto"
-    style="@style/BaseIcon"
+    style="@style/BaseIcon.Workspace"
     android:id="@+id/icon"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
diff --git a/res/layout/search_container_all_apps.xml b/res/layout/search_container_all_apps.xml
index f4ccde1eb..818f98490 100644
--- a/res/layout/search_container_all_apps.xml
+++ b/res/layout/search_container_all_apps.xml
@@ -50,8 +50,8 @@
         android:layout_marginLeft="@dimen/all_apps_search_bar_max_padding"
         android:layout_marginRight="@dimen/all_apps_search_bar_max_padding"
         android:singleLine="true"
-        android:textColor="?android:attr/textColorSecondary"
-        android:textColorHint="@drawable/all_apps_search_hint"
+        android:textColor="?attr/workspaceTextColor"
+        android:textColorHint="?attr/workspaceTextColor"
         android:textSize="16sp" />
 
     <!-- This needs to be a container with a view, to simulate a scrolling effect for the header.
@@ -66,6 +66,6 @@
         <View
             android:layout_width="match_parent"
             android:layout_height="1dp"
-            android:background="@drawable/all_apps_search_divider"/>
+            android:background="?attr/workspaceTextColor"/>
     </FrameLayout>
 </com.android.launcher3.allapps.search.AppsSearchContainerLayout>
\ No newline at end of file
diff --git a/res/values/styles.xml b/res/values/styles.xml
index c4ff9bdf0..ea0dd01b0 100644
--- a/res/values/styles.xml
+++ b/res/values/styles.xml
@@ -114,7 +114,7 @@
         <item name="android:gravity">center_horizontal</item>
         <item name="android:singleLine">true</item>
         <item name="android:ellipsize">marquee</item>
-        <item name="android:textColor">?android:attr/textColorSecondary</item>
+        <item name="android:textColor">?attr/workspaceTextColor</item>
         <item name="android:fontFamily">sans-serif-condensed</item>
 
         <!-- No shadows in the base theme -->
diff --git a/src/com/android/launcher3/allapps/AllAppsTransitionController.java b/src/com/android/launcher3/allapps/AllAppsTransitionController.java
index 743b16ef1..d4dd349de 100644
--- a/src/com/android/launcher3/allapps/AllAppsTransitionController.java
+++ b/src/com/android/launcher3/allapps/AllAppsTransitionController.java
@@ -289,7 +289,7 @@ public class AllAppsTransitionController implements TouchController, SwipeDetect
         boolean forceChange = FeatureFlags.LAUNCHER3_GRADIENT_ALL_APPS ?
                 shift <= mShiftRange / 4 :
                 shift <= mStatusBarHeight / 2;
-        if (forceChange) {
+        if (false) {
             mLauncher.getSystemUiController().updateUiState(
                     SystemUiController.UI_STATE_ALL_APPS, !mIsDarkTheme);
         } else {
diff --git a/src/com/android/launcher3/graphics/GradientView.java b/src/com/android/launcher3/graphics/GradientView.java
index 5455b43ec..abc11bef9 100644
--- a/src/com/android/launcher3/graphics/GradientView.java
+++ b/src/com/android/launcher3/graphics/GradientView.java
@@ -160,24 +160,24 @@ public class GradientView extends View implements WallpaperColorInfo.OnChangeLis
 
     @Override
     protected void onDraw(Canvas canvas) {
-        Paint paint = mShowScrim ? mPaintWithScrim : mPaintNoScrim;
-
-        float head = 0.29f;
-        float linearProgress = head + (mProgress * (1f - head));
-        float startMaskY = (1f - linearProgress) * mHeight - mMaskHeight * linearProgress;
-        float interpolatedAlpha = (255 - mAlphaStart) * mAccelerator.getInterpolation(mProgress);
-        paint.setAlpha((int) (mAlphaStart + interpolatedAlpha));
-        float div = (float) Math.floor(startMaskY + mMaskHeight);
-        mAlphaMaskRect.set(0, startMaskY, mWidth, div);
-        mFinalMaskRect.set(0, div, mWidth, mHeight);
-        canvas.drawBitmap(mAlphaGradientMask, null, mAlphaMaskRect, paint);
-        canvas.drawRect(mFinalMaskRect, paint);
-
-        if (DEBUG) {
-            mDebugPaint.setColor(0xFF00FF00);
-            canvas.drawLine(0, startMaskY, mWidth, startMaskY, mDebugPaint);
-            canvas.drawLine(0, startMaskY + mMaskHeight, mWidth, startMaskY + mMaskHeight, mDebugPaint);
-        }
+//        Paint paint = mShowScrim ? mPaintWithScrim : mPaintNoScrim;
+//
+//        float head = 0.29f;
+//        float linearProgress = head + (mProgress * (1f - head));
+//        float startMaskY = (1f - linearProgress) * mHeight - mMaskHeight * linearProgress;
+//        float interpolatedAlpha = (255 - mAlphaStart) * mAccelerator.getInterpolation(mProgress);
+//        paint.setAlpha((int) (mAlphaStart + interpolatedAlpha));
+//        float div = (float) Math.floor(startMaskY + mMaskHeight);
+//        mAlphaMaskRect.set(0, startMaskY, mWidth, div);
+//        mFinalMaskRect.set(0, div, mWidth, mHeight);
+//        canvas.drawBitmap(mAlphaGradientMask, null, mAlphaMaskRect, paint);
+//        canvas.drawRect(mFinalMaskRect, paint);
+//
+//        if (DEBUG) {
+//            mDebugPaint.setColor(0xFF00FF00);
+//            canvas.drawLine(0, startMaskY, mWidth, startMaskY, mDebugPaint);
+//            canvas.drawLine(0, startMaskY + mMaskHeight, mWidth, startMaskY + mMaskHeight, mDebugPaint);
+//        }
     }
 
     public Bitmap createDitheredAlphaMask() {