Load widgets in wallpaper app launcher preview

Test: Widgets in wallpaper app launcher preview rendered
Bug: 185306338
Change-Id: I38569d2ff0b64ba55eb188afa42fba4100aae7ff

src/com/android/launcher3/widget/BaseLauncherAppWidgetHostView.java

@@ -0,0 +1,119 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.launcher3.widget;
+
+import android.content.Context;
+import android.graphics.Outline;
+import android.graphics.Rect;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewOutlineProvider;
+import android.widget.RemoteViews;
+
+import androidx.annotation.UiThread;
+
+import com.android.launcher3.R;
+import com.android.launcher3.util.Executors;
+
+/**
+ * Launcher AppWidgetHostView with support for rounded corners and a fallback View.
+ */
+public abstract class BaseLauncherAppWidgetHostView extends NavigableAppWidgetHostView {
+
+    protected final LayoutInflater mInflater;
+
+    private final Rect mEnforcedRectangle = new Rect();
+    private final float mEnforcedCornerRadius;
+    private final ViewOutlineProvider mCornerRadiusEnforcementOutline = new ViewOutlineProvider() {
+        @Override
+        public void getOutline(View view, Outline outline) {
+            if (mEnforcedRectangle.isEmpty() || mEnforcedCornerRadius <= 0) {
+                outline.setEmpty();
+            } else {
+                outline.setRoundRect(mEnforcedRectangle, mEnforcedCornerRadius);
+            }
+        }
+    };
+
+    public BaseLauncherAppWidgetHostView(Context context) {
+        super(context);
+
+        setExecutor(Executors.THREAD_POOL_EXECUTOR);
+
+        mInflater = LayoutInflater.from(context);
+        mEnforcedCornerRadius = RoundedCornerEnforcement.computeEnforcedRadius(getContext());
+    }
+
+    @Override
+    protected View getErrorView() {
+        return mInflater.inflate(R.layout.appwidget_error, this, false);
+    }
+
+    /**
+     * Fall back to error layout instead of showing widget.
+     */
+    public void switchToErrorView() {
+        // Update the widget with 0 Layout id, to reset the view to error view.
+        updateAppWidget(new RemoteViews(getAppWidgetInfo().provider.getPackageName(), 0));
+    }
+
+    @Override
+    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
+        try {
+            super.onLayout(changed, left, top, right, bottom);
+        } catch (final RuntimeException e) {
+            post(this::switchToErrorView);
+        }
+
+        enforceRoundedCorners();
+    }
+
+    @UiThread
+    private void resetRoundedCorners() {
+        setOutlineProvider(ViewOutlineProvider.BACKGROUND);
+        setClipToOutline(false);
+    }
+
+    @UiThread
+    private void enforceRoundedCorners() {
+        if (mEnforcedCornerRadius <= 0 || !RoundedCornerEnforcement.isRoundedCornerEnabled()) {
+            resetRoundedCorners();
+            return;
+        }
+        View background = RoundedCornerEnforcement.findBackground(this);
+        if (background == null
+                || RoundedCornerEnforcement.hasAppWidgetOptedOut(this, background)) {
+            resetRoundedCorners();
+            return;
+        }
+        RoundedCornerEnforcement.computeRoundedRectangle(this,
+                background,
+                mEnforcedRectangle);
+        setOutlineProvider(mCornerRadiusEnforcementOutline);
+        setClipToOutline(true);
+    }
+
+    /** Returns the corner radius currently enforced, in pixels. */
+    public float getEnforcedCornerRadius() {
+        return mEnforcedCornerRadius;
+    }
+
+    /** Returns true if the corner radius are enforced for this App Widget. */
+    public boolean hasEnforcedCornerRadius() {
+        return getClipToOutline();
+    }
+}