🔍 Introduce default search engine dialog

chrome/android/java/src/org/chromium/chrome/browser/widget/PromoDialogLayout.java

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser.widget;
 
 import android.content.Context;
 import android.util.AttributeSet;
 import android.view.ViewGroup;
+import android.view.ViewStub;
 import android.widget.ImageView;
 import android.widget.LinearLayout;
 import android.widget.TextView;
 
+import org.chromium.base.ApiCompatibilityUtils;
 import org.chromium.chrome.R;
+import org.chromium.chrome.browser.infobar.InfoBarControlLayout;
 import org.chromium.chrome.browser.widget.PromoDialog.DialogParams;
 
 /**
- * View that handles orientation changes for the promo dialogs. When the width is greater than the
- * height, the promo content switches from vertical to horizontal and moves the illustration from
- * the top of the text to the side of the text.
+ * Lays out a promo dialog that is shown when Clank starts up.
+ *
+ * Because of the versatility of dialog content and screen sizes, this layout exhibits a bunch of
+ * specific behaviors (see go/snowflake-dialogs for details):

[gone, 2017/04/26 05:52:36]

Clarified why this class is a bit messy by expanding the comment, but I'm
hesitant to link to an internal design doc that can't be viewed externally. 
Thoughts?

+ *
+ * + It hides controls when their resources are not specified by the {@link DialogParams}.
+ *   The only two required components are the header text and the primary button label.
+ *
+ * + When the width is greater than the height, the promo content switches from vertical to
+ *   horizontal and moves the illustration from the top of the text to the side of the text.
+ *
+ * + The buttons are always locked to the bottom of the dialog and stack when there isn't enough
+ *   room to display them on one row.
+ *
+ * + If there is no promo illustration, the header text becomes locked to the top of the dialog and
+ *   doesn't scroll away.
  */
 public final class PromoDialogLayout extends BoundedLinearLayout {
+    /** Content in the dialog that will flip orientation when the screen is wide. */
+    private LinearLayout mFlippableContent;
+
     /** Content in the dialog that can be scrolled. */
     private LinearLayout mScrollableContent;
 
     /** Illustration that teases the thing being promoted. */
     private ImageView mIllustrationView;
 
     /** View containing the header of the promo. */
     private TextView mHeaderView;
 
+    /** View containing the header of the promo. */
+    private TextView mFooterView;
+
     /** View containing text explaining the promo. */
     private TextView mSubheaderView;
 
     /** Paramters used to build the promo. */
     private DialogParams mParams;
 
     public PromoDialogLayout(Context context, AttributeSet attrs) {
         super(context, attrs);
     }
 
     @Override
     public void onFinishInflate() {
-        mScrollableContent = (LinearLayout) findViewById(R.id.promo_content);
+        mFlippableContent = (LinearLayout) findViewById(R.id.full_promo_content);
+        mScrollableContent = (LinearLayout) findViewById(R.id.scrollable_promo_content);
         mIllustrationView = (ImageView) findViewById(R.id.illustration);
         mHeaderView = (TextView) findViewById(R.id.header);
         mSubheaderView = (TextView) findViewById(R.id.subheader);
 
         super.onFinishInflate();
     }
 
     /** Initializes the dialog contents using the given params.  Should only be called once. */
     void initialize(DialogParams params) {
         assert mParams == null && params != null;
+        assert params.headerStringResource != 0;
+        assert params.primaryButtonStringResource != 0;
         mParams = params;
 
         if (mParams.drawableResource == 0) {
+            // Dialogs with no illustration make the header stay visible at all times instead of
+            // scrolling off on small screens.
             ((ViewGroup) mIllustrationView.getParent()).removeView(mIllustrationView);
+            ((ViewGroup) mHeaderView.getParent()).removeView(mHeaderView);
+            addView(mHeaderView, 0);
+
+            // The margins only apply here (after it moves to the root) because the scroll layout it
+            // is normally in has implicit padding.
+            int marginSize =
+                    getContext().getResources().getDimensionPixelSize(R.dimen.dialog_header_margin);
+            ApiCompatibilityUtils.setMarginStart(
+                    (MarginLayoutParams) mHeaderView.getLayoutParams(), marginSize);
+            ApiCompatibilityUtils.setMarginEnd(
+                    (MarginLayoutParams) mHeaderView.getLayoutParams(), marginSize);
         } else {
             mIllustrationView.setImageResource(mParams.drawableResource);
         }
 
-        // TODO(dfalcantara): Lock the title in place, if requested by the DialogParams.
+        // Create the header.
         mHeaderView.setText(mParams.headerStringResource);
 
+        // Set up the subheader text.
         if (mParams.subheaderStringResource == 0) {
             ((ViewGroup) mSubheaderView.getParent()).removeView(mSubheaderView);
         } else {
             mSubheaderView.setText(mParams.subheaderStringResource);
         }
 
+        // Create the footer.
+        ViewStub footerStub = (ViewStub) findViewById(R.id.footer_stub);
+        if (mParams.footerStringResource == 0) {
+            ((ViewGroup) footerStub.getParent()).removeView(footerStub);
+        } else {
+            mFooterView = (TextView) footerStub.inflate();
+            mFooterView.setText(mParams.footerStringResource);
+        }
+
+        // Create the buttons.
         DualControlLayout buttonBar = (DualControlLayout) findViewById(R.id.button_bar);
-        if (mParams.primaryButtonStringResource != 0) {
-            String primaryString = getResources().getString(mParams.primaryButtonStringResource);
+        String primaryString = getResources().getString(mParams.primaryButtonStringResource);
+        buttonBar.addView(
+                DualControlLayout.createButtonForLayout(getContext(), true, primaryString, null));
+
+        if (mParams.secondaryButtonStringResource != 0) {
+            String secondaryString =
+                    getResources().getString(mParams.secondaryButtonStringResource);
             buttonBar.addView(DualControlLayout.createButtonForLayout(
-                    getContext(), true, primaryString, null));
-
-            if (mParams.secondaryButtonStringResource != 0) {
-                String secondaryString =
-                        getResources().getString(mParams.secondaryButtonStringResource);
-                buttonBar.addView(DualControlLayout.createButtonForLayout(
-                        getContext(), false, secondaryString, null));
-            }
-        } else {
-            assert mParams.secondaryButtonStringResource == 0;
+                    getContext(), false, secondaryString, null));
         }
     }
 
     @Override
     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
         int availableWidth = MeasureSpec.getSize(widthMeasureSpec);
         int availableHeight = MeasureSpec.getSize(heightMeasureSpec);
 
         if (availableWidth > availableHeight * 1.5) {
-            mScrollableContent.setOrientation(LinearLayout.HORIZONTAL);
+            mFlippableContent.setOrientation(LinearLayout.HORIZONTAL);
         } else {
-            mScrollableContent.setOrientation(LinearLayout.VERTICAL);
+            mFlippableContent.setOrientation(LinearLayout.VERTICAL);
         }
 
         super.onMeasure(widthMeasureSpec, heightMeasureSpec);
     }
+
+    /** Adds a standardized set of controls to the layout. */
+    InfoBarControlLayout addControlLayout() {
+        InfoBarControlLayout layout = new InfoBarControlLayout(getContext());
+        mScrollableContent.addView(
+                layout, new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT));
+        return layout;
+    }
 }