[Payments] Preview available payment options when no option is selected

chrome/android/java/src/org/chromium/chrome/browser/payments/ui/SectionUiUtils.java

Index: chrome/android/java/src/org/chromium/chrome/browser/payments/ui/SectionUiUtils.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/payments/ui/SectionUiUtils.java b/chrome/android/java/src/org/chromium/chrome/browser/payments/ui/SectionUiUtils.java
new file mode 100644
index 0000000000000000000000000000000000000000..2980cc7095ab37fa98a42c5111e8a0b64da5d376
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/payments/ui/SectionUiUtils.java
@@ -0,0 +1,104 @@
+// 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.payments.ui;
+
+import android.content.Context;
+import android.text.Layout;
+import android.text.TextPaint;
+import android.view.View;
+import android.widget.TextView;
+
+import org.chromium.chrome.R;
+
+import javax.annotation.Nullable;
+
+/**
+ * Utility functions for PaymentRequestSection.
+ * This class is not supposed to be instantiated.
+ */
+public class SectionUiUtils {
+    /** Avoid instantiation by accident. */
+    private SectionUiUtils() {}
+
+    /**
+     * Show the section summary in the view in a single line. This is called when there is no
+     * selected item in the section.
+     *
+     * @param context The context.
+     * @param section The section to summarize.
+     * @param view    The view to display the summary.
+     */
+    public static void showSectionSummaryInTextViewInSingeLine(
+            final Context context, final SectionInformation section, final TextView view) {
+        int optionCount = section.getSize();
+        if (optionCount == 0) {
+            view.setText(null);
+            return;
+        }
+
+        // Listen for layout event to check whether the string can be fit in a single line and
+        // manually elide the string in the middle if necessary.
+        if (view.getLayout() == null && optionCount > 1) {
+            view.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
+                @Override
+                public void onLayoutChange(View v, int left, int top, int right, int bottom,
+                        int oldLeft, int oldTop, int oldRight, int oldBottom) {
+                    if (section.getSelectedItem() != null) {
+                        view.removeOnLayoutChangeListener(this);
+                        return;
+                    }
+
+                    Layout layout = view.getLayout();
+                    if (layout.getEllipsisCount(0) > 0) {
+                        String summary = getSectionSummaryForPreviewInASingleLine(
+                                context, section, layout, view.getPaint());
+                        view.setText(summary);
+                    }
+                }
+            });
+        }
+
+        String summary = SectionUiUtils.getSectionSummaryForPreviewInASingleLine(
+                context, section, view.getLayout(), view.getPaint());
+        view.setText(summary);
+    }
+
+    private static String getSectionSummaryForPreviewInASingleLine(Context context,
+            SectionInformation section, @Nullable Layout layout, @Nullable TextPaint paint) {
+        int optionCount = section.getSize();
+        assert optionCount != 0;
+
+        // If there is only one option in the section, return the summary of that option in a single
+        // line, let the TextView automatically elide it at the end.
+        // If there are more than one options in the section, then the returned string pattern is
+        // "<summary of the first option>... and N more". N+1 is the total number of options in the
+        // section. If layout or paint is null, return the summary string without shrink. Otherwise,
+        // check and shrink "<summary of the first option>" so as to make the entire summary string
+        // fits in a single line.
+        PaymentOption option = section.getItem(0);
+        String labelSeparator = context.getString(R.string.autofill_address_summary_separator);
+        String optionSummary = option.getPreviewString(labelSeparator, -1);
+        int moreOptionCount = optionCount - 1;
+        if (moreOptionCount == 0) return optionSummary;
+
+        // Append string to indicate how many more options in the given section.
+        int resId = section.getPreviewStringResourceId();
+        assert resId > 0;
+        String summary = context.getResources().getQuantityString(
+                resId, moreOptionCount, optionSummary, moreOptionCount);
+        if (paint == null || layout == null) {
+            return summary;
+        }
+
+        int ellipsizedWidth = layout.getEllipsizedWidth();
+        while (Layout.getDesiredWidth(summary, paint) > ellipsizedWidth) {
+            optionSummary = option.getPreviewString(labelSeparator, optionSummary.length());
+            summary = context.getResources().getQuantityString(
+                    resId, moreOptionCount, optionSummary, moreOptionCount);
+        }
+
+        return summary;
+    }
+}