❄ Split off RadioButtonLayout from InfoBarControls

chrome/android/java/src/org/chromium/chrome/browser/widget/RadioButtonLayout.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.support.annotation.Nullable;
+import android.util.AttributeSet;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.widget.RadioButton;
+import android.widget.RadioGroup;
+
+import org.chromium.chrome.R;
+
+import java.util.List;
+
+/**
+ * Manages a group of exclusive RadioButtons, automatically inserting a margin in between the rows
+ * to prevent them from squishing together.
+ *
+ * -------------------------------------------------
+ * | O | MESSAGE #1                                |
+ * | O | MESSAGE #N                                |
+ * -------------------------------------------------
+ */
+public final class RadioButtonLayout extends RadioGroup {
+    public static final int INVALID_INDEX = -1;
+
+    private final int mMarginBetweenRows;
+
+    public RadioButtonLayout(Context context) {
+        this(context, null);
+    }
+
+    public RadioButtonLayout(Context context, AttributeSet attrs) {
+        super(context, attrs);
+        mMarginBetweenRows = context.getResources().getDimensionPixelSize(
+                R.dimen.infobar_control_margin_between_rows);
+    }
+
+    /**
+     * Adds a set of standard radio buttons for the given messages and adds them to the layout.
+     *
+     * @param messages      Messages to display for the options.
+     * @param tags          Optional list of tags to attach to the buttons.
+     */
+    public void addOptions(List<CharSequence> messages, @Nullable List<?> tags) {
+        if (tags != null) assert tags.size() == messages.size();
+
+        for (int i = 0; i < messages.size(); i++) {
+            RadioButton button = (RadioButton) LayoutInflater.from(getContext())
+                                         .inflate(R.layout.radio_button_layout_element, null);
+            button.setText(messages.get(i));
+            if (tags != null) button.setTag(tags.get(i));
+
+            addView(button, new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT));
+        }
+
+        updateMargins();
+    }
+
+    /**
+     * Marks a RadioButton child as being checked.
+     *
+     * Android doesn't provide a way of generating View IDs on the fly before API level 17, so this

[Theresa, 2017/05/01 15:21:09]

Android's method of generating View IDs could be copied into
ApiCompatibilityUtils. We generate view IDs for LayerTitleCache currently using
a very similar method.

This is okay, too, though if you'd prefer to use indexes over view ID's.

[gone, 2017/05/01 15:29:30]

Figured that kind of logic be used elsewhere, but it's used in at least a few
places now.  You think it's alright to save that for later?

[Theresa, 2017/05/01 15:43:08]

Yes, fine to save for later. I think that we only generate view IDs in
LayerTitleCache -- if we ever generate in more than one place then we need to
centralize the logic.

+     * function requires passing in the child's index.  Passing in {@link #INVALID_INDEX} marks them
+     * all as de-selected.
+     *
+     * @param childIndex Index of the child to select.
+     */
+    public void selectChildAtIndex(int childIndex) {
+        int childCount = getChildCount();
+        for (int i = 0; i < childCount; i++) {
+            RadioButton child = (RadioButton) getChildAt(i);
+            child.setChecked(i == childIndex);
+        }
+    }
+
+    /** Sets margins between each of the radio buttons. */
+    private void updateMargins() {
+        int childCount = getChildCount();
+        for (int i = 0; i < childCount; i++) {
+            View child = getChildAt(i);
+            int margin = (i < childCount - 1) ? mMarginBetweenRows : 0;
+            ((MarginLayoutParams) child.getLayoutParams()).bottomMargin = margin;

[Theresa, 2017/05/01 15:21:09]

Is it possible to fold this into the loop in addOptions()?

[gone, 2017/05/01 15:29:30]

I had it there originally, but that doesn't work if (for some reason) someone
decides to add more options to the list one-by-one (see
RadioButtonLayoutTest#testMargins()).  If I called it setOptions() it'd work,
though.  WDYT?

[Theresa, 2017/05/01 15:43:08]

I think updateMargins() is a fine name. I wasn't thinking about that case, but
it makes sense.

+        }
+    }
+}