Add a time period dropdown to the CBD dialog on Android.

chrome/android/java/src/org/chromium/chrome/browser/preferences/SpinnerPreference.java

Index: chrome/android/java/src/org/chromium/chrome/browser/preferences/SpinnerPreference.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/preferences/SpinnerPreference.java b/chrome/android/java/src/org/chromium/chrome/browser/preferences/SpinnerPreference.java
new file mode 100644
index 0000000000000000000000000000000000000000..b7c43b305650ccf2e580d4b907faa8cef6c19ffe
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/preferences/SpinnerPreference.java
@@ -0,0 +1,75 @@
+// Copyright 2014 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.preferences;
+
+import android.content.Context;
+import android.preference.Preference;
+import android.util.AttributeSet;
+import android.view.View;
+import android.widget.AdapterView;
+import android.widget.ArrayAdapter;
+import android.widget.Spinner;
+import android.widget.TextView;
+
+import org.chromium.chrome.R;
+
+/**
+ * A preference that takes value from a specified list of objects, presented as a dropdown.
+ */
+public class SpinnerPreference extends Preference {
+    private Spinner mSpinner;
+    private ArrayAdapter<Object> mAdapter;
+    private int mInitialIndex;

[newt (away), 2016/02/11 23:46:11]

s/Initial/Selected/ ?

[msramek, 2016/02/12 15:10:49]

Done.

This was originally meant to only mean the initial value. But now I noticed that
I kept resetting this value on onBindView(), so I renamed it and update it in
the listener.

+
+    /**
+     * Constructor for inflating from XML.
+     */
+    public SpinnerPreference(Context context, AttributeSet attrs) {
+        super(context, attrs);
+        setLayoutResource(R.layout.preference_spinner);
+    }
+
+    public void setOptions(Object[] options, int initialIndex) {

[newt (away), 2016/02/11 23:46:11]

javadoc for public methods

[msramek, 2016/02/12 15:10:49]

Done.

+        mAdapter = new ArrayAdapter<Object>(
+                getContext(), android.R.layout.simple_spinner_item, options);
+        mAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

[newt (away), 2016/02/11 23:46:11]

Does this work on pre-L devices (i.e. on Holo devices)? You should probably use
the equivalent resources from the support library, assuming it exists. i.e.
"R.layout.simple_spinner_dropdown_item" without the "android." prefix. Same for
simple_spinner_item above.

[msramek, 2016/02/12 15:10:49]

I searched the code for other instances of spinners:

https://code.google.com/p/chromium/codesearch#search/&q=%22setDropDownViewRes...

It seems that we use android.R.layout.simple_spinner_dropdown_item and
android.R.layout.simple_spinner_item almost everywhere, so I'm at least not
decreasing the compatibility. I can try to flash Holo on Monday to see how it
looks like.

[newt (away), 2016/02/12 17:58:04]

I checked on a KitKat device and it looks correct, like the mocks. Also,
simple_spinner_item and simple_spinner_dropdown_item aren't even included in the
support library anyway.

+        mInitialIndex = initialIndex;
+    }
+
+    public Object getSelectedOption() {
+        if (mSpinner == null) return null;
+        return mSpinner.getSelectedItem();
+    }
+
+    @Override
+    protected void onBindView(View view) {
+        super.onBindView(view);
+
+        ((TextView) view.findViewById(R.id.title)).setText(this.getTitle());

[newt (away), 2016/02/11 23:46:11]

remove "this."

[msramek, 2016/02/12 15:10:49]

Done.

+
+        mSpinner = (Spinner) view.findViewById(R.id.spinner);
+        mSpinner.setAdapter(mAdapter);
+        mSpinner.setSelection(mInitialIndex);
+
+        mSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {

[newt (away), 2016/02/11 23:46:11]

Since onBindView() can be called many times, it'd be best to store and reuse the
OnItemSelectedListener rather than create a new once each time.

You could just construct it as a member variable:

  private OnItemSelectedListener mListener = new OnItemSelectedListener() { ...
};

[msramek, 2016/02/12 15:10:49]

Actually, let me split this into onCreateView() with the initialization of
everything that remains constant, and onBindView() with things that could change
(that's mSpinner.setAdapter() and mSpinner.setSelection(), since those can
change through setOptions()).

[newt (away), 2016/02/12 17:58:04]

Even better :)

+            @Override
+            public void onItemSelected(
+                    AdapterView<?> parent, View view, int position, long id) {
+                if (getOnPreferenceChangeListener() != null) {
+                    getOnPreferenceChangeListener().onPreferenceChange(
+                            SpinnerPreference.this, getSelectedOption());
+                }
+            }
+
+            @Override
+            public void onNothingSelected(AdapterView<?> parent) {
+                if (getOnPreferenceChangeListener() != null) {

[newt (away), 2016/02/11 23:46:11]

Does this method get called in practice? The javadoc says "The selection can
disappear for instance when touch is activated". We probably don't want to
update listeners when the user has simply opened the dropdown.

[msramek, 2016/02/12 15:10:49]

Hmm, I wasn't able to reproduce that. Either that doesn't happen on all
versions, or the javadoc is incorrect.

If it does happen under some circumstances, then I agree that we don't want to
update the listeners, so I removed the call. We lose the edge case when someone
passes in an empty array of options, but we can address that at other time if
and when this class is reused elsewhere.

+                    getOnPreferenceChangeListener().onPreferenceChange(
+                            SpinnerPreference.this, null);
+                }
+            }
+        });
+    }
+}