Turn Autofill country text input into a Spinner.

chrome/android/java/src/org/chromium/chrome/browser/autofill/CountryAdapter.java

Index: chrome/android/java/src/org/chromium/chrome/browser/autofill/CountryAdapter.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/autofill/CountryAdapter.java b/chrome/android/java/src/org/chromium/chrome/browser/autofill/CountryAdapter.java
new file mode 100644
index 0000000000000000000000000000000000000000..8b8bda81f96362de763f45cae5998ed2e612eddf
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/autofill/CountryAdapter.java
@@ -0,0 +1,130 @@
+// 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.autofill;
+
+import android.database.DataSetObserver;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.SpinnerAdapter;
+import android.widget.TextView;
+
+import org.chromium.base.JNINamespace;
+import org.chromium.base.ThreadUtils;
+import org.chromium.chrome.R;
+
+/**
+ * Android wrapper for CountryComboboxModel.
+ *
+ * Only useable from the UI layer. Used in the Android settings UI.
+ *
+ * See chrome/browser/ui/android/autofill/country_adapter_android.h for more details.
+ */
+@JNINamespace("autofill")
+public class CountryAdapter implements SpinnerAdapter {
+    LayoutInflater mInflater;

[aurimas (slooooooooow), 2014/08/01 15:18:21]

Can this be private?

[Evan Stade, 2014/08/01 18:59:23]

yes

+
+    @Override
+    public int getCount() {
+        return nativeGetItemCount(mCountryAdapterAndroid);
+    }
+
+    @Override
+    public Object getItem(int position) {
+        return nativeGetCountryCodeAt(mCountryAdapterAndroid, position);
+    }
+
+    @Override
+    public long getItemId(int position) {
+        return position;
+    }
+
+    @Override
+    public int getItemViewType(int position) {
+        return 0;
+    }
+
+    @Override
+    public View getView(int position, View convertView, ViewGroup parent) {
+        TextView textView = (TextView) convertView;
+        if (textView == null) {
+            textView = (TextView) mInflater.inflate(R.layout.country_text, parent, false);
+        }
+
+        textView.setText(nativeGetCountryNameAt(mCountryAdapterAndroid, position));
+        return textView;
+    }
+
+    @Override
+    public boolean hasStableIds() {
+        return true;
+    }
+
+    @Override
+    public int getViewTypeCount() {
+        return 1;
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return false;
+    }
+
+    @Override
+    public void registerDataSetObserver(DataSetObserver observer) {}
+
+    @Override
+    public void unregisterDataSetObserver(DataSetObserver observer) {}
+
+    @Override
+    public View getDropDownView(int position, View convertView, ViewGroup parent) {
+        TextView textView = (TextView) convertView;
+        if (textView == null) {
+            textView = (TextView) mInflater.inflate(R.layout.country_item, parent, false);
+        }
+
+        textView.setText(nativeGetCountryNameAt(mCountryAdapterAndroid, position));
+        return textView;
+    }
+
+    /**
+     * Sets the LayoutInflater used for making views.
+     */
+    public void setLayoutInflater(LayoutInflater inflater) {
+        mInflater = inflater;
+    }
+
+    /**
+     * Gets the index in the model for the given country code.
+     */
+    public int getIndexForCountryCode(String countryCode) {
+        for (int i = 0; i < getCount(); i++) {
+            if (countryCode.equals(getItem(i)))

[aurimas (slooooooooow), 2014/08/01 15:18:21]

Doesn't this result in getCount() of JNI calls? JNI calls are fairly expensive
and we try to avoid call it unnecessarily. Can we get around that either passing
in the country codes in the constructor of this class or doing all this checking
in c++?

[Evan Stade, 2014/08/01 18:59:23]

I was wondering about that. I figured JNI wasn't expensive because
PersonalDataManager calls nativeGetProfileByIndex repeatedly instead of having a
nativeGetProfilesByIndex that's called just once. I will rejigger this class to
reduce the number of native calls.

+                return i;

[aurimas (slooooooooow), 2014/08/01 15:18:21]

move "return i;" to the same line with if statement. In java one line statements
either go on the same like with the if statement or you need to put curly braces
around it.

[Evan Stade, 2014/08/01 18:59:23]

Acknowledged.

+        }
+        return 0;
+    }
+
+    private static CountryAdapter sAdapter;
+
+    public static CountryAdapter getInstance() {

[aurimas (slooooooooow), 2014/08/01 15:18:21]

Can you explain why are we using a static instance of the Country adapter
instead of just returning the real object? The static variable does not seem to
be unset anywhere either.

[Evan Stade, 2014/08/01 18:59:23]

What do you mean by the "real object"?

The reason we're using a singleton is because we don't actually need more than
one. There is no state that would vary from instance to instance. This follows
the example of PersonalDataManager.

[aurimas (slooooooooow), 2014/08/04 15:37:03]

The way you are creating the CountryAdapter will make it stick around and use up
memory until chrome is killed since it is a static member variable.

[Evan Stade, 2014/08/04 20:36:04]

That is how singletons tend to work. One benefit is that we avoid repeated
initialization.

+        ThreadUtils.assertOnUiThread();
+        if (sAdapter == null) {
+          sAdapter = new CountryAdapter();
+        }
+        return sAdapter;
+    }
+
+    private final long mCountryAdapterAndroid;

[aurimas (slooooooooow), 2014/08/01 15:18:21]

In java we put all member variable definitions to the top of the class.

[Evan Stade, 2014/08/01 18:59:22]

OK. (I was basically copying PersonalDataManager.)

+
+    private CountryAdapter() {
+        mCountryAdapterAndroid = nativeInit();
+    }
+
+    private native long nativeInit();
+    private native int nativeGetItemCount(long nativeCountryAdapterAndroid);
+    private native String nativeGetCountryCodeAt(long nativeCountryAdapterAndroid, int position);
+    private native String nativeGetCountryNameAt(long nativeCountryAdapterAndroid, int position);
+}