Add VPN settings classes to Settings app.

PATCH SET 2:
+ Add import com.android.settings.R

PATCH SET 3:
+ Remove @Override interface methods to be compilable by Java 1.5.

PATCH SET 4:
+ Add import android.net.vpn.VpnManager

PATCH SET 5:
+ Add license headers.

PATCH SET 6:
+ Remove Constant.java and move the constants to VpnSettings.
+ Make AuthenticationActor implement DialogInterface's handlers.
+ Remove trailing spaces.

PATCH SET 7:
+ Remove default username.

src/com/android/settings/vpn/SingleServerEditor.java

@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) 2007 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settings.vpn;
+
+import com.android.settings.R;
+
+import android.content.Context;
+import android.net.vpn.SingleServerProfile;
+import android.net.vpn.VpnProfile;
+import android.preference.EditTextPreference;
+import android.preference.Preference;
+import android.preference.PreferenceGroup;
+
+/**
+ * The class for editing {@link SingleServerProfile}.
+ */
+class SingleServerEditor implements VpnProfileEditor {
+    private EditTextPreference mServerName;
+    private EditTextPreference mDomainSuffices;
+    private SingleServerProfile mProfile;
+
+    public SingleServerEditor(SingleServerProfile p) {
+        mProfile = p;
+    }
+
+    //@Override
+    public VpnProfile getProfile() {
+        return mProfile;
+    }
+
+    //@Override
+    public void loadPreferencesTo(PreferenceGroup subpanel) {
+        Context c = subpanel.getContext();
+        subpanel.addPreference(createServerNamePreference(c));
+    }
+
+    //@Override
+    public String validate(Context c) {
+        return (mProfile.isCustomized()
+                ? null
+                : (Util.isNullOrEmpty(mServerName.getText())
+                        ? c.getString(R.string.vpn_error_server_name_empty)
+                        : null));
+    }
+
+    /**
+     * Creates a preference for users to input domain suffices.
+     */
+    protected EditTextPreference createDomainSufficesPreference(Context c) {
+        EditTextPreference pref = mDomainSuffices = new EditTextPreference(c);
+        pref.setTitle(R.string.vpn_dns_search_list_title);
+        pref.setDialogTitle(R.string.vpn_dns_search_list_title);
+        pref.setPersistent(true);
+        pref.setText(mProfile.getDomainSuffices());
+        pref.setSummary(mProfile.getDomainSuffices());
+        pref.setOnPreferenceChangeListener(
+                new Preference.OnPreferenceChangeListener() {
+                    public boolean onPreferenceChange(
+                            Preference pref, Object newValue) {
+                        String v = ((String) newValue).trim();
+                        mProfile.setDomainSuffices(v);
+                        pref.setSummary(checkNull(v, pref.getContext()));
+                        return true;
+                    }
+                });
+        return pref;
+    }
+
+    private Preference createServerNamePreference(Context c) {
+        EditTextPreference serverName = mServerName = new EditTextPreference(c);
+        String title = c.getString(R.string.vpn_server_name_title);
+        serverName.setTitle(title);
+        serverName.setDialogTitle(title);
+        serverName.setSummary(checkNull(mProfile.getServerName(), c));
+        serverName.setText(mProfile.getServerName());
+        serverName.setPersistent(true);
+        serverName.setOnPreferenceChangeListener(
+                new Preference.OnPreferenceChangeListener() {
+                    public boolean onPreferenceChange(
+                            Preference pref, Object newValue) {
+                        String v = ((String) newValue).trim();
+                        mProfile.setServerName(v);
+                        pref.setSummary(checkNull(v, pref.getContext()));
+                        return true;
+                    }
+                });
+        return mServerName;
+    }
+
+
+   String checkNull(String value, Context c) {
+        return ((value != null && value.length() > 0)
+                ? value
+                : c.getString(R.string.vpn_not_set));
+   }
+}