Add a new "Voice input & output" top-level section of system settings.

This replaces the existing "Text-to-speech" section, placing that
inside, along with a link to the newly exposed voice search settings
(which will soon be expanded) and a link to the LatinIME settings
(pending a link to a new section in LatinIME for just voice settings,
including the comma setting and a new input language setting).

The VoiceSearch and LatinIME links are smart enough to remove themselves
if those don't exist on the device.

src/com/android/settings/VoiceInputOutputSettings.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2010 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;
+
+import android.content.Context;
+import android.content.Intent;
+import android.content.pm.PackageManager;
+import android.os.Bundle;
+import android.preference.Preference;
+import android.preference.PreferenceActivity;
+import android.preference.PreferenceGroup;
+
+import java.util.List;
+
+/**
+ * Settings screen for voice input/output.
+ */
+public class VoiceInputOutputSettings extends PreferenceActivity {
+    
+    private static final String KEY_PARENT = "parent";
+    private static final String KEY_VOICE_SEARCH_SETTINGS = "voice_search_settings";
+    private static final String KEY_KEYBOARD_SETTINGS = "keyboard_settings";
+    
+    @Override
+    protected void onCreate(Bundle icicle) {
+        super.onCreate(icicle);
+
+        addPreferencesFromResource(R.xml.voice_input_output_settings);
+        
+        removePreferenceIfNecessary(KEY_VOICE_SEARCH_SETTINGS);
+        removePreferenceIfNecessary(KEY_KEYBOARD_SETTINGS);
+    }
+
+    /**
+     * Removes a preference if there is no activity to handle its intent.
+     */
+    private void removePreferenceIfNecessary(String preferenceKey) {
+        PreferenceGroup parent = (PreferenceGroup) findPreference(KEY_PARENT);
+        
+        Preference preference = parent.findPreference(preferenceKey);
+        if (preference == null) {
+            return;
+        }
+
+        Intent intent = preference.getIntent();
+        if (intent != null) {
+            PackageManager pm = getPackageManager();
+            if (!pm.queryIntentActivities(intent, 0).isEmpty()) {
+                return;
+            }
+        }
+        
+        // Did not find a matching activity, so remove the preference.
+        parent.removePreference(preference);
+    }
+}