clipboard: Enable history collection with a checkbox

The feature is off by default for privacy reasons. The checkbox state is
persisted in the configuration.

The history is immediately cleared when it's disabled. The content of
the system clipboard is visible when the history is enabled.

res/layout/clipboard_pane.xml

@@ -2,7 +2,7 @@
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:background="?attr/colorKeyboard" android:hardwareAccelerated="false">
   <ScrollView android:layout_width="fill_parent" android:layout_height="@dimen/clipboard_view_height">
     <LinearLayout android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="wrap_content">
-      <TextView android:text="@string/clipboard_history_heading" style="@style/clipboardHeading" android:layout_width="fill_parent" android:layout_height="wrap_content"/>
+      <juloo.keyboard2.ClipboardHistoryCheckBox android:text="@string/clipboard_history_heading" style="@style/clipboardHeading" android:layout_width="fill_parent" android:layout_height="wrap_content"/>
       <juloo.keyboard2.ClipboardHistoryView android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="wrap_content" android:divider="?attr/clipboard_divider_color" android:dividerHeight="?attr/clipboard_divider_height"/>
       <TextView android:text="@string/clipboard_pin_heading" style="@style/clipboardHeading" android:layout_width="fill_parent" android:layout_height="wrap_content"/>
       <juloo.keyboard2.ClipboardPinView android:id="@+id/clipboard_pin_view" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="wrap_content" android:divider="?attr/clipboard_divider_color" android:dividerHeight="?attr/clipboard_divider_height"/>

srcs/juloo.keyboard2/ClipboardHistoryCheckBox.java

@@ -0,0 +1,22 @@
+package juloo.keyboard2;
+
+import android.content.Context;
+import android.util.AttributeSet;
+import android.widget.CheckBox;
+import android.widget.CompoundButton;
+
+final class ClipboardHistoryCheckBox extends CheckBox
+  implements CompoundButton.OnCheckedChangeListener
+{
+  public ClipboardHistoryCheckBox(Context ctx, AttributeSet attrs)
+  {
+    super(ctx, attrs);
+    setOnCheckedChangeListener(this);
+  }
+
+  @Override
+  public void onCheckedChanged(CompoundButton _v, boolean isChecked)
+  {
+    ClipboardHistoryService.set_history_enabled(isChecked);
+  }
+}

srcs/juloo.keyboard2/ClipboardHistoryService.java

@@ -27,6 +27,19 @@ public final class ClipboardHistoryService
     return _service;
   }
 
+  public static void set_history_enabled(boolean e)
+  {
+    if (_service == null)
+      return;
+    Config.globalPrefs().edit()
+      .putBoolean("clipboard_history_enabled", e)
+      .commit();
+    if (e)
+      _service.add_current_clip();
+    else
+      _service.clear_history();
+  }
+
   /** The maximum size limits the amount of user data stored in memory but also
       gives a sense to the user that the history is not persisted and can be
       forgotten as soon as the app stops. */
@@ -89,6 +102,8 @@ public final class ClipboardHistoryService
       empty strings. */
   public void add_clip(String clip)
   {
+    if (!Config.globalConfig().clipboard_history_enabled)
+      return;
     int size = _history.size();
     if (clip.equals("") || (size > 0 && _history.get(size - 1).content.equals(clip)))
       return;
@@ -99,6 +114,13 @@ public final class ClipboardHistoryService
       _listener.on_clipboard_history_change();
   }
 
+  public void clear_history()
+  {
+    _history.clear();
+    if (_listener != null)
+      _listener.on_clipboard_history_change();
+  }
+
   public void set_on_clipboard_history_change(OnClipboardHistoryChange l) { _listener = l; }
 
   public static interface OnClipboardHistoryChange
@@ -106,12 +128,8 @@ public final class ClipboardHistoryService
     public void on_clipboard_history_change();
   }
 
-  final class SystemListener implements ClipboardManager.OnPrimaryClipChangedListener
-  {
-    public SystemListener() {}
-
-    @Override
-    public void onPrimaryClipChanged()
+  /** Add what is currently in the system clipboard into the history. */
+  void add_current_clip()
   {
     ClipData clip = _cm.getPrimaryClip();
     if (clip == null)
@@ -120,6 +138,16 @@ public final class ClipboardHistoryService
     for (int i = 0; i < count; i++)
       add_clip(clip.getItemAt(i).getText().toString());
   }
+
+  final class SystemListener implements ClipboardManager.OnPrimaryClipChangedListener
+  {
+    public SystemListener() {}
+
+    @Override
+    public void onPrimaryClipChanged()
+    {
+      add_current_clip();
+    }
   }
 
   static final class HistoryEntry

srcs/juloo.keyboard2/Config.java

@@ -66,6 +66,7 @@ public final class Config
   public boolean pin_entry_enabled;
   public boolean borderConfig;
   public int circle_sensitivity;
+  public boolean clipboard_history_enabled;
 
   // Dynamically set
   public boolean shouldOfferVoiceTyping;
@@ -183,6 +184,7 @@ public final class Config
     current_layout_portrait = _prefs.getInt("current_layout_portrait", 0);
     current_layout_landscape = _prefs.getInt("current_layout_landscape", 0);
     circle_sensitivity = Integer.valueOf(_prefs.getString("circle_sensitivity", "2"));
+    clipboard_history_enabled = _prefs.getBoolean("clipboard_history_enabled", false);
   }
 
   public int get_current_layout()