Respect system font size in message list.

- This makes dimensions according to scaled font sizes, and also resets
the activity properly (invalidating drawing caches) when that font size
happens.

Bug: 5287961
Change-Id: I04cf117b027befd6a065edeadf95187f62fffc8a

res/values/dimensions.xml

@@ -18,8 +18,8 @@
 
 <resources>
     <dimen name="button_minWidth">100sp</dimen>
-    <dimen name="message_list_item_height_wide">70dip</dimen>
-    <dimen name="message_list_item_height_normal">70dip</dimen>
+    <dimen name="message_list_item_height_wide">70sp</dimen>
+    <dimen name="message_list_item_height_normal">70sp</dimen>
     <dimen name="message_list_item_color_tip_width">35dip</dimen>
     <dimen name="message_list_item_color_tip_height">6dip</dimen>
     <dimen name="message_list_badge_margin">4dip</dimen>

src/com/android/email/activity/EmailActivity.java

@@ -19,6 +19,7 @@ package com.android.email.activity;
 import android.app.Activity;
 import android.app.Fragment;
 import android.content.Intent;
+import android.content.res.Configuration;
 import android.os.Bundle;
 import android.os.Handler;
 import android.text.TextUtils;
@@ -63,6 +64,8 @@ public class EmailActivity extends Activity implements View.OnClickListener, Fra
     /** Loader IDs starting with this is safe to use from ActionBarController. */
     static final int ACTION_BAR_CONTROLLER_LOADER_ID_BASE = 200;
 
+    private static float sLastFontScale = -1;
+
     private Controller mController;
     private Controller.Result mControllerResult;
 
@@ -161,6 +164,15 @@ public class EmailActivity extends Activity implements View.OnClickListener, Fra
     protected void onCreate(Bundle savedInstanceState) {
         if (Logging.DEBUG_LIFECYCLE && Email.DEBUG) Log.d(Logging.LOG_TAG, this + " onCreate");
 
+        float fontScale = getResources().getConfiguration().fontScale;
+        if (sLastFontScale != -1 && sLastFontScale != fontScale) {
+            // If the font scale has been initialized, and has been detected to be different than
+            // the last time the Activity ran, it means the user changed the font while no
+            // Email Activity was running - we still need to purge static information though.
+            onFontScaleChangeDetected();
+        }
+        sLastFontScale = fontScale;
+
         // UIController is used in onPrepareOptionsMenu(), which can be called from within
         // super.onCreate(), so we need to initialize it here.
         initUIController();
@@ -399,4 +411,11 @@ public class EmailActivity extends Activity implements View.OnClickListener, Fra
              }
         }
     }
+
+    /**
+     * Handle a change to the system font size. This invalidates some static caches we have.
+     */
+    private void onFontScaleChangeDetected() {
+        MessageListItem.resetDrawingCaches();
+    }
 }

src/com/android/email/activity/MessageListItem.java

@@ -183,6 +183,16 @@ public class MessageListItem extends View {
         }
     }
 
+    /**
+     * Invalidate all drawing caches associated with drawing message list items.
+     * This is an expensive operation, and should be done rarely, such as when system font size
+     * changes occurs.
+     */
+    public static void resetDrawingCaches() {
+        MessageListItemCoordinates.resetCaches();
+        sInit = false;
+    }
+
     /**
      * Sets message subject and snippet safely, ensuring the cache is invalidated.
      */

src/com/android/email/activity/MessageListItemCoordinates.java

@@ -224,6 +224,13 @@ public class MessageListItemCoordinates {
         return SUBJECT_LENGTHS[mode];
     }
 
+    /**
+     * Reset the caches associated with the coordinate layouts.
+     */
+    static void resetCaches() {
+        mCache.clear();
+    }
+
     /**
      * Returns coordinates for elements inside a conversation header view given
      * the view width.