Load AbsoluteSizeSpan(int,boolean) constructor via reflection

This will allow us to run on Android 1.5/1.6 devices.

src/com/fsck/k9/K9.java

@@ -2,6 +2,7 @@
 package com.fsck.k9;
 
 import java.io.File;
+import java.lang.reflect.Constructor;
 import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.List;
@@ -22,6 +23,7 @@ import android.os.Environment;
 import android.os.Handler;
 import android.os.Looper;
 import android.text.format.Time;
+import android.text.style.AbsoluteSizeSpan;
 import android.util.Log;
 
 import com.fsck.k9.activity.MessageCompose;
@@ -66,6 +68,10 @@ public class K9 extends Application {
      */
     private static List<ApplicationAware> observers = new ArrayList<ApplicationAware>();
 
+    /**
+     * @see K9#createAbsoluteSizeSpan(int)
+     */
+    private static Constructor<AbsoluteSizeSpan> sAbsoluteSizeSpanConstructor;
 
     public enum BACKGROUND_OPS {
         WHEN_CHECKED, ALWAYS, NEVER, WHEN_CHECKED_AUTO_SYNC
@@ -992,4 +998,47 @@ public class K9 extends Application {
         K9.mAttachmentDefaultPath = attachmentDefaultPath;
     }
 
+    /**
+     * Creates an {@link AbsoluteSizeSpan} object.
+     *
+     * <p>
+     * Android versions prior to 2.0 don't support the constructor with two parameters
+     * ({@link AbsoluteSizeSpan#AbsoluteSizeSpan(int, boolean)}). So we have to perform some
+     * reflection magic to dynamically load the new constructor on devices that support it.
+     * For devices with old Android versions we just use the size as pixels (instead of dip).
+     * </p>
+     *
+     * @param size This is used as the {@code size} parameter for the AbsoluteSizeSpan constructor.
+     * @return a AbsoluteSizeSpan object with the specified text size.
+     */
+    public static AbsoluteSizeSpan createAbsoluteSizeSpan(int size) {
+        if (Integer.parseInt(android.os.Build.VERSION.SDK) < 5) {
+            // For Android 1.5/1.6 simply use the constructor with only the size parameter.
+            // Yes, that will most likely look wrong!
+            return new AbsoluteSizeSpan(size);
+        }
+
+        if (sAbsoluteSizeSpanConstructor == null) {
+            try {
+                sAbsoluteSizeSpanConstructor = AbsoluteSizeSpan.class.getConstructor(int.class, boolean.class);
+            } catch (Exception e) {
+                Log.e(K9.LOG_TAG, "Couldn't get the AbsoluteSizeSpan(int, boolean) constructor", e);
+
+                // Fallback
+                return new AbsoluteSizeSpan(size);
+            }
+        }
+
+        AbsoluteSizeSpan result;
+        try {
+            result = sAbsoluteSizeSpanConstructor.newInstance(size, true);
+        } catch (Exception e) {
+            Log.e(K9.LOG_TAG, "Couldn't call the AbsoluteSizeSpan(int, boolean) constructor", e);
+
+            // Fallback
+            result = new AbsoluteSizeSpan(size);
+        }
+
+        return result;
+    }
 }

src/com/fsck/k9/activity/MessageList.java

@@ -18,7 +18,6 @@ import android.graphics.drawable.Drawable;
 import android.os.Bundle;
 import android.text.Spannable;
 import android.text.SpannableStringBuilder;
-import android.text.style.AbsoluteSizeSpan;
 import android.text.style.ForegroundColorSpan;
 import android.text.style.StyleSpan;
 import android.util.Log;
@@ -2166,7 +2165,7 @@ public class MessageList
                                 0,
                                 noSender.length(),
                                 Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
-                    str.setSpan(new AbsoluteSizeSpan(mFontSizes.getMessageListSender(), true),
+                    str.setSpan(K9.createAbsoluteSizeSpan(mFontSizes.getMessageListSender()),
                                 0,
                                 noSender.length(),
                                 Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
@@ -2255,7 +2254,7 @@ public class MessageList
                             0,
                             message.sender.length() + 1,
                             Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
-                str.setSpan(new AbsoluteSizeSpan(mFontSizes.getMessageListSender(), true),
+                str.setSpan(K9.createAbsoluteSizeSpan(mFontSizes.getMessageListSender()),
                             0,
                             message.sender.length() + 1,
                             Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);