强制显示actionbar Overflow 选项

private void forceShowOverflowIcon(boolean isShow) {
try {
 ViewConfiguration config = ViewConfiguration.get(this);
 java.lang.reflect.Field menuKeyField = ViewConfiguration.class.getDeclaredField("sHasPermanentMenuKey");


 if (menuKeyField != null) {
   menuKeyField.setAccessible(isShow);
   menuKeyField.setBoolean(config, false);
 }
}
catch (Exception e) {
 // presumably, not relevant
}
}