2009/11/23
How to create a wordpress widget control panelFor my curiosity, I tried to create a simple Wordpress widget the other
day to find out how it works. There is a ton of posts online to tutor
you from scratch. Some of them are very clear and helpful. I recommend
the following:
As
for me, I tried to realize a widget with database activities, i.e. to
create and drop tables, insert and update records. There is another one
from Wordpress Codex which is ultimately helpful.
This
post is in no place to substitute any of them listed above. However,
when I was trying with my idea, everything works together well except
that the code in the control panel method of my widget always gets
executed twice! In terms of database, that is redundant data.
If you did follow those posts, your widget's control panel method will look like this:
03 | //essential declaration |
05 | //set table name again |
06 | $table_name = $wpdb->prefix . "mytable"; |
07 | //test if the form is submit,that is the save button clicked, get the arguments from the form |
08 | if ( isset($_POST['mywidget-submit'])){ |
09 | //some parameter transaction here |
12 | $insertsql='INSERT INTO ' |
17 | //execute query and write into database |
18 | $wpdb->query( $insertsql ); |
23 | //design the control panel form here and output |
24 | $control_form='<input name="mywidget-submit" value="1" type="hidden">' |
It
is absolutely right and working. If you are just using
add,update,delete_option (refer to the Wordpress functions) to
manipulate your parameters. This is totally fine. In my case, the
INSERT statement will be run twice every time the "Save" button is hit
on the widget control panel.
Here is how it works:
When the
"Save" button is pressed,the "hidden" input control in our control
panel form is submitted and the whole is method is called. Now that we
test the value from $_POST if the "hidden" control is submit and run
the code to insert the Sql statement.
I suspect that when it is
done, the control panel will be reloaded again by Wordpress however the
$_POST['mywidget-submit'] status is never changed. That's why it
happens twice every time.
My solution to this is simple (I
believe this is not a perfect one. Let me know if you have others.) To
explicitly unset the &_POST['mywidget-submit'] when the code is
run, in this case, just after the Sql statement is issued.
1 | //unset the post array otherwise the query is run twice |
2 | unset($_POST['mywidget-submit']); |
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