clear

问题 I have uploaded an apk (version 1.0) with 22 tables in SQLite Database on Google Playstore. Now i want to update database with 36 tables in new version (version 2.0) of application. I am storing datebase at default location so when i press "Clear data" in Application Manager , database is gonna deleted. I just want to know how to delete old database (same as clear data) when user update new version? Update: If is there any solution for clear data while updating application from play store

问题 I have a program that is creating an ItemizedOverlay and a map. Everything works fine upon startup. When you close ande re-open the app, I am using onRestart() to get updated information from my server and update the map. The problem is that at this point, the ItemizedOverlay still contains the old items, and then proceeds to add the new data to the existing data. I am looking for a way to clear out the ItemizedOverlay. There does not appear to be an ItemizedOveraly.clear, or any similar

问题 Is it possible to clear the data of a live gamecenter leaderboard (not sandbox one)? If its not possible to clear, is there a way to hide a leaderboard from showing? Thank you. 回答1: There is no way to reset a Game Center leaderboard category or to remove a category once it's been launched in a live app. Once a leaderboard has gone live for any version of your app, it cannot be removed. From posts: Delete Leaderboard Reset Leaderboard 回答2: Go to that leaderboard in iTunesConnect and change the

问题 This is a general question and something that dawned on me and seemed to make sense. I have seen many people use clearing divs <div class="clear" /> and know this is sometimes frowned upon as it is extra markup. I recently started using <hr class="clear" /> as it seams representative of its actual purpose. Both referencing of course: .clear{clear:both;} I am looking to get some opinions if an hr tag makes more sense than a div to clear content 回答1: According to the HTML5 spec, the hr element

问题 My code currently looks something like this (these steps splitted into multiple functions): /* open file */ FILE *file = fopen(filename, "r+"); if(!file) { /* read the file */ /* modify the data */ /* truncate file (how does this work?)*/ /* write new data into file */ /* close file */ fclose(file); } I know I could open the file with in "w" mode, but I don't want to do this in this case. I know there is a function ftruncate in unistd.h / sys/types.h , but I don't want to use these functions

问题 I'm using Eclipse for writing Python, and I want to be able to easily clear the screen. I've seen this question, and tried (among other things suggested there) the following solution import os def clear(): os.system('cls' if os.name == 'nt' else 'clear') but it doesn't entirely solve my problem. Instead of clearing the screen, the routine prints a small square (as if wanting to print an unknown character) to the command output window in Eclipse. Typing cls in the command line works perfectly

问题 Many times there is a clear method, that removes all the items from the collections, are these items disposed also. Like, toolStripMenuItem.DropDownItems.Clear(); is sufficient, or should I have to call like that: foreach (ToolStripItem item in toolStripMenuItem.DropDownItems) { toolStripMenuItem.DropDownItems.Remove(item); item.Dispose(); } Edit: Well ToolStripItem is an example not a question, for those who says Clear is enough I found another example, TabControl has also item collection

问题 I would like to remove all the elements in the String array for instance: String example[]={"Apple","Orange","Mango","Grape","Cherry"}; Is there any simple to do it,any snippet on it will be helpful.Thanks 回答1: If example is not final then a simple reassignment would work: example = new String[example.length]; This assumes you need the array to remain the same size. If that's not necessary then create an empty array: example = new String[0]; If it is final then you could null out all the

问题 All the time my code is riddled with <div> 's that are used to clear/expand a div to look correct. Whenever it doesn't look correct, I add a <div style="clear:both;"> and it fixes the problem in IE7. How do I avoid doing this? I mess with the overflow:auto , overflow:hidden and I get nothing. Thanks in advance 回答1: One common method is the clearfix class. Instead of needing extraneous <div style="clear:both;"> elements (as you have been doing) after the floating element, you simply add this

问题 I fear this is a really stupid question, but here goes: Why does the clear method in Java's default LinkedList implementation bother to walk the list and unhook all the nodes? Why not just unhook the header and leave the rest of the list connected -- the GC will get it anyway, no? Here's the method: /** * Removes all of the elements from this list. */ public void clear() { Entry<E> e = header.next; while (e != header) { Entry<E> next = e.next; e.next = e.previous = null; e.element = null; e =