PLEASE READ CAREFULLY:
Just to be clear about this problem since it is so deeply misunderstood by many people. It is purely a memory issue. It is not encountered nearly as often on phones with 512MB of memory. In my case I have the good ol Droid 1 with 256MB RAM and mine is very prone to having this problem, which for several months now has been completely cured.
Think of your phone like its RAM is very precious space just as electricity was on the Apollo 13 trip to the moon. When you are on the home screen, all is well, you can see your icons and widgets and all are there. When you veer away from home and open memory hungry apps, the memory manager will try to hold other apps (that are not being displayed on the screen, or being ran as background processes) in the RAM memory as long as it can until the current app running in the forefront hogs up all the memory, then the OS must freeze the state of any app that was running previously, so it creates a type of file (to save to the internal flash memory) to remember the state of the program(s) that had been previously ran and saves them so that the OS can rebuild the program to the same state it was in when it had been on the forefront.
The more and more apps you open over the top of the home screen will surely guarantee that you will purge the home app out of the RAM. Some launchers like Launcher Pro have a toggle in them to 'lock into memory', and they can help, but they basically only request to the OS to 'pretty-please leave me running in memory', but there are still many times where the OS will STILL purge the launcher even with this option selected to true.
I have found that on my phone, I have had better results locking the home launcher into memory by using this procedure:
FIX: Reduce REDRAW with launcherpro/ADW *Credit to samsonite801 - Droid Forum - Verizon Droid & the Motorola Droid Forum
By the way, I am Samsonite801 on that forum. I didn't really come up with this procedure, but had previously found it in a developer community, and then after trying out the procedure and verifying that it does indeed do wonders for me, I brought it over to the Droid user forums.
This procedure will help on most people's phones if they also take a pro-active approach to memory management, and also try to do other things that will try to lessen the memory footprint of their launcher to some degree. This means that, if you do attempt to install this
ro.HOME_APP_ADJ=1 toggle into a file called /data/local.prop, then it will lock your home launcher into memory, but if your launcher uses gobs of memory and has a huge footprint then when you open other memory-hungry apps, they may likely crash when they can't use a bunch of memory. Like if I open too many tabs on my xScope 6 browser it will eventually crash when it runs out of memory. This is because the Droid 1 really needs more memory, and this is the real problem. The above line added to the /data/local.prop file is only a bandade really (although if I had a Droid X or something, I'd probably still want to keep the launcher locked into the memory, as then I would even be in a better position to handle it).
But basically, the
ro.HOME_APP_ADJ=1 toggle is just a more reliable way to keep the launcher locked into memory, than the toggle supplied in launchers like Launcher Pro and ADW. This is because this command here requires root access, whereas the 'Lock into Memory' toggle in the launchers DO NOT require root access, therefore, it can only ASK the memory manager what it would like to have but really, it amounts to the memory manager is going to do whatever it wants based on other things it must consider.
There still lies one other redraw issue however. Since the launcher does not cache both a portrait view and a landscape view simultaneously in the RAM, then you will still see a redraw whenever you switch from one to the other. So my advice is to open your app (like messaging app say) in portrait mode FIRST, then rotate phone, open keyboard, and do your typing, then close phone keyboard, rotate back to portrait before hitting the home button. Then it will never redraw. Or rotate the phone WHILE it is on the home screen already (also works), but just don't open an app and rotate and then return to home in the other view. This always results in redraw. I also shut off the auto-rotate feature in LP prefs so that it does not rotate based on the accelerometer, but rather only changes when the keyboard is actually slid open.
Now the actual speed of a redraw is highly dependent on how much stuff your launcher has to redraw (and CPU speed to some extent). I keep my Launcher Pro down to 3 screens, 6 folders, 5 widgets, and 3 scrolling docks, and I have it set in LP Prefs to 'lock in memory' also, and to use 'Light' memory, and compressed caching, and speeds are all set to full fast with no problems.
Just remember, that the reason everyone has a different experience with this problem is because everyone runs different number and type of widgets, different apps in general and it is a completely different balance of memory usage on everyone's phones, whom all run different CPU clock speeds and have different RAM sizes, etc. It is very much a juggling act to find a good balance of the features and widgets you want, against number of home screens, against the hardware you have. If you bog it down too much it will be slower.
I have even had issues with doing updates and installing an updated version of the launcher over an existing version. I always recommend to save your home launcher settings to the backup file (LP and ADW both have means to backup current config), and then completely remove it first before going to the Market to install the updated version. Then you get a true fresh install without any patched code that might have bugs and slow it down. Many times I've seen when the Market's installer had even said it would be completely replacing the old version with a new version, I could, many times, go into the /data/app folder and see there are now 2 apks in there for one given app (named like:
thisapp-1.apk and
thisapp-2.apk. And if you have an app in the /system/app folder (factory shipped apps which don't delete on a phone reset), I've seen as many as 3 related apk files stack up for one app, which just hogs up all your internal flash storage, so before I ever update any app, I always uninstall the old one first. And if it is a system app, I will do the update, but then I move the new apk from /data/app over to /system/app and overwrite the old one that was in system. (always backing up every apk for easy regression if needed).
Hopefully this post offers some insight to this issue of redrawing. Once I have found my perfect balance on my phone, and learned about the work-around to the portrait/landscape switching to avoid redrawing, I never have been plagued by this issue ever since I found my personal recipe. And ultimately, I also realize that this will only work until my hardware becomes completely outdated by software that has more code in it and I will eventually have to upgrade to a phone with more RAM and faster CPU to keep up with the times. But for now, with my Droid 1 which has 256MB RAM and custom kernel running 1000mHz max speed, my current setup works great, and I do not experience redraws , unless if LP ever crashes which is seldom.
report back in a week
