Unknown Intent Flag on Launcher Activity

2020-02-14 05:28发布

问题:

I have an Activity with launchmode = "singleInstance" and it is the launcher Activity of the app. Now I am trying to detect which Flag my Activity was/will be launched with, but I can not find the flag id with the Intent Flags on the documented page; this is the flag

String version of the Flag id is 270532608

and String version of the Intent is

04-25 20:18:57.061: V/logtag(1665): Intent { act=android.intent.action.MAIN 
        cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=<filtered> }

when the application first starts, the system calls my Activity with this Flag = Intent.FLAG_ACTIVITY_NEW_TASK or string version = 268435456 (which it should) but when I quit the app, and start it once more from the launcher I get this flag 0x10200000 instead of the previous flag

so my question is can anyone tell me what Flag this is?

and why my activity is being called with it?

and are there any other instances from the launcher that my activity might be triggered with a different flag aside from the unknown one & 0x10200000?

回答1:

It's a combination of the flags:

public static final int FLAG_ACTIVITY_NEW_TASK = 0x10000000;

and

public static final int FLAG_ACTIVITY_RESET_TASK_IF_NEEDED = 0x00200000;

0x10000000 is the hexadecimal notation for 268435456.
0x00200000 is the hexadecimal notation for 2097152.
If you add these numbers, you get:
0x10200000, which is the hexadecimal notation for 270532608.

So the first time you start your app, you just get FLAG_ACTIVITY_NEW_TASK, but the second time you will also get FLAG_ACTIVITY_RESET_TASK_IF_NEEDED. This is just a bitwise OR operation. To check if your desired flag is active, you can do a bitwise AND like this:

boolean hasNewTaskFlag = (flg & FLAG_ACTIVITY_NEW_TASK) != 0;


回答2:

First of all, this flag 0x10200000 value is in Hexadecimal not in Decimal that's why you might not find any useful info if you tried to Google it.

That's why you have to convert it first to Decimal. Then you will see that the real flag value is 270532608 which means start a new task over the previous one

why my activity is being called with it?

Because you probably resuming the instance that was in the background (Recent app list). Not starting a new instance

If you want to read more about this intent flag click here

reference: Start new activity in window manager