like this...?

what I've tried to implement (can't test) is a situation where a variable called "falseTracker" keeps track of the number of times the if statement with dist() is false.  Then, when the for loop is over, I ask if the falseTracker equals thelength of the object array.  The idea being that the length of the object is the max number of times the previous if statement could have been false.  If the false tracker equals the length of the object array, then do some stuff.

If you want you could probably move the if/then falseTracker test inside the for loop but since you only want to know after the loop is done, testing each time in the loop seemed unnecessary to me.

1. int falseTracker = 0;
2. 
   
3. void mousePressed() {
4. 
   
5.   for (int i = 1; i < objectArray.length; i++) {
6.     
7.       if (dist(mouseX, 
8.                 mouseY, 
9.                 objectArray[i].xpos[objectArray[i].xpos.length - 1], 
10.                 objectArray[i].ypos[objectArray[i].xpos.length - 1]) < thresh) {
11. 
    
12.                       objectArray[i].updatePosition(mouseX, mouseY);  //IF TRUE
13. 
    
14.       } else {
15.                       falseTracker++; //IF FALSE
16.    
17.       } //end if statement 
18.  
19.    }// end for loop
20.    
21.    if(falseTracker == objectArray.length) {
22.       
23.             //DO THAT THING YOU WANT TO DO
24.             falseTracker = 0; //reset false tracker
25.    
26.     } //end if
27. 
    
28. } //end mousePressed