finally i was able to solve this problem using this thread:
for anyone having same problem:
the point was i had to hide all navstacks before my google map ,so it can be shown with no problem.
ionViewDidLeave() {
console.log('did leave');
document.getElementById('rootpageorsomething').hidden = true;
}
ionViewWillEnter() {
console.log('will enter');
document.getElementById('rootpageorsomething').hidden = false;
}
thanks.