你必须添加Fragment
背堆和片段经理添加听者这样
getSupportFragmentManager().addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
@Override
public void onBackStackChanged() {
if (getSupportFragmentManager().getBackStackEntryCount() > 0) {
getSupportActionBar().setDisplayHomeAsUpEnabled(true); // show back button
toolbar.setNavigationOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
onBackPressed();
}
});
} else {
//show hamburger
getSupportActionBar().setDisplayHomeAsUpEnabled(false);
toggle.syncState();
toolbar.setNavigationOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
drawerLayout.openDrawer(GravityCompat.START);
}
});
}
}
});
非常感谢..它工作.. :) – vini
@vini欢迎编码快乐:) –
Яискалэто оченьдолго!!! Спасибоогромное!!! //我找了很久!!!非常感谢!!! –