标题翻译
How to maintain backstack of fragment in Navigation Drawer?
问题
我已经采取了一个活动，并在活动中附加了导航抽屉和主页片段。在那个导航抽屉中有一个“联系我们”的选项。当用户点击该选项时，会打开一个片段。但我无法维护该片段的堆栈。意味着当我在联系我们的片段上时，然后再次使用导航抽屉点击联系我们，它会覆盖之前的片段。我必须按两次返回按钮才能回到主页片段。请帮助我如何维护这个堆栈。以下是我的代码：
navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
int id = item.getItemId();
switch (id) {
case R.id.rate:
Uri uri = Uri.parse("market://details?id=" + getPackageName());
Intent myAppLinkToMarket = new Intent(Intent.ACTION_VIEW, uri);
try {
startActivity(myAppLinkToMarket);
} catch (ActivityNotFoundException e) {
Toast.makeText(getApplicationContext(), "无法找到应用市场！", Toast.LENGTH_SHORT).show();
}
break;
case R.id.contact_us:
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.add(R.id.fragment_container_dashboard, ContactUsFragment.newInstance());
transaction.addToBackStack(null);
transaction.commit();
mDrawerLayout.closeDrawer(GravityCompat.START);
break;
}
return false;
}
});
在这段代码后，我使用以下代码来维护堆栈：
@Override
public void onBackPressed() {
if (getFragmentManager().getBackStackEntryCount() != 0) {
getFragmentManager().popBackStack();
}
else new AlertDialog.Builder(this)
.setMessage("确定要退出吗？")
.setCancelable(false)
.setPositiveButton("是的", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
Dashboard.super.onBackPressed();
}
})
.setNegativeButton("取消", null)
.show();
}
但问题是，每当我按下返回按钮时，它会在“联系我们”片段上显示退出对话框。但我想首先到达主页片段，然后如果我按下返回按钮，它才会显示退出对话框。
英文翻译
I have taken one activity and with activity I have attached navigation drawer and the home fragment. In that navigation drawer there is a option of "Contact Us". When user click on that option a fragment gets open. But I am not able to maintain the stack of that. means when I am on contact us fragment then using navigation drawer again click on contact us it overlaps previous one. I have to press back button 2 times to go on home fragment. Please Help me how to maintain back stack for this. Here is my code..
navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
int id = item.getItemId();
switch (id) {
case R.id.rate:
Uri uri = Uri.parse("market://details?id=" + getPackageName());
Intent myAppLinkToMarket = new Intent(Intent.ACTION_VIEW, uri);
try {
startActivity(myAppLinkToMarket);
} catch (ActivityNotFoundException e) {
Toast.makeText(getApplicationContext(), "Unable to find source market app!", Toast.LENGTH_SHORT).show();
}
break;
case R.id.contact_us:
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.add(R.id.fragment_container_dashboard, ContactUsFragment.newInstance());
transaction.addToBackStack(null);
transaction.commit();
mDrawerLayout.closeDrawer(GravityCompat.START);
break;
}
return false;
}
});
After this code I use this to maintain back stack:
@Override
public void onBackPressed() {
if (getFragmentManager().getBackStackEntryCount() != 0) {
getFragmentManager().popBackStack();
}
else new AlertDialog.Builder(this)
.setMessage("Are you sure you want to exit?")
.setCancelable(false)
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
Dashboard.super.onBackPressed();
}
})
.setNegativeButton("No", null)
.show();
}
But the issue is It's show exit dialogue on contact us fragment when ever I press back button. But I want firstly I reach to home fragment and after that If I press back button then it show exit dialogue.
答案1
得分: 0
我通过在onCreate方法中添加以下内容解决了这个问题。
getSupportFragmentManager().addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
@Override
public void onBackStackChanged() {
if(getSupportFragmentManager().getBackStackEntryCount() == 0){
drawer.setDrawerLockMode(DrawerLayout.LOCK_MODE_UNLOCKED);
menuToggle.setDrawerIndicatorEnabled(true);
// your dialog
}else{
drawer.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED);
menuToggle.setDrawerIndicatorEnabled(false);
// remove to your previous fragment
}
}
});
英文翻译
I solved this by adding this in the onCreate method.
getSupportFragmentManager().addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
@Override
public void onBackStackChanged() {
if(getSupportFragmentManager().getBackStackEntryCount() == 0){
drawer.setDrawerLockMode(DrawerLayout.LOCK_MODE_UNLOCKED);
menuToggle.setDrawerIndicatorEnabled(true);
// your dialog
}else{
drawer.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED);
menuToggle.setDrawerIndicatorEnabled(false);
// remove to your previous fragment
}
}
});
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