Hello I just want to switch from a fragment to another using a button. Nothing difficult... the code works well but I have spent a lot of time because Android goesto error if I hook frameLayout with autocompile.
I'm explaining better:
package com.example.fragcookbook;
import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.FrameLayout;
public class MainActivity extends AppCompatActivity {
FragmentOne mFragmentOne;
FragmentTwo mFragmentTwo;
int showingFragment=0;
#Override
protected void onCreate ( Bundle savedInstanceState ) {
super.onCreate (savedInstanceState);
setContentView (R.layout.activity_main);
mFragmentOne = new FragmentOne();
mFragmentTwo = new FragmentTwo();
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.add(R.id.frameLayout, mFragmentOne);
fragmentTransaction.commit();
showingFragment=1;
}
public void switchFragment(View view) {
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
if (showingFragment==1) {
fragmentTransaction.replace(R.id.frameLayout, mFragmentTwo);
showingFragment = 2;
} else {
fragmentTransaction.replace(R.id.frameLayout, mFragmentOne);
showingFragment=1;
}
fragmentTransaction.commit();
}
In all rows where you see R.id.frameLayout i have to handly write frameLayout..... Android colors it red but It works...
But if i choose the resource with autocompile...
...when i run app Android gives me this error....
Why? is not best practice use autocompile?
Thanks in advance
Try this may will help you.Go to "File" -> "Invalidate Caches...", and select "Invalidate and Restart" option to fix this.
Or
Restar you android studio and emulator
I am getting a cannot resolve symbol error on CrimeFragment and I don't know why. I am a beginner so I'm not sure how to fix this. Here is the code for CrimeActivity.java
package com.bignerdranch.android.criminalintent;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
public class CrimeActivity extends FragmentActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_crime);
FragmentManager fm = getSupportFragmentManager();
Fragment fragment = fm.findFragmentById(R.id.fragment_container);
if (fragment == null) {
fragment = new CrimeFragment();
fm.beginTransaction()
.add(R.id.fragment_container, fragment)
.commit();
}
}
}
Seems like you aren't importing your class CrimeFragment
Make sure that CrimeFragment.java and Crime.java are in the right packages. Select "Packages" view in the top-left corner. If these files hang around separately at the bottom, drag and drop them into the "com.(..).criminalintent" package.
I tried to add a fragment on button click action inside an adapter which extends a BaseAdapter.
But to use fragments the class has to extend Fragment to use the FragmentManager.
I've imported :
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
But still facing an error here:
FragmentManager fragmentManager=getFragmentManager();
I've also tried to give the activity reference when getting the FragmentManager,it gave more errors.
Any help would be much appreciated.
Thanks in advance.
Here is my adapter code:
Drawer item(view) onclick action:
view.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
if (position == 1)// Home
{
Home2Fragment fragment = new Home2Fragment();
FragmentManager fragmentManager=getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager
.beginTransaction();
fragmentTransaction.add(fragment, null);
fragmentTransaction.commit();
}
}
});
Because importing Fragments from support library so, use getSupportFragmentManager method to get FragmentManager :
FragmentManager fragmentManager=<Activity_Context>.getSupportFragmentManager();
Need to use FragmentActivity context to access FragmentManager and also make sure extending FragmentActivity instead of Activity.
It is considered good practice to use let Adapters be an inner class of the List that uses them. That gives the adapter full access to the class using them and if it's a fragment, you can use the fragment manager.
I created a class called SlidingFragment that extends from Fragment, and in my MainActivity I put these lines:
MainActivity.java :
public class MainActivity extends FragmentActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setUpView();
setUpFragment();
}
void setUpView(){
setContentView(R.layout.activity_main);
}
void setUpFragment(){
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
SlidingFragment fragment = new SlidingFragment();
transaction.replace(R.id.sample_content_fragment, fragment);
transaction.commit();
}
}
The problem is that the replace() method of the FragmentTransaction class can't recognize the second argument fragment which is a SlidingFragment object. I get this:
wrong second argument type found.'SlidingFragment' required 'android.support.v4.app.Fragment'.
replace(int,android.support.v4.app.Fragment)
to
replace(int,com.example.g514110.IhmSlidingTabs.SlidingFragment)
I understand the problem, but I don't know how to solve it.
Can someone please help.Thanks
Do that SlidingFragment extends
import android.support.v4.app.Fragment;
and not
android.app.Fragment
Make sure your SlidingFragment is extending android.support.v4.app.Fragment. Based on this compiler error, it currently is not.
Before I am also facing this issue , I did few changes . Now it's Workking Fine
New frgment page Eg : home_fragment
import android.support.v4.app.Fragment;
Main XML Design must contain any layout with your id eg :
android:id="#+id/fragment_container"
Main Java Class
import android.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
Click Event
home_fragment fragment = new home_fragment();
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.fragment_container, fragment);
transaction.commit();
This Code Workking Fine For Me
The scenario I am faced with, is in my application I have a single pane and dual pane style layout. Rather than individually handle every single navigation operation possible between the screens, for every different style of layout, I am using a function which sets up the layout correctly when given the desired screen.
It is basically a switch statement for each screen in the app, with a nested switch statement in each screen to handle each layout style. This is what I'm talking about in code:
protected void setupScreen() {
switch(currentScreen) {
case SCREEN_ONE:
switch(currentLayout) {
case SINGLE_PANE:
// Perform actions to setup the screen
break;
case DUAL_PANE:
// Perform actions to setup the screen
break;
}
break;
case SCREEN_TWO:
switch(currentLayout) {
case SINGLE_PANE:
// Perform actions to setup the screen
break;
case DUAL_PANE:
// Perform actions to setup the screen
break;
}
break
// ... etc ....
}
}
In the section where I want to perform the actions to setup the screen, this consists of the following basic three operations:
// Create the fragments if necessary
if (screenFragment == null) {
screenFragment = new myFragment();
}
// Remove the existing fragments from the layout views
// HOW???
// Add the fragments for this screen to the view
getSupportFragmentManager().beginTransaction().add(pane1.getId(), myFragment, "myFragment").commit();
As you can see, what I am struggling with is how to do the second step. How do you remove all Fragments from a given View without knowing exactly which ones you are wanting to remove? The closest I have found is FragmentTransaction.replace() which does successfully do this for every case but when it turns out you are replacing a Fragment with the same fragment. In this case, it does not remove all, then add (like the documentation suggests), it just seems to remove. Is this an issue with using the compatibility libraries or is it not the way FragmentTransaction.replace() should be used?
In any case, how should I go about doing this? Do I have to code a removeAllFragments() function to go through every fragment and detach it or is there a way to do the first half of what the 'two in one' FragmentTransaction.replace() function claims to do?
None of the other answers were really working for me. Here's what I did:
List<Fragment> al = getSupportFragmentManager().getFragments();
if (al == null) {
// code that handles no existing fragments
return;
}
for (Fragment frag : al)
{
// To save any of the fragments, add this check.
// A tag can be added as a third parameter to the fragment when you commit it
if (frag == null || frag.getTag().equals("<tag-name>")) {
continue;
}
getSupportFragmentManager().beginTransaction().remove(frag).commit();
}
or, if you're forced to use it (but not recommended):
.commitAllowingStateLoss();
Also, if you're removing all fragments from the view multiple times, you might consider checking if the current frag is null or isDetached() or isRemoving() or you might get NullPointerExceptions.
Update: The documentation for getSupportFragmentManger().getFragments() is apparently hidden now, but still works just fine in my code. Here's the screenshot of the documentation:
Having said that, since it is hidden, they no longer want this method used, so see my update below.
Update 8-4-15: If you're not using the support library for fragments, there is unfortunately no getFragments() available, but there are still a couple, more inconvenient, options.
Give each fragment a tag or id upon creation, and iterate through them to process each fragment as desired.
Create a listener using onAttachListener so each time a new fragment is attached to the activity, you can store that fragment, and then iterate through that data structure to process each fragment as desired.
When not using the getSupportFragmentManager(), to process a transaction you will need to use getFragmentManager() instead.
The typical mechanism is to use FragmentManager.findFragmentByTag() . You use this and add tags to your fragments (or the alternative for id's). This way you can determine what fragments are currently being managed. Then, once you have a handle to a present fragment (findFragmentByTag returns non-null), you can use FragmentManager.beginTransaction() to start a FragmentTransaction and remove / add the necessary fragments. Working in this way will allow you to avoid the 're-adding' process for the fragment you want to keep.
What I'd probably do is have code like so: (warning psuedo code)
Fragment pane1 = FragmentManager.findFragmentByTag("myFragmentPane1");
Fragment pane2 = FragmentManager.findFragmentByTag("myFragmentPane2");
setupScreen(pane1, pane2);
You should also consider sub-classes of your class instead of having 'everything in one class'. You have a fairly obvious case of Martin Fowler's Replace Conditional with Subclass. Otherwise, I fear this is going to be incredibly hard to manager when you add another screen.
If you use android.support.v4.app.Fragment you can do this:
List<Fragment> fragments = getSupportFragmentManager().getFragments();
if (fragments != null) {
for (Fragment fragment : fragments) {
getSupportFragmentManager().beginTransaction().remove(fragment).commit();
}
}
Turns out FragmentTransaction.replace() is the correct operation and should work correctly. It only does not work when using ActionBarSherlock and SherlockFragmentActivity so I can only assume it is a bug in this compatibility library.
I have confirmed this through using the code below to implement the desired behaviour through Android on API11+, the android compatibility library, and ActionBarSherlock. It only breaks in the last instance.
package com.test.test;
import com.actionbarsherlock.app.SherlockFragmentActivity;
import android.os.Bundle;
import android.content.Context;
import android.graphics.Color;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.FrameLayout;
import android.widget.LinearLayout;
import android.widget.LinearLayout.LayoutParams;
import android.widget.TextView;
public class MainActivity extends SherlockFragmentActivity {
// Consistent fragment instance
myFragment myFrag = null;
// Views
FrameLayout fl = null;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
LinearLayout ll = new LinearLayout(this);
ll.setOrientation(LinearLayout.VERTICAL);
Button b = new Button(this);
b.setText("Repeat");
b.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// Reattach the same fragment
getSupportFragmentManager().beginTransaction().replace(fl.getId(), myFrag).commit();
}
});
fl = new FrameLayout(this);
fl.setId(200);
fl.setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
myFrag = new myFragment();
getSupportFragmentManager().beginTransaction().add(fl.getId(), myFrag).commit();
ll.addView(b);
ll.addView(fl);
setContentView(ll);
}
public static class myFragment extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
TextView tv = new TextView(getActivity());
tv.setText("My fragment");
tv.setGravity(Gravity.CENTER);
tv.setBackgroundColor(Color.RED);
return tv;
}
}
}
This is more or less how I have handled this. Have all your fragments implement an interface something like:
public interface NamedFragment{
public FragmentName getFragmentName();
}
Make an enum corresponding to your fragments:
public enum FragmentName{
SOME_FRAGMENT,
SOME_OTHER_FRAGMENT;
}
Then in your fragment switching activity:
// Get the manager and transaction separately so you can use both:
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction ft = fragmentManager.beginTransaction();
// Get a reference to the fragment(s) currently in the container(s)
Fragment currentFragment = fragmentManager.findFragmentById(position);
FragmentName cFragmentName =
((NamedFragment) currentFragment).getFragmentName();
Fragment nextFragment =
Fragment.instantiate(this, some_new_fragment_string);
FragmentName nFragmentName =
((NamedFragment) nextFragment).getFragmentName();
// Compare the "names"
if(cFragmentName != nFragmentName){
ft.replace(position, nextFragment);
}
You'll have to change things around a little to fit your particulars.