Android: Wizard like Activity with Fragments

androidandroid-activityfragmentwizard

Helo.

I read a lot here and on other sites, but it seems that no one have a working solution for using fragments as wizard like app.

I try to implement one, but got some problems at the moment.

Here is the Activity XML with placeholder for Step-Fragments:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:ads="http://schemas.android.com/apk/lib/com.google.ads"
  android:layout_width="match_parent"
  android:layout_height="match_parent" >

  <FrameLayout
    android:id="@+id/fragment_container"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_above="@+id/cmd_previous"
    android:layout_alignParentTop="true" >
  </FrameLayout>

  <Button
    android:id="@+id/cmd_previous"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_alignParentLeft="true"
    android:layout_alignRight="@+id/center_separator_buttons"
    android:text="@string/rpz_cmd_perv" />

  <View
    android:id="@+id/center_separator_buttons"
    style="@style/wd_center_aligner"
    android:layout_alignParentBottom="true" />

  <Button
    android:id="@+id/cmd_next"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/center_separator_buttons"
    android:layout_alignParentBottom="true"
    android:layout_alignParentRight="true"
    android:text="@string/rpz_cmd_next" />

</RelativeLayout>

In OnCreate I add the first step to the activity:

@Override
protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_report_wizard);

  if (this.getIntent().getExtras() != null) {
    Bundle extra = this.getIntent().getExtras();
    if (extra.containsKey(ISelected.ID_KEY)) {
      _ID = extra.getLong(ISelected.ID_KEY);
    }
  }

  if (findViewById(R.id.fragment_container) != null && savedInstanceState == null) {
    _ReportTypeAndName = new ReportWizardTypeAndNameFragment();
    _ReportTypeAndName.setArguments(getIntent().getExtras());
    getSupportFragmentManager().beginTransaction().add(R.id.fragment_container, _ReportTypeAndName).commit();
  }
}

The NEXT-button replace the current Fragment with new one. This seems to work fine.

private void runNext(View view) {
  switch (_CurrentPage) {
    case ReportTypeAndName:
      _ReportSelect = new ReportWizardSelectFragment();
      _ReportSelect.setArguments(getIntent().getExtras());
      getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, _ReportSelect).addToBackStack(null).commit();

      _CurrentPage = ReportWizardPage.ReportSelect;
      break;

    case ReportSelect:
      _CurrentPage = ReportWizardPage.ReportPreview;
      break;

    case ReportPreview:
      _CurrentPage = ReportWizardPage.None;
      break;

    default:
      break;
  }
}

But on the PREVIOUS-Button, this doesn't work.

private void runPrevious(View view) {
  switch (_CurrentPage) {
    case ReportTypeAndName:
      // Umstellung des Typs
      _CurrentPage = ReportWizardPage.None;
      this.finish();
      break;

    case ReportSelect:
      _ReportTypeAndName = new ReportWizardTypeAndNameFragment();
      _ReportTypeAndName.setArguments(getIntent().getExtras());
      getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, _ReportTypeAndName).commit();

      _CurrentPage = ReportWizardPage.ReportTypeAndName;
      break;

    case ReportPreview:
      _CurrentPage = ReportWizardPage.ReportSelect;
      break;

    default:
      break;
  }
}

I got the following Error (LogCat):

FATAL EXCEPTION: main
android.view.InflateException: Binary XML file line #13: Error inflating class fragment
  at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:697)
  at android.view.LayoutInflater.rInflate(LayoutInflater.java:739)
  at android.view.LayoutInflater.inflate(LayoutInflater.java:489)
  at android.view.LayoutInflater.inflate(LayoutInflater.java:396)
  at de.webducer.android.worktime.beta.ui.fragment.ReportWizardTypeAndNameFragment.onCreateView(ReportWizardTypeAndNameFragment.java:40)
  at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:870)
  at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1080)
  at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:622)
  at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1416)
  at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:420)
  at android.os.Handler.handleCallback(Handler.java:605)
  at android.os.Handler.dispatchMessage(Handler.java:92)
  at android.os.Looper.loop(Looper.java:137)
  at android.app.ActivityThread.main(ActivityThread.java:4424)
  at java.lang.reflect.Method.invokeNative(Native Method)
  at java.lang.reflect.Method.invoke(Method.java:511)
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
  at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.IllegalArgumentException: Binary XML file line #13: Duplicate id 0x7f05008b, tag null, or parent id 0x0 with another fragment for de.webducer.android.worktime.beta.ui.fragment.ReportTypeSelectorSpinnerFragment
  at android.support.v4.app.FragmentActivity.onCreateView(FragmentActivity.java:275)
  at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:669)
  ... 18 more

The line 40 of the Fragment is the inflater of them

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
  return inflater.inflate(R.layout.frag_report_wizard_1, container, false);
}

How can I bind (add/remove) the fragments without getting duplicate IDs? Or how can I reuse the fragment without new View-Initialization?

enter image description here

Best Answer

Put your fragments in the backstack and call them back as needed.

Add it to the backstack using addToBackStack:

list = new ListFragment_List();
getFragmentManager().beginTransaction().replace(R.id.pane, listlist).addToBackStack(null).commit();

Pull it back up using popBackStack:

FragmentManager fm = getActivity().getSupportFragmentManager();
fm.popBackStack();

Note this code came from an app of mine using the v4 support library, so the call for the fragment manager will be slightly different if you are developing for Android 3.0+ only.

Related Solutions

Android – How to save an activity state using the save instance state

You need to override onSaveInstanceState(Bundle savedInstanceState) and write the application state values you want to change to the Bundle parameter like this:

@Override
public void onSaveInstanceState(Bundle savedInstanceState) {
  super.onSaveInstanceState(savedInstanceState);
  // Save UI state changes to the savedInstanceState.
  // This bundle will be passed to onCreate if the process is
  // killed and restarted.
  savedInstanceState.putBoolean("MyBoolean", true);
  savedInstanceState.putDouble("myDouble", 1.9);
  savedInstanceState.putInt("MyInt", 1);
  savedInstanceState.putString("MyString", "Welcome back to Android");
  // etc.
}

The Bundle is essentially a way of storing a NVP ("Name-Value Pair") map, and it will get passed in to onCreate() and also onRestoreInstanceState() where you would then extract the values from activity like this:

@Override
public void onRestoreInstanceState(Bundle savedInstanceState) {
  super.onRestoreInstanceState(savedInstanceState);
  // Restore UI state from the savedInstanceState.
  // This bundle has also been passed to onCreate.
  boolean myBoolean = savedInstanceState.getBoolean("MyBoolean");
  double myDouble = savedInstanceState.getDouble("myDouble");
  int myInt = savedInstanceState.getInt("MyInt");
  String myString = savedInstanceState.getString("MyString");
}

Or from a fragment.

@Override
public void onViewStateRestored(@Nullable Bundle savedInstanceState) {
    super.onViewStateRestored(savedInstanceState);
    // Restore UI state from the savedInstanceState.
    // This bundle has also been passed to onCreate.
    boolean myBoolean = savedInstanceState.getBoolean("MyBoolean");
    double myDouble = savedInstanceState.getDouble("myDouble");
    int myInt = savedInstanceState.getInt("MyInt");
    String myString = savedInstanceState.getString("MyString");
}

You would usually use this technique to store instance values for your application (selections, unsaved text, etc.).

Android – Activity restart on rotation Android

Using the Application Class

Depending on what you're doing in your initialization you could consider creating a new class that extends Application and moving your initialization code into an overridden onCreate method within that class.

public class MyApplicationClass extends Application {
  @Override
  public void onCreate() {
    super.onCreate();
    // TODO Put your application initialization code here.
  }
}

The onCreate in the application class is only called when the entire application is created, so the Activity restarts on orientation or keyboard visibility changes won't trigger it.

It's good practice to expose the instance of this class as a singleton and exposing the application variables you're initializing using getters and setters.

NOTE: You'll need to specify the name of your new Application class in the manifest for it to be registered and used:

<application
    android:name="com.you.yourapp.MyApplicationClass"

Reacting to Configuration Changes [UPDATE: this is deprecated since API 13; see the recommended alternative]

As a further alternative, you can have your application listen for events that would cause a restart – like orientation and keyboard visibility changes – and handle them within your Activity.

Start by adding the android:configChanges node to your Activity's manifest node

 <activity android:name=".MyActivity"
      android:configChanges="orientation|keyboardHidden"
      android:label="@string/app_name">

or for Android 3.2 (API level 13) and newer:

<activity android:name=".MyActivity"
      android:configChanges="keyboardHidden|orientation|screenSize"
      android:label="@string/app_name">

Then within the Activity override the onConfigurationChanged method and call setContentView to force the GUI layout to be re-done in the new orientation.

@Override
public void onConfigurationChanged(Configuration newConfig) {
  super.onConfigurationChanged(newConfig);
  setContentView(R.layout.myLayout);
}

Best Answer

Related Solutions

Android – How to save an activity state using the save instance state

Android – Activity restart on rotation Android

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