Android Intents: Camera, Activities and Fragments

Part 1: Intents, camera and images

Create a form that captures a text field and a picture. The picture could be captured using the device's camera or selected from the images stored on the device. In order to give the options to the user you should use a single choice AlertDialog.

     @NonNull
        public static Dialog createSingleChoiceAlertDialog( @NonNull Context context, @Nullable String title,
                                                            @NonNull CharSequence[] items,
                                                            @NonNull DialogInterface.OnClickListener optionSelectedListener,
                                                            @Nullable DialogInterface.OnClickListener cancelListener )
        {
            AlertDialog.Builder builder = new AlertDialog.Builder( context, R.style.My_Dialog );
            builder.setItems( items, optionSelectedListener );
            if ( cancelListener != null )
            {
                builder.setNegativeButton( R.string.Cancel, cancelListener );
            }
            builder.setTitle( title );
            return builder.create();
        }

Once the user selects an image it should be displayed in the form (as shown on the screenshot as the Android icon).

Form Validation Criteria:

• If the text is empty and no image is selected the following message should be displayed to the user “Please enter either a message or select an image”.
• The text field should have a length longer than 50 characters.

Note: You can use the method setError method of the EditText object to display the error message to the user.

Part 2: Activities Intents

1. Create a POJO that represents a Post that will contain the data captured in the form (message and imageUri). Make sure the Post class implements the Serializable interface.

2. Create a second Activity named PostActivity that will display the saved post. Make sure you include this activity on your AndroidManifest.xml file, otherwise you won't be able to start the PostActivity.

3. Create a method that handles the save button onClick event. This method should first trigger the form validation and if the validation is correct then:

• Create a new intent for the PostActivity created before.
• Create a Bundle object and add the Post object created to this bundle, then add the bundle to the intent as extras.
• Start the new activity using the intent.

This documentation will help you:

https://developer.android.com/training/basics/firstapp/starting-activity.html

Part 3: Using Fragments

1. Create a Fragment called NewPostFragment. This should extend the class Support Fragment and contain the same layout and code that you have in the MainActivity to handle the form that captures the photo and a message.

2. Modify the layout of the main activity to have only a Framelayout that fills all the space and has the id fragment_container

3. Create another Fragment that contains the logic and layout of the PostActivity called PostFragment

4. Modify your MainActivity and make sure that after the activity is created then your show the NewPostFragment using the following code:

   public void showFragment( Fragment fragment, boolean addToBackStack)
    {
        FragmentManager fragmentManager = getSupportFragmentManager();
        FragmentTransaction transaction = fragmentManager.beginTransaction();
    
        String tag = fragment.getClass().getSimpleName();
        if ( addToBackStack )
        {
            transaction.addToBackStack( tag );
        }
        transaction.replace( R.id.fragment_container, fragment, tag );
        transaction.commitAllowingStateLoss();
    }

5. Modify the MainActivity so when you click on save you show the PostFragment

6. Verify that the App works as before when you had only activities.