Android/Kotlin: How to show an activity as a popup/dialog when clicking on a card from a recyclerview?

Question

I've searched for it everywhere but I didn't found a satisfying answer yet. So, I'd would like to know: How to show an activity as a popup/dialog when clicking on a card from a recyclerview? Is it made straight through the adapter? Do I need a second activity to do that or just another layout.xml is enough?

I've tried:

android:theme="@style/Theme.AppCompat.Dialog"

But it's throwing the following error everytime I click on the card from the recyclerview:

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.softdevandre.marvelapi/com.softdevandre.marvelapi.ui.DetailCharacterActivity}: android.view.InflateException: Binary XML file line #11 in com.softdevandre.marvelapi:layout/activity_detail_character: Binary XML file line #11 in com.softdevandre.marvelapi:layout/activity_detail_character: Error inflating class <unknown>

AndroidManifest.xml:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
package="com.softdevandre.marvelapi" >

    <application
        android:allowBackup="true"
        android:dataExtractionRules="@xml/data_extraction_rules"
        android:fullBackupContent="@xml/backup_rules"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.MarvelAPI"
        tools:targetApi="31" >
        <activity
            android:name=".ui.DetailCharacterActivity"
            android:theme="@style/Theme.AppCompat.Dialog"
            android:autoRemoveFromRecents="true"
            android:parentActivityName=".MainActivity"
            android:exported="false" >
            <meta-data
                android:name="android.app.lib_name"
                android:value="" />
        </activity>
        <activity
            android:name=".MainActivity"
            android:exported="true" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

activity_detail_character.xml:

<?xml version="1.0" encoding="utf-8"?>
<com.google.android.material.card.MaterialCardView
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="255dp"
    android:layout_margin="8dp"
    app:cardElevation="5dp"
    app:cardCornerRadius="8dp"
    tools:context=".ui.DetailCharacterActivity">

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <androidx.appcompat.widget.AppCompatImageView
            android:id="@+id/ivCharacter"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:scaleType="centerCrop"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            tools:ignore="ImageContrastCheck"
            tools:srcCompat="@tools:sample/avatars" />

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical"
            android:background="#80CC0000"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent">

            <com.google.android.material.textview.MaterialTextView
                android:id="@+id/tvCharacterName"
                android:layout_width="match_parent"
                android:textColor="@color/white"
                android:gravity="center"
                android:layout_height="match_parent"
                android:layout_marginStart="12dp"
                android:layout_marginBottom="12dp"
                android:layout_marginEnd="12dp"
                android:layout_marginTop="8dp"
                android:textSize="16sp"
                android:textStyle="bold"
                tools:text="Character Name" />

        </LinearLayout>

    </androidx.constraintlayout.widget.ConstraintLayout>
</com.google.android.material.card.MaterialCardView>

ItemCharacterAdapter.kt:

class ItemCharacterAdapter(private val context: Context, private val dataset: List<Characters>) :
    RecyclerView.Adapter<ItemCharacterAdapter.CharacterViewHolder>() {

    class CharacterViewHolder(binding: ItemCharacterBinding) :
        RecyclerView.ViewHolder(binding.root) {
        val textView: TextView = binding.tvCharacterName
        val imageView: ImageView = binding.ivCharacter
        val materialCard: MaterialCardView = binding.mcvCharacter
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): CharacterViewHolder {
        // create new view
        val adapterLayout =
            ItemCharacterBinding.inflate(LayoutInflater.from(parent.context), parent, false)
        return CharacterViewHolder(adapterLayout)
    }

    override fun onBindViewHolder(holder: CharacterViewHolder, position: Int) {
        val item = dataset[position]
        holder.textView.text = context.resources.getString(item.name)
        holder.imageView.setImageResource(item.image)
        holder.materialCard.setOnClickListener {
            val intent = Intent(context, DetailCharacterActivity::class.java)
            context.startActivity(intent)
        }
    }

    override fun getItemCount() = dataset.size
}

MainActivity.kt:

class MainActivity : AppCompatActivity() {

    private val binding by lazy {
        ActivityMainBinding.inflate(layoutInflater)
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(binding.root)

        val myDataset = Datasource().loadCharacters()

        val recyclerView = binding.rvCharacterList
        recyclerView.adapter = ItemCharacterAdapter(this, myDataset)

    }
}

Thanks in advance.

Answer 1

To start activity as dialog defined it like this in AndroidManifest.xml:

<activity android:theme="@android:style/Theme.Dialog" />

Use this property inside your activity tag to avoid that your Dialog appears in the recently used apps list

android:excludeFromRecents="true"

If you want to stop your dialog / activity from being destroyed when the user clicks outside of the dialog:

After setContentView() in your Activity use:

this.setFinishOnTouchOutside(false);

Now, call startActivity() on your recycler view card click it displays as a dialog, with the previous activity shown when the user presses the back button.

Note that if you are using ActionBarActivity (or AppCompat theme), you'll need to use @style/Theme.AppCompat.Dialog instead.