Android Dialog Example (AlertDialog, Custom Dialog & DialogFragment)

Dialogs in Android are used to display short, focused interactions that require user input or confirmation. In modern Android development, dialogs should follow Material Design guidelines and be lifecycle-aware to prevent memory leaks and crashes.

This guide on javatechig.com explains how to implement:

• AlertDialog (Recommended approach)
• Custom Dialog with custom layout
• DialogFragment (Lifecycle-safe implementation)
• Best practices for modern Android (API 34+)

Understanding Dialogs in Modern Android

A dialog is a small window that prompts the user to make a decision or enter additional information.

Common use cases:

• Confirmation prompts (Delete, Exit, Logout)
• Form input
• Selection lists
• Error messages

⚠ Avoid using deprecated ProgressDialog. Use progress indicators inside layouts instead.

AlertDialog Example (Recommended Approach)

AlertDialog is the most commonly used dialog type.

Kotlin Implementation (Preferred)

val builder = AlertDialog.Builder(this)
builder.setTitle("Delete Item")
builder.setMessage("Are you sure you want to delete this item?")
builder.setPositiveButton("Yes") { dialog, _ ->
    // Perform delete action
    dialog.dismiss()
}
builder.setNegativeButton("Cancel") { dialog, _ ->
    dialog.dismiss()
}

val dialog = builder.create()
dialog.show()

Java Implementation

AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Delete Item");
builder.setMessage("Are you sure you want to delete this item?");

builder.setPositiveButton("Yes", (dialog, which) -> {
    dialog.dismiss();
});

builder.setNegativeButton("Cancel", (dialog, which) -> {
    dialog.dismiss();
});

AlertDialog dialog = builder.create();
dialog.show();

Adding Material Design Styling (Recommended)

To use Material Design dialogs, ensure your app theme extends:

Theme.Material3.DayNight.NoActionBar

Then use:

MaterialAlertDialogBuilder(this)

Instead of AlertDialog.Builder.

Example:

MaterialAlertDialogBuilder(this)
    .setTitle("Logout")
    .setMessage("Do you really want to logout?")
    .setPositiveButton("Yes") { dialog, _ ->
        dialog.dismiss()
    }
    .setNegativeButton("No", null)
    .show()

This follows official Material standards from Android guidelines.

Custom Dialog Example (Using Custom Layout)

Use a custom dialog when you need:

• Form input
• Custom UI
• Complex interactions

Step 1: Create Layout (dialog_custom.xml)

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:padding="20dp"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <EditText
        android:id="@+id/etName"
        android:hint="Enter Name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

</LinearLayout>

Step 2: Inflate and Show Dialog

val view = layoutInflater.inflate(R.layout.dialog_custom, null)
val editText = view.findViewById<EditText>(R.id.etName)

MaterialAlertDialogBuilder(this)
    .setTitle("Input Required")
    .setView(view)
    .setPositiveButton("Submit") { dialog, _ ->
        val name = editText.text.toString()
        dialog.dismiss()
    }
    .setNegativeButton("Cancel", null)
    .show()

DialogFragment (Lifecycle-Safe Implementation)

Using DialogFragment is the recommended approach for:

• Configuration changes (rotation)
• Fragment-based architecture
• Preventing window leaks

Create DialogFragment Class

class ConfirmDialog : DialogFragment() {

    override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
        return MaterialAlertDialogBuilder(requireContext())
            .setTitle("Confirm")
            .setMessage("Proceed with action?")
            .setPositiveButton("Yes") { dialog, _ ->
                dialog.dismiss()
            }
            .setNegativeButton("Cancel", null)
            .create()
    }
}

Show DialogFragment

ConfirmDialog().show(supportFragmentManager, "ConfirmDialog")

This approach prevents WindowLeaked errors.

Dialog with List Items Example

val items = arrayOf("Option 1", "Option 2", "Option 3")

MaterialAlertDialogBuilder(this)
    .setTitle("Choose Option")
    .setItems(items) { dialog, which ->
        val selected = items[which]
        dialog.dismiss()
    }
    .show()

Common Mistakes to Avoid

1. Using Activity Context After Finish()

Always ensure:

!isFinishing

Before showing dialog in Activity.

2. Memory Leaks with Anonymous Classes

Prefer lifecycle-aware components like DialogFragment.

3. Blocking UI Thread

Never run heavy tasks inside dialog button listeners.

Best Practices (2026 Updated)

• Use MaterialAlertDialogBuilder for consistency
• Prefer DialogFragment for complex flows
• Avoid deprecated APIs
• Handle configuration changes properly
• Keep dialogs short and focused
• Use ViewBinding inside custom dialogs
• Do not overuse dialogs (UX guideline)

When to Use Dialog vs Bottom Sheet

Use Dialog when:

• Immediate confirmation required
• Small interaction

Use BottomSheet when:

• Multiple actions
• Rich UI interaction
• Modern UX preference