Creating a timeline-based video list in Android requires combining RecyclerView with custom decorations to achieve a vertical chronological layout. This approach is commonly used in video editing applications, video galleries, and surveillance monitoring apps where time progression is visually important.

Core Implementation Components

To build a timeline video list, you need to address these key areas:

• Custom Layout Design: Create list items that accommodate video thumbnails, metadata (title, duration, timestamp), and timeline markers.
• Data Model: Define a model class holding video properties such as source URL, display name, duration, and timestamp.
• RecyclerView Adapter: Implement an adapter to bind video data to the list items.
• ItemDecoration: Draw the timeline axis and connecting lines between items.
• Thumbnail Loading: Use libraries like Glide or ExoPlayer to load video previews efficiently.

Adding Required Dependencies

Include the RecyclerView dependency in your module's build.gradle file:

dependencies {
    implementation 'androidx.recyclerview:recyclerview:1.3.2'
    implementation 'com.github.bumptech.glide:glide:4.16.0'
}

Designing the List Item Layout

Create res/layout/item_video_timeline.xml with a horizontal arrangement containing the timeline marker, thumbnail, and text information:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:padding="12dp">

    <!-- Timeline node -->
    <View
        android:id="@+id/timelineNode"
        android:layout_width="12dp"
        android:layout_height="12dp"
        android:background="@drawable/circle_accent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        android:layout_marginTop="8dp"/>

    <!-- Video thumbnail -->
    <ImageView
        android:id="@+id/imgThumbnail"
        android:layout_width="140dp"
        android:layout_height="100dp"
        android:layout_marginStart="16dp"
        android:scaleType="centerCrop"
        android:contentDescription="@string/video_thumbnail"
        app:layout_constraintStart_toEndOf="@id/timelineNode"
        app:layout_constraintTop_toTopOf="parent"/>

    <!-- Video title -->
    <TextView
        android:id="@+id/txtVideoTitle"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="12dp"
        android:textSize="16sp"
        android:textStyle="bold"
        android:maxLines="2"
        android:ellipsize="end"
        app:layout_constraintStart_toEndOf="@id/imgThumbnail"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="@id/imgThumbnail"/>

    <!-- Duration label -->
    <TextView
        android:id="@+id/txtDuration"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="4dp"
        android:textColor="#757575"
        android:textSize="13sp"
        app:layout_constraintStart_toStartOf="@id/txtVideoTitle"
        app:layout_constraintTop_toBottomOf="@id/txtVideoTitle"/>

</androidx.constraintlayout.widget.ConstraintLayout>

Creating the Data Model

Define a model class to represent each video entry:

public class VideoEntry {
    private String videoId;
    private String sourcePath;
    private String displayName;
    private long durationMillis;
    private long recordedAt;

    public VideoEntry(String videoId, String sourcePath, String displayName, 
                      long durationMillis, long recordedAt) {
        this.videoId = videoId;
        this.sourcePath = sourcePath;
        this.displayName = displayName;
        this.durationMillis = durationMillis;
        this.recordedAt = recordedAt;
    }

    // Getters
    public String getVideoId() { return videoId; }
    public String getSourcePath() { return sourcePath; }
    public String getDisplayName() { return displayName; }
    public long getDurationMillis() { return durationMillis; }
    public long getRecordedAt() { return recordedAt; }
}

Implementing the RecyclerView Adapter

Create an adapter that efficiently binds video data to the views:

public class TimelineVideoAdapter extends RecyclerView.Adapter<TimelineVideoAdapter.VideoHolder> {

    private final List<VideoEntry> videoEntries;
    private final OnVideoClickListener clickListener;

    public interface OnVideoClickListener {
        void onVideoClicked(VideoEntry entry, int position);
    }

    public TimelineVideoAdapter(List<VideoEntry> entries, OnVideoClickListener listener) {
        this.videoEntries = entries != null ? entries : new ArrayList<>();
        this.clickListener = listener;
    }

    @NonNull
    @Override
    public VideoHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        LayoutInflater inflater = LayoutInflater.from(parent.getContext());
        View itemView = inflater.inflate(R.layout.item_video_timeline, parent, false);
        return new VideoHolder(itemView);
    }

    @Override
    public void onBindViewHolder(@NonNull VideoHolder holder, int position) {
        VideoEntry entry = videoEntries.get(position);
        holder.bindData(entry, position);
    }

    @Override
    public int getItemCount() {
        return videoEntries.size();
    }

    class VideoHolder extends RecyclerView.ViewHolder {
        private final ImageView imgThumbnail;
        private final TextView txtVideoTitle;
        private final TextView txtDuration;

        VideoHolder(@NonNull View itemView) {
            super(itemView);
            imgThumbnail = itemView.findViewById(R.id.imgThumbnail);
            txtVideoTitle = itemView.findViewById(R.id.txtVideoTitle);
            txtDuration = itemView.findViewById(R.id.txtDuration);
        }

        void bindData(VideoEntry entry, int position) {
            txtVideoTitle.setText(entry.getDisplayName());
            txtDuration.setText(formatPlaybackTime(entry.getDurationMillis()));

            // Load thumbnail with Glide
            Glide.with(itemView.getContext())
                 .load(entry.getSourcePath())
                 .placeholder(R.drawable.ic_video_placeholder)
                 .centerCrop()
                 .into(imgThumbnail);

            itemView.setOnClickListener(v -> {
                if (clickListener != null) {
                    clickListener.onVideoClicked(entry, position);
                }
            });
        }

        private String formatPlaybackTime(long millis) {
            int seconds = (int) (millis / 1000);
            int minutes = seconds / 60;
            seconds = seconds % 60;
            return String.format(Locale.getDefault(), "%02d:%02d", minutes, seconds);
        }
    }
}

Creating the Timeline Decoration

Use ItemDecoration to draw the vertical timeline connecting all items:

public class TimelineItemDecoration extends RecyclerView.ItemDecoration {

    private final Paint linePaint;
    private final int nodeRadius;
    private final int timelineOffset;

    public TimelineItemDecoration(Context context) {
        nodeRadius = (int) (6 * context.getResources().getDisplayMetrics().density);
        timelineOffset = (int) (18 * context.getResources().getDisplayMetrics().density);

        linePaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        linePaint.setColor(Color.parseColor("#1976D2"));
        linePaint.setStrokeWidth(4f);
        linePaint.setStyle(Paint.Style.STROKE);
    }

    @Override
    public void onDraw(@NonNull Canvas canvas, @NonNull RecyclerView parent, 
                       @NonNull RecyclerView.State state) {
        super.onDraw(canvas, parent, state);

        int childCount = parent.getChildCount();
        if (childCount == 0) return;

        for (int i = 0; i < childCount; i++) {
            View child = parent.getChildAt(i);
            
            int left = timelineOffset;
            int top = child.getTop();
            int bottom = child.getBottom();

            // Draw vertical line
            canvas.drawLine(left, top, left, bottom, linePaint);
        }
    }

    @Override
    public void getItemOffsets(@NonNull Rect outRect, @NonNull View view, 
                               @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
        outRect.set(timelineOffset * 2, 0, 0, 0);
    }
}

Setting Up the RecyclerView

Configure the RecyclerView in your Activity or Fragment:

public class VideoTimelineActivity extends AppCompatActivity implements 
        TimelineVideoAdapter.OnVideoClickListener {

    private RecyclerView recyclerView;
    private TimelineVideoAdapter adapter;

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

        recyclerView = findViewById(R.id.recyclerViewTimeline);
        setupRecyclerView();
        loadVideoData();
    }

    private void setupRecyclerView() {
        adapter = new TimelineVideoAdapter(new ArrayList<>(), this);
        
        LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        layoutManager.setOrientation(LinearLayoutManager.VERTICAL);

        recyclerView.setLayoutManager(layoutManager);
        recyclerView.setAdapter(adapter);
        recyclerView.addItemDecoration(new TimelineItemDecoration(this));
    }

    private void loadVideoData() {
        List<VideoEntry> sampleVideos = generateSampleData();
        adapter = new TimelineVideoAdapter(sampleVideos, this);
        recyclerView.setAdapter(adapter);
    }

    private List<VideoEntry> generateSampleData() {
        List<VideoEntry> entries = new ArrayList<>();
        // Add sample video entries
        entries.add(new VideoEntry("1", "/path/video1.mp4", "Morning Walk", 125000, 
                                   System.currentTimeMillis()));
        entries.add(new VideoEntry("2", "/path/video2.mp4", "Meeting Recording", 360000, 
                                   System.currentTimeMillis()));
        return entries;
    }

    @Override
    public void onVideoClicked(VideoEntry entry, int position) {
        // Handle video click - open detail or play video
        Intent intent = new Intent(this, VideoDetailActivity.class);
        intent.putExtra("VIDEO_PATH", entry.getSourcePath());
        startActivity(intent);
    }
}

For advanced scenarios, consider adding video preview functionality using ExoPlayer to display frame-by-frame previews when users long-press on timeline items.