How Can We Achieve Accurate Pagination in Android TextView?

Paginating Text in Android

Background

Traditional pagination in Android using TextView faces challenges in accurately determining where content ends on the actual display. This hinders efficient navigation between pages.

The Algorithm

Step 1: Initialize Variables

• Calculate the view's height (height) and vertical scroll position (scrollY)
• Obtain the Layout object associated with the TextView

Step 2: Determine Visible Text Lines

• firstVisibleLineNumber and lastVisibleLineNumber represent the first and last visible lines in the TextView

Step 3: Paginate Text

• Iterate through the lines of text.
• When the bottom of a line exceeds height, create a new page and calculate a new cumulative height (height) for comparing with the bottom of the next line.

Implementation Notes:

• Uses the StaticLayout class for text layout with line breaking.
• Considers both character-based and image-based text.
• Supports dynamic changes in TextView attributes and algorithm parameters.
• Offers optimization for text with uniform line height.

Sample Code

val text = "Your text here"
val viewWidth = textView.width
val viewHeight = textView.height
val pagination = Pagination(text, viewWidth, viewHeight, textView.paint)
val pages = pagination.getPages()

Advantages

• Accurate pagination, capturing all visible text
• Customizable for different text formats and sizes
• Efficient and dynamic, allowing for real-time updates

Considerations

• May not be suitable for highly complex text layouts or when precise character placement is critical
• Performance may vary depending on the amount of text and layout complexity

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