Paginating Text in Android
Problem:
Paginating text within a TextView control in Android requires determining when and how to break the text into pages. This can be challenging as TextView's line-breaking and page-breaking algorithms are not readily accessible, making it difficult to identify where the text ends on the actual display.
Solution:
By monitoring the visible text range using the ViewTreeObserver, it is possible to track the last line that fully fits within the view's height. This allows for the creation of pages based on the cumulative height of the lines, ensuring that pages are broken when a line is encountered that exceeds the available vertical space.
Algorithm:
Implementation:
To implement this algorithm, use the following code:
// Setup code ViewTreeObserver vto = txtViewEx.getViewTreeObserver(); vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener() { @Override public void onGlobalLayout() { ViewTreeObserver obs = txtViewEx.getViewTreeObserver(); obs.removeOnGlobalLayoutListener(this); height = txtViewEx.getHeight(); scrollY = txtViewEx.getScrollY(); Layout layout = txtViewEx.getLayout(); firstVisibleLineNumber = layout.getLineForVertical(scrollY); lastVisibleLineNumber = layout.getLineForVertical(height + scrollY); } });
Note:
This solution efficiently paginates text while respecting line height and character spacing. It also handles special characters and dynamic text changes.
The above is the detailed content of How to Paginate Text within a TextView Control in Android?. For more information, please follow other related articles on the PHP Chinese website!