To optimize TextView performance in large layouts, you must address the fact that measuring and rendering text can take up to 90% of the total time required to draw a view. When complex text is placed inside heavily nested layouts, it causes multiple layout passes, resulting in dropped frames and a laggy user experience. 1. Offload Calculations with PrecomputedText
By default, text measurement occurs entirely on the Main UI Thread during the layout phase. PrecomputedText allows you to compute text layout metrics (like font metrics, line-breaking, and hyphenation) on a background thread before displaying it.
Use PrecomputedTextCompat: Create the text layout parameters on the main thread, shift the heavy lifting to a background coroutine, and then set the text back on the main thread.
fun TextView.setTextAsync(text: String) { val textView = this (context as? AppCompatActivity)?.lifecycleScope?.launch { // 1. Get metrics from the TextView on the Main Thread val params = TextViewCompat.getTextMetricsParams(textView) // 2. Compute the text layout on a Background Thread val precomputedText = withContext(Dispatchers.Default) { PrecomputedTextCompat.create(text, params) } // 3. Set the precomputed text on the Main Thread TextViewCompat.setPrecomputedText(textView, precomputedText) } } Use code with caution.
Match text parameters exactly: If the target TextView properties (like textSize, typeface, or breakStrategy) change after computing, the system will throw an exception or recalculate from scratch. 2. Flatten Your View Hierarchy
When a TextView contains dynamic text or uses wrap_content, any text change triggers a recalculation that ripples up to the parent layout. Deeply nested layouts worsen this effect significantly.
Switch to ConstraintLayout: Replace nested LinearLayout or RelativeLayout structures with a single ConstraintLayout to achieve a flat hierarchy.
Avoid nested weights: LinearLayout views using layout_weight require a costly double-layout pass to calculate final sizes.
Use Compound Drawables: Instead of nesting an ImageView next to a TextView inside a parent layout, handle them inside a single TextView using android:drawableStart or android:drawableEnd. 3. Minimize Text Layout Complexity
Certain configuration settings force the system to perform complex computations every time the text is measured.
Disable Font Padding: Set android:includeFontPadding=“false”. This removes extra top and bottom spacing reserved for accents, speeding up measurement and making spacing predictable.
Control Hyphenation: Hyphenation calculations are mathematically heavy. In Android 10 (API 29) and higher, it is turned off by default. For older versions or custom configurations, ensure it is disabled or minimized unless strictly necessary: android:hyphenationFrequency=“none” Use code with caution.
Avoid excessive Break Strategies: Avoid using android:breakStrategy=“high_quality” on large, dynamic text structures because it maximizes line-breaking optimization at the cost of processing speed. Stick to “simple” for performance-critical views. 4. Optimize Dynamic & Paginated Content
Loading thousands of words into a single TextView will eventually overflow memory and freeze the UI thread.
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