PrecomputedText

Kotlin |Java

open class PrecomputedText : Spannable

kotlin.Any
↳	android.text.PrecomputedText

A text which has the character metrics data. A text object that contains the character metrics data and can be used to improve the performance of text layout operations. When a PrecomputedText is created with a given CharSequence, it will measure the text metrics during the creation. This PrecomputedText instance can be set on android.widget.TextView or StaticLayout. Since the text layout information will be included in this instance, android.widget.TextView or StaticLayout will not have to recalculate this information. Note that the PrecomputedText created from different parameters of the target android.widget.TextView will be rejected internally and compute the text layout again with the current android.widget.TextView parameters.

An example usage is:
  <code>
   static void asyncSetText(TextView textView, final String longString, Executor bgExecutor) {
       // construct precompute related parameters using the TextView that we will set the text on.
       final PrecomputedText.Params params = textView.getTextMetricsParams();
       final Reference textViewRef = new WeakReference&lt;&gt;(textView);
       bgExecutor.submit(() -&gt; {
           TextView textView = textViewRef.get();
           if (textView == null) return;
           final PrecomputedText precomputedText = PrecomputedText.create(longString, params);
           textView.post(() -&gt; {
               TextView textView = textViewRef.get();
               if (textView == null) return;
               textView.setText(precomputedText);
           });
       });
   }
  </code>

Note that the PrecomputedText created from different parameters of the target android.widget.TextView will be rejected. Note that any android.text.NoCopySpan attached to the original text won't be passed to PrecomputedText.

Summary

Nested classes
	`Params` The information required for building `PrecomputedText`.

Public methods
open static PrecomputedText!	`create(text: CharSequence, params: PrecomputedText.Params)` Create a new `PrecomputedText` which will pre-compute text measurement and glyph positioning information.
open Char	`get(index: Int)` Returns the `char` value at the specified index.
open Unit	`getBounds(start: Int, end: Int, bounds: Rect)` Retrieves the text bounding box for the given range.
open Unit	`getFontMetricsInt(start: Int, end: Int, outMetrics: Paint.FontMetricsInt)` Retrieves the text font metrics for the given range.
open Int	`getParagraphCount()` Returns the count of paragraphs.
open Int	`getParagraphEnd(paraIndex: Int)` Returns the paragraph end offset of the text.
open Int	`getParagraphStart(paraIndex: Int)` Returns the paragraph start offset of the text.
open PrecomputedText.Params	`getParams()` Returns the layout parameters used to measure this text.
open Int	`getSpanEnd(tag: Any!)` Return the end of the range of text to which the specified markup object is attached, or -1 if the object is not attached.
open Int	`getSpanFlags(tag: Any!)` Return the flags that were specified when `Spannable.setSpan` was used to attach the specified markup object, or 0 if the specified object has not been attached.
open Int	`getSpanStart(tag: Any!)` Return the beginning of the range of text to which the specified markup object is attached, or -1 if the object is not attached.
open Array<T>!	`getSpans(start: Int, end: Int, type: Class<T>!)` Return an array of the markup objects attached to the specified slice of this CharSequence and whose type is the specified type or a subclass of it.
open Float	`getWidth(start: Int, end: Int)` Returns text width for the given range.
open Int	`nextSpanTransition(start: Int, limit: Int, type: Class<Any!>!)` Return the first offset greater than `start` where a markup object of class `type` begins or ends, or `limit` if there are no starts or ends greater than `start` but less than `limit`.
open Unit	`removeSpan(what: Any!)`
open Unit	`setSpan(what: Any!, start: Int, end: Int, flags: Int)`
open CharSequence	`subSequence(startIndex: Int, endIndex: Int)` Returns a `CharSequence` that is a subsequence of this sequence.
open String	`toString()` Returns a string representation of the object.

Properties
open Int	`length` Returns the length of this character sequence.

Parameters
`text`	CharSequence: the text to be measured. This value cannot be `null`.
`params`	PrecomputedText.Params: parameters that define how text will be precomputed. This value cannot be `null`.

Parameters
`start`	Int: the inclusive start offset in the text. Value is 0 or greater
`end`	Int: the exclusive end offset in the text. Value is 0 or greater
`bounds`	Rect: the output rectangle. This value cannot be `null`.

Parameters
`start`	the start index, inclusive
`end`	the end index, exclusive

PrecomputedText

Summary

Public methods

create

get

getBounds

getFontMetricsInt

getParagraphCount

getParagraphEnd

getParagraphStart

getParams

getSpanEnd

getSpanFlags

getSpanStart

getSpans

getWidth

nextSpanTransition

removeSpan

setSpan

subSequence

toString

Properties

length