Add a workaround for text being measured incorrectly when ending with an empty line (#42331)

Summary:
It looks like `StaticLayout` used for measuring multiline text on the new architecture returns wrong metrics for the last line if it's empty, however, if it contains anything, then the returned values are correct.

Similar approach with measuring `I` was already used in `ReactEditText`: https://github.com/facebook/react-native/blob/258d8e51b451b221e557dad4647cbd210fe37392/packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/textinput/ReactEditText.java#L1203-L1213

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[ANDROID] [FIXED] - Fixed text being measured incorrectly when ending with an empty line on the new architecture

Pull Request resolved: https://github.com/facebook/react-native/pull/42331

Test Plan:
<details>
<summary>I tested the change on this simple code on React Native 0.73.2 (with the new arch enabled)</summary>

```jsx
import React from 'react';
import {useState} from 'react';
import {SafeAreaView, TextInput} from 'react-native';

export default function App() {
  const [text, setText] = useState('ABC\nDEF\nGHI\n');

  return (
    <SafeAreaView style={{flex: 1}}>
      <TextInput
        value={text}
        onChangeText={setText}
        style={{borderWidth: 1, margin: 20, padding: 30}}
        multiline
      />
    </SafeAreaView>
  );
}
```

</details>

Before:

https://github.com/facebook/react-native/assets/21055725/0787cc86-70c6-4238-b93a-87984e527a83

After:

https://github.com/facebook/react-native/assets/21055725/2acf619f-5cb4-4869-9576-cb8cc081c15b

Reviewed By: cipolleschi

Differential Revision: D62873674

Pulled By: cortinico

fbshipit-source-id: cc2481b1924a13af7326cfc16c59b9390f0d06d8
This commit is contained in:
Jakub Piasecki authored and Facebook GitHub Bot committed 2024-09-21 06:34:21 -07:00
1 parent 1747f57c67
commit bd323929dc
1 file changed
+9
@@ -355,6 +355,15 @@ public class TextLayoutManager {
int hyphenationFrequency,
Layout.Alignment alignment) {
Layout layout;
// StaticLayout returns wrong metrics for the last line if it's empty, add something to the
// last line so it's measured correctly
if (text.toString().endsWith("\n")) {
SpannableStringBuilder sb = new SpannableStringBuilder(text);
sb.append("I");
text = sb;
}
int spanLength = text.length();
boolean unconstrainedWidth = widthYogaMeasureMode == YogaMeasureMode.UNDEFINED || width < 0;
float desiredWidth =