A powerful extended official text for Flutter

extended_text

extended official text to build special text like inline image or @somebody quickly,it also support custom background,custom over flow and custom selection toolbar and handles.

speical text

create speical text

extended text helps to convert your text to speical textspan quickly.

for example, follwing code show how to create @xxxx speical textspan.

class attext extends specialtext {
  attext(textstyle textstyle, specialtextgesturetapcallback ontap,
      {this.showatbackground = false, this.start})
      : super(flag, ' ', textstyle, ontap: ontap);
  static const string flag = '@';
  final int start;

  /// whether show background for @somebody
  final bool showatbackground;

  @override
  inlinespan finishtext() {
    final textstyle textstyle =
        this.textstyle?.copywith(color: colors.blue, fontsize: 16.0);

    final string attext = tostring();

    return showatbackground
        ? backgroundtextspan(
            background: paint()..color = colors.blue.withopacity(0.15),
            text: attext,
            actualtext: attext,
            start: start,

            ///caret can move into special text
            deleteall: true,
            style: textstyle,
            recognizer: (tapgesturerecognizer()
              ..ontap = () {
                if (ontap != null) {
                  ontap(attext);
                }
              }))
        : specialtextspan(
            text: attext,
            actualtext: attext,
            start: start,
            style: textstyle,
            recognizer: (tapgesturerecognizer()
              ..ontap = () {
                if (ontap != null) {
                  ontap(attext);
                }
              }));
  }
}

specialtextspanbuilder

create your specialtextspanbuilder

class myspecialtextspanbuilder extends specialtextspanbuilder {
  myspecialtextspanbuilder({this.showatbackground = false});

  /// whether show background for @somebody
  final bool showatbackground;
  @override
  textspan build(string data,
      {textstyle textstyle, specialtextgesturetapcallback ontap}) {
    if (kisweb) {
      return textspan(text: data, style: textstyle);
    }

    return super.build(data, textstyle: textstyle, ontap: ontap);
  }

  @override
  specialtext createspecialtext(string flag,
      {textstyle textstyle, specialtextgesturetapcallback ontap, int index}) {
    if (flag == null || flag == '') {
      return null;
    }

    ///index is end index of start flag, so text start index should be index-(flag.length-1)
    if (isstart(flag, attext.flag)) {
      return attext(
        textstyle,
        ontap,
        start: index - (attext.flag.length - 1),
        showatbackground: showatbackground,
      );
    } else if (isstart(flag, emojitext.flag)) {
      return emojitext(textstyle, start: index - (emojitext.flag.length - 1));
    } else if (isstart(flag, dollartext.flag)) {
      return dollartext(textstyle, ontap,
          start: index - (dollartext.flag.length - 1));
    }
    return null;
  }
}

image

imagespan

show inline image by using imagespan.

class imagespan extends extendedwidgetspan {
  imagespan(
    imageprovider image, {
    key key,
    @required double imagewidth,
    @required double imageheight,
    edgeinsets margin,
    int start = 0,
    ui.placeholderalignment alignment = ui.placeholderalignment.bottom,
    string actualtext,
    textbaseline baseline,
    boxfit fit= boxfit.scaledown,
    imageloadingbuilder loadingbuilder,
    imageframebuilder framebuilder,
    string semanticlabel,
    bool excludefromsemantics = false,
    color color,
    blendmode colorblendmode,
    alignmentgeometry imagealignment = alignment.center,
    imagerepeat repeat = imagerepeat.norepeat,
    rect centerslice,
    bool matchtextdirection = false,
    bool gaplessplayback = false,
    filterquality filterquality = filterquality.low,
    gesturetapcallback ontap,
    hittestbehavior behavior = hittestbehavior.defertochild,
  })

selection

textselectioncontrols

default value of textselectioncontrols are materialextendedtextselectioncontrols/cupertinoextendedtextselectioncontrols

override buildtoolbar or buildhandle to custom your toolbar widget or handle widget

class myextendedmaterialtextselectioncontrols
    extends extendedmaterialtextselectioncontrols {
  myextendedmaterialtextselectioncontrols();
  @override
  widget buildtoolbar(
    buildcontext context,
    rect globaleditableregion,
    double textlineheight,
    offset selectionmidpoint,
    list<textselectionpoint> endpoints,
    textselectiondelegate delegate,
  ) {}

  @override
  widget buildhandle(
      buildcontext context, textselectionhandletype type, double textheight) {
  }
}

control toolbar handle

contain your page into extendedtextselectionpointerhandler, so you can control toolbar and handle.

default behavior

set your page as child of extendedtextselectionpointerhandler

 return extendedtextselectionpointerhandler(
      //default behavior
       child: result,
    );

• tap region outside of extended text, hide toolbar and handle
• scorll, hide toolbar and handle

custom behavior

get selectionstates(extendedtextselectionstate) by builder call back, and handle by your self.

 return extendedtextselectionpointerhandler(
      //default behavior
      // child: result,
      //custom your behavior
      builder: (states) {
        return listener(
          child: result,
          behavior: hittestbehavior.translucent,
          onpointerdown: (value) {
            for (var state in states) {
              if (!state.containsposition(value.position)) {
                //clear other selection
                state.clearselection();
              }
            }
          },
          onpointermove: (value) {
            //clear other selection
            for (var state in states) {
              state.clearselection();
            }
          },
        );
      },
    );

custom background

refer to issues 24335/24337 about background

  backgroundtextspan(
      text:
          "this text has nice background with borderradius,no mattter how many line,it likes nice",
      background: paint()..color = colors.indigo,
      clipborderradius: borderradius.all(radius.circular(3.0))),

custom overflow

refer to issue 26748

  extendedtext(
   overflowwidget: textoverflowwidget(
     position: textoverflowposition.end,
     align: textoverflowalign.center,
     // just for debug
     debugoverflowrectcolor: colors.red.withopacity(0.1),
     child: container(
       child: row(
         mainaxissize: mainaxissize.min,
         children: <widget>[
           const text('u2026 '),
           inkwell(
             child: const text(
               'more',
             ),
             ontap: () {
               launch(
                   'https://github.com/fluttercandies/extended_text');
             },
           )
         ],
       ),
     ),
   ),
  )

join zero-width space

refer to issue 18761

if [extendedtext.joinzerowidthspace] is true, it will join ‘u{200b}’ into text, make line breaking and overflow style better.

  extendedtext(
      joinzerowidthspace: true,
    )

or you can convert by following method:

1. string

  string input='abc'.joinchar();

2. inlinespan

     inlinespan innertextspan;
     innertextspan = joinchar(
        innertextspan,
        accumulator(),
        zerowidthspace,
    );

take care of following things:

1. the word is not a word, it will not working when you want to double tap to select a word.
2. text is changed, if [extendedtext.selectionenabled] is true, you should override textselectioncontrols and remove zerowidthspace.

class mytextselectioncontrols extends textselectioncontrols {

  @override
  void handlecopy(textselectiondelegate delegate,
      clipboardstatusnotifier? clipboardstatus) {
    final texteditingvalue value = delegate.texteditingvalue;

    string data = value.selection.textinside(value.text);
    // remove zerowidthspace
    data = data.replaceall(zerowidthspace, '');

    clipboard.setdata(clipboarddata(
      text: value.selection.textinside(value.text),
    ));
    clipboardstatus?.update();
    delegate.texteditingvalue = texteditingvalue(
      text: value.text,
      selection: textselection.collapsed(offset: value.selection.end),
    );
    delegate.bringintoview(delegate.texteditingvalue.selection.extent);
    delegate.hidetoolbar();
  }
}