指定宽度截取字符串的函数_截取某个字符之前的字符串[通俗易懂]

开发过程中遇到一个需求,就是在聊天栏中,对于超出聊天框的文字需要省略并添加省略号,比如输入”dasda这是一个例子にほんçai222!]]//*”,需要截取并显示为”dasda这是一个例子にほんç…”,注意:字符串长度不等于字符串宽度,以下提供两种情况的代码,第一种是纯C#调用,第二种是Lua和C#

①C#

//获取字符串宽度
public float GetWidth(Text textComponent, string textContent)
{
    Text text = textComponent;
    Font font = text.font;
    if (font == null)
    {
        return 0;
    }
    int fontSize = font.fontSize;
    FontStyle fontStyle = text.fontStyle;
    font.RequestCharactersInTexture(textContent, fontSize, fontStyle);
    CharacterInfo characterInfo;
    float width = 0f;
    for (int i = 0; i < textContent.Length; i++)
    {
        font.GetCharacterInfo(textContent[i], out characterInfo, fontSize);
        width += characterInfo.advance;
    }
    return width;
}

//拆分字符串
public Array SplitString(string s)
{
    char[] strCharArr = s.ToCharArray();
    return strCharArr;
}

//获取允许显示的文本内容  textContent = '这是一个参数示例', textComponent = self.Text.chatTxt1, widthOriginal = 393, textTarget = '...'
//textContent:原文本内容
//textComponent:text组件
//widthOriginal:text组件节点的width(通过直接传入这个值, 来避免在此方法内频繁调用GetComponent)
//widthTarget:想要显示的区域宽度(比如省略号宽度10, 那width就是10)和textTarget二选一传入
//textTarget:想要添加的字符串(比如添加省略号'...')和widthTarget二选一传入
//示例功能详见hud界面左下角的聊天栏
public string GetShowText(string textContent,Text textComponent,float widthOriginal,float widthTarget = 0,string textTarget = "")
{
    if (widthTarget == 0 && !textTarget.Equals(""))
    {
        widthTarget = GetWidth(textComponent, textTarget);
    }
    float tempWidth = 0;
    string stringTemp = string.Empty;
    string stringTarget = string.Empty;
    Array tab = SplitString(textContent);
    for (int i = 0; i < tab.Length - 1; i++)
    {
        stringTarget = stringTemp;
        stringTemp = stringTemp + tab.GetValue(i);
        tempWidth = GetWidth(textComponent, stringTemp);
        if ((widthTarget + tempWidth) >= widthOriginal)
        {
            break;
        }
    }
    if ((widthTarget + tempWidth) >= widthOriginal)
    {
        if (!textTarget.Equals(""))
        {
            stringTarget = stringTarget + textTarget;
        }
    }
    else
    {
        stringTarget = stringTemp;
    }
    return stringTarget;
}

private void Start()
{
    string sss = GetShowText("dasda这是一个例子にほんçai222!]]//*", this.GetComponent<Text>(), 100, 0 ,"...");
    this.GetComponent<Text>().text = sss;
}

②Lua&C#

//获取字符串宽度
public float GetWidth(string textContent)
{
    Text text = this.GetComponent<Text>();
    Font font = text.font;
    if (font == null)
    {
        return 0;
    }
    int fontSize = font.fontSize;
    FontStyle fontStyle = text.fontStyle;
    font.RequestCharactersInTexture(textContent, fontSize, fontStyle);
    CharacterInfo characterInfo;
    float width = 0f;
    for (int i = 0; i < textContent.Length; i++)
    {
        font.GetCharacterInfo(textContent[i], out characterInfo, fontSize);
        width += characterInfo.advance;
    }
    return width;
}

--[[
	获取允许显示的文本内容local args = {textContent = '这是一个参数示例',textComponent = self.Text.chatTxt1,widthOriginal = 393,textTarget = '...'}
	textContent:原文本内容
	textComponent:text组件
    widthOriginal:text组件节点的width(通过直接传入这个值,来避免在此方法内频繁调用GetComponent)
    widthTarget:想要显示的区域宽度(比如省略号宽度10,那width就是10)和textTarget二选一传入
    textTarget:想要添加的字符串(比如添加省略号'...')和widthTarget二选一传入
    示例功能详见hud界面左下角的聊天栏
]]
function string.getShowText(args)
    local widthTarget = args.widthTarget
    if not args.widthTarget and args.textTarget then
        widthTarget = args.textComponent:GetFontWidth(args.textTarget)
    end
    local tempWidth = 0
    local stringTemp = ''
    local stringTarget = ''
    local tab = string.splitString(args.textContent)
    for i=1,#tab do
        stringTarget = stringTemp
        stringTemp = stringTemp .. tab[i]
        tempWidth = args.textComponent:GetFontWidth(stringTemp)
        if (widthTarget + tempWidth) >= args.widthOriginal then
            break
        end
    end
    if (widthTarget + tempWidth) >= args.widthOriginal then
        if args.textTarget then
            stringTarget = stringTarget .. args.textTarget
        end
    else
        stringTarget = stringTemp
    end
    return stringTarget
end

--[[
	拆分字符串
]]
function string.splitString(s) 
    local tab = {}
    local f = '[%z\1-\127\194-\244][\128-\191]*'
    for v in string.gmatch(s,f) do
        table.insert(tab , v)
    end
    return tab;
end

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