TextView 一行文本，多的文字最后带省略符号

参考文章

Android之自定义TextView学习笔记
Android Canvas的drawText()和文字居中方案

该控件解决了什么问题

TextView只显示一行，后台提供10个文字，但是你只想显示5个，剩余的部分用...来表示

可以自定义哪些？

1、文本大小
2、文字颜色
3、文字信息

使用

  textViewSingleLineEllipsis0.setStringText("我要显示有100个文字，但是我只显示10个文字,德玛西亚,德玛西亚,德玛西亚,德玛西亚,德玛西亚,德玛西亚,德玛西亚,德玛西亚,德玛西亚,德玛西亚,德玛西亚,德玛西亚,德玛西亚,德玛西亚,德玛西亚,德玛西亚,德玛西亚,德玛西亚");
        textViewSingleLineEllipsis0.setMaxShowLength(10);
        textViewSingleLineEllipsis0.update();

 <com.gxx.widgetlibrary.textview.TextViewSingleLineEllipsis
        android:id="@+id/text_show_textview_single_ellipis_0"
        android:layout_width="wrap_content"
        app:text_ellipsis_length="10"
        app:text_ellipsis_textsize="@dimen/sp_18"
        app:text_ellipsis_color="@color/app_theme_color_sysm"
        android:layout_height="wrap_content"/>

attributes

  <declare-styleable name="TextViewSingleLineEllipsis">
       <attr name="text_ellipsis_textvalue" format="string"/>
        <attr name="text_ellipsis_length" format="integer"/>
        <attr name="text_ellipsis_color" format="color"/>
        <attr name="text_ellipsis_textsize" format="dimension"/>
    </declare-styleable>

代码

public class TextViewSingleLineEllipsis extends View {
     private int textColor = 0;
    private float textSize = 0;
    private int maxShowLength = 5;
    private String stringText = "";
    private Paint mPaint = new Paint();

    public TextViewSingleLineEllipsis(Context context) {
        this(context, null);
    }

    public TextViewSingleLineEllipsis(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public TextViewSingleLineEllipsis(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.TextViewSingleLineEllipsis);
        maxShowLength = typedArray.getInt(R.styleable.TextViewSingleLineEllipsis_text_ellipsis_length, 5);
        textSize = typedArray.getDimension(R.styleable.TextViewSingleLineEllipsis_text_ellipsis_textsize, getResources().getDimension(R.dimen.sp_14));
        textColor = typedArray.getColor(R.styleable.TextViewSingleLineEllipsis_text_ellipsis_color, getResources().getColor(R.color.black));
        stringText = typedArray.getString(R.styleable.TextViewSingleLineEllipsis_text_ellipsis_textvalue);
        typedArray.recycle();
        mPaint.setColor(textColor);
        mPaint.setTextSize(textSize);
        mPaint.setAntiAlias(true);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int width = 0, height = 0;
        int speceWithMode = MeasureSpec.getMode(widthMeasureSpec);
        int specWidthSize = MeasureSpec.getSize(widthMeasureSpec);
        switch (speceWithMode) {
            case MeasureSpec.EXACTLY:
                width = getPaddingLeft() + getPaddingRight() + specWidthSize;
                break;
            case MeasureSpec.AT_MOST:
            case MeasureSpec.UNSPECIFIED:
                float textWidth = mPaint.measureText(stringText);
                width = (int) (getPaddingLeft() + getPaddingRight() + textWidth);
                break;
        }

        int speceHeightMode = MeasureSpec.getMode(heightMeasureSpec);
        int specHeightSize = MeasureSpec.getSize(heightMeasureSpec);

        switch (speceHeightMode) {
            case MeasureSpec.EXACTLY:
                height = getPaddingTop() + getPaddingBottom() + specHeightSize;
                break;
            case MeasureSpec.AT_MOST:
            case MeasureSpec.UNSPECIFIED:
                Paint.FontMetrics fontMetrics = mPaint.getFontMetrics();
                float textHeight = Math.abs((fontMetrics.bottom - fontMetrics.top));
                height = (int) (getPaddingTop() + getPaddingBottom() + textHeight);
                break;
        }
        setMeasuredDimension(width, height);
    }


    @Override
    protected void onDraw(Canvas canvas) {
        if (!StringUtils.isEmpty(stringText)) {
            if (stringText.length() > maxShowLength) {
                stringText = stringText.substring(0, maxShowLength) + "...";
            }
            mPaint.setColor(textColor);
            mPaint.setTextSize(textSize);
            Paint.FontMetrics fontMetrics = mPaint.getFontMetrics();
            float distance = (fontMetrics.bottom - fontMetrics.top) / 2 - fontMetrics.bottom;
            canvas.drawText(stringText, 0, getHeight() / 2 + distance, mPaint);
        }
    }

    public void setStringText(String stringText) {
        if (!StringUtils.isEmpty(stringText)) {
            if (stringText.length() > maxShowLength) {
                this.stringText = stringText.substring(0, maxShowLength) + "...";
            }
        }
    }

    public void setTextColor(int color) {
        this.textColor = color;
    }

    public void setMaxShowLength(int maxShowLength) {
        this.maxShowLength = maxShowLength;
    }

    public void  setTextSize(float textSize){
        this.textSize = textSize;
    }


    public void update(){
        requestLayout();
        invalidate();
    }

    public String getStringText() {
        return stringText;
    }
}