一个可控长度,带下划线的自定义Edittext

看到带下划线的Edittext,估计大家会嗤之以鼻,Edittext本就自带下划线,但我要实现的是下划线是有间隔的。我们先看看效果,如果觉得有值得学习的地方再往下看,省得浪费时间。


一个可控长度,带下划线的自定义Edittext_第1张图片
下划线EdittextView.jpg

相信各位看官看了效果,应该不会觉得那么简单了吧,但其实也不难。我们可以通过继承Edittext自定义View来实现。为啥非得继承Edittext呢?原因很简单,系统提供的Edittext可以获取键盘的输入,省去了我们不少麻烦事。开始我也是想通过继承View来实现的,显得更高大上,有逼可装。但在适配过程中发现,国内有的手机厂商的手机我们是监听不到用户键盘点击事件的,除了删除等一些公用的(估计是为了用户信息安全考虑),因此也就放弃了这种实现方式。啰嗦了半天,现在我们正式进入正题(下面是实现核心代码):

private void init(AttributeSet attrs) {
    density = getContext().getResources().getDisplayMetrics().density;
    initDefaultAttributes();
    initCustomAttributes(attrs);
    initDataStructures();
    initPaint();
}

private void initDataStructures() {
    underlines = new Underline[underlineAmount];
}

private void initPaint() {
    underlinePaint = new Paint();
    underlinePaint.setColor(underlineColor);
    underlinePaint.setStrokeWidth(underlineStrokeWidth);
    underlinePaint.setStyle(Paint.Style.STROKE);
    textPaint = new Paint();
    textPaint.setTextSize(textSize);
    textPaint.setColor(textColor);
    textPaint.setAntiAlias(true);
    textPaint.setTextAlign(Paint.Align.CENTER);
    backgroundPaint = new Paint();
    backgroundPaint.setColor(backgroundColor);
}

@Override
protected void onSelectionChanged(int selStart, int selEnd) {
    super.onSelectionChanged(selStart, selEnd);
    if (selStart == selEnd){
        //使光标一直处于文末
        setSelection(getText().length());
    }
}

//设置下划线数量
public void setCodes(int codes) {
    underlineAmount = codes;
    initDataStructures();
}

private void initCustomAttributes(AttributeSet attrs) {
    TypedArray attributes = getContext().obtainStyledAttributes(attrs, R.styleable.EditTextView);
    try {
        underlineColor = attributes.getColor(R.styleable.EditTextView_underline_color, underlineColor);
        underlineAmount = attributes.getInt(R.styleable.EditTextView_codes, underlineAmount);
        textColor = attributes.getInt(R.styleable.EditTextView_text_color, textColor);
        textSize = attributes.getDimension(R.styleable.EditTextView_text_size, textSize);
        backgroundColor = attributes.getColor(R.styleable.EditTextView_background_color, backgroundColor);
    } finally {
        attributes.recycle();
    }
}

private void initDefaultAttributes() {
    underlineStrokeWidth = 2 * density;
    underlineWidth = 35 * density;
    underlineReduction = 5 * density;
    textSize = 15 * density;
    textMarginBottom = 15 * density;
    underlineColor = Color.parseColor("#cccccc");
    textColor = Color.parseColor("#000000");
    viewHeight = 50 * density;
    underlineAmount = DEFAULT_CODES;
    backgroundColor = Color.parseColor("#ffffff");
}

@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    super.onSizeChanged((int) ((underlineWidth + underlineReduction) * underlineAmount - underlineReduction), (int) viewHeight, oldw, oldh);
    height = h;
    width = w;
    initRect();
    initUnderline();
}

private void initRect() {
    rectBackground = new RectF(0, 0, width, height);
}


@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    setMeasuredDimension((int) ((underlineWidth + underlineReduction) * underlineAmount - underlineReduction), (int) viewHeight);
}

private void initUnderline() {
    for (int i = 0; i < underlineAmount; i++) {
        underlines[i] = createPath(i, underlineWidth);
    }
}

private Underline createPath(int position, float sectionWidth) {
    float fromX = (sectionWidth + underlineReduction) * (float) position;
    return new Underline(fromX, height, fromX + sectionWidth, height);
}

@Override
protected void onDraw(Canvas canvas) {
    //绘制白色背景将原有edittext遮住
    canvas.drawRect(rectBackground, backgroundPaint);
    for (int i = 0; i < underlines.length; i++) {
        Underline sectionpath = underlines[i];
        float fromX = sectionpath.getFromX();
        float fromY = sectionpath.getFromY();
        float toX = sectionpath.getToX();
        float toY = sectionpath.getToY();
        drawSection(fromX, fromY, toX, toY, canvas);
    }
    for (int i = 0; i < textLength; i++) {
        drawCharacter(underlines[i].getFromX(), underlines[i].getToX(), getText().toString().charAt(i), canvas);
    }
}

//绘制下划线
private void drawSection(float fromX, float fromY, float toX, float toY, Canvas canvas) {
    Paint paint = underlinePaint;
    canvas.drawLine(fromX, fromY, toX, toY, paint);
}

//绘制文字
private void drawCharacter(float fromX, float toX, Character character, Canvas canvas) {
    float actualWidth = toX - fromX;
    float centerWidth = actualWidth / 2;
    float centerX = fromX + centerWidth;
    canvas.drawText(String.valueOf(character), centerX, height - textMarginBottom, textPaint);
}

@Override
protected void onTextChanged(CharSequence text, int start, int lengthBefore, int lengthAfter) {
    super.onTextChanged(text, start, lengthBefore, lengthAfter);
    this.textLength = text.toString().length();
    Editable text1 = getText();
    if (text1.length() > underlineAmount){
        setText(text1.subSequence(0, underlineAmount));
        this.textLength = underlineAmount;
    }
}
    /**
     * 下划线
     */
    class Underline {

        float fromX;
        float fromY;
        float toX;
        float toY;

        public Underline() {
        }

        public Underline(float fromX, float fromY, float toX, float toY) {
            this.fromX = fromX;
            this.fromY = fromY;
            this.toX = toX;
            this.toY = toY;
        }

        public void from(float x, float y) {
            this.fromX = x;
            this.fromY = y;
        }

        public void to(float x, float y) {
            this.toX = x;
            this.toY = y;
        }

        public float getFromX() {
            return fromX;
        }

        public void setFromX(float fromX) {
            this.fromX = fromX;
        }

        public float getFromY() {
            return fromY;
        }

        public void setFromY(float fromY) {
            this.fromY = fromY;
        }

        public float getToX() {
            return toX;
        }

        public void setToX(float toX) {
            this.toX = toX;
        }

        public float getToY() {
            return toY;
        }

        public void setToY(float toY) {
            this.toY = toY;
        }
    }

    
    
    
    
    
    
    
    
    
    

没错就是这么简单,一个能够控制输入数量、下划线颜色可设置且携带所有Edittext属性的自定义View就这么实现了。若要查看源码可访问我的仓库。欢迎Star、Fork或者有更好的实现方式的建议可在下面留言,谢谢。

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