遵从准则

暴露您view中所有影响可见外观的属性或者行为。

• 通过XML添加和设置样式
• 通过元素的属性来控制其外观和行为，支持和重要事件交流的事件监听器

详细步骤见：Android 自定义View步骤

样子

支持的样式

可以通过XML定义影响外边和行为的属性如下

边框圆角值，边框颜色，分割线颜色，边框宽度，密码长度，密码大小，密码颜色

<declare-styleable name="PasswordInputView">
    <attr name="borderWidth" format="dimension"/>
    <attr name="borderColor" format="color"/>
    <attr name="borderRadius" format="dimension"/>
    <attr name="passwordLength" format="integer"/>
    <attr name="passwordWidth" format="dimension"/>
    <attr name="passwordColor" format="color"/>
    <attr name="passwordRadius" format="dimension"/>
</declare-styleable>

同时支持原来EditText功能，可以获得数据值，数字键盘设置等

绘制逻辑的主要代码

protected void onDraw(Canvas canvas) {
    int width = getWidth();
    int height = getHeight();

    // 外边框
    RectF rect = new RectF(0, 0, width, height);
    borderPaint.setColor(borderColor);
    canvas.drawRoundRect(rect, borderRadius, borderRadius, borderPaint);

    // 内容区
    RectF rectIn = new RectF(rect.left + defaultContMargin, rect.top + defaultContMargin,
            rect.right - defaultContMargin, rect.bottom - defaultContMargin);
    borderPaint.setColor(Color.WHITE);
    canvas.drawRoundRect(rectIn, borderRadius, borderRadius, borderPaint);

    // 分割线
    borderPaint.setColor(borderColor);
    borderPaint.setStrokeWidth(defaultSplitLineWidth);
    for (int i = 1; i < passwordLength; i++) {
        float x = width * i / passwordLength;
        canvas.drawLine(x, 0, x, height, borderPaint);
    }

    // 密码
    float cx, cy = height/ 2;
    float half = width / passwordLength / 2;
    for(int i = 0; i < textLength; i++) {
        cx = width * i / passwordLength + half;
        canvas.drawCircle(cx, cy, passwordWidth, passwordPaint);
    }
}   

完整代码下载

https://github.com/tianshaojie/Android-PasswordInputView