android 密码输入框

1.效果如下

306347510301723728.png

2.实现方式
继承EditText,绘制矩形边框，绘制内部5条线， 绘制中间圆点。
3.代码如下

public class MyEditTest extends AppCompatEditText {
    private static final String TAG = "MyEditTest";
    private int width;
    private int height;
    private int divideLineWStartX;
    private int firstCircleW;
    private int maxCount=6;
    private int inputLength;
    private Paint pLine;
    private Paint pCircle;
    private Context context;
    public MyEditTest(Context context) {
        this(context,null);
    }

    public MyEditTest(Context context, AttributeSet attrs) {
        super(context, attrs);
        this.context=context;
        this.setBackgroundColor(Color.TRANSPARENT);//========================>>1
        this.setCursorVisible(false);//========================================>>2
        initPaint();
    }

    private void initPaint(){
        pLine=new Paint();
        pLine.setColor(Color.parseColor("#666666"));
        pLine.setAntiAlias(true);
        pLine.setStyle(Paint.Style.STROKE);

        pCircle=new Paint();
        pCircle.setColor(Color.parseColor("#333333"));
        pCircle.setAntiAlias(true);
        pCircle.setStyle(Paint.Style.FILL);
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        height=h;
        width=w;
        //第一条竖线 x位置
        divideLineWStartX = w / maxCount;
        //第一个圆x 位置
        firstCircleW=divideLineWStartX/2;
    }

    @Override
    protected void onDraw(Canvas canvas) {
//        super.onDraw(canvas);=======================================>>3
        drawRect(canvas);
        drawLine(canvas);
        drawCircle(canvas);
    }

    private void drawLine(Canvas canvas) {
//        通过循环画出每个分割线
        for (int i = 0; i < maxCount - 1; i++) {
            canvas.drawLine((i + 1) * divideLineWStartX,
                    0,
                    (i + 1) * divideLineWStartX,
                    height,
                    pLine);
        }
    }

    private void drawCircle(Canvas canvas) {
        for (int i = 0; i < inputLength; i++) {
            canvas.drawCircle(firstCircleW + i * 2 * firstCircleW,
                    height/2,
                    dp2px(context,5),
                    pCircle);
        }
    }

    private void drawRect(Canvas canvas) {
        canvas.drawRoundRect(new RectF(0,0,width,height),dp2px(context,2),dp2px(context,2),pLine);
    }

    @Override
    protected void onTextChanged(CharSequence text, int start, int lengthBefore, int lengthAfter) {
        super.onTextChanged(text, start, lengthBefore, lengthAfter);
        inputLength=text.length();
        if (inputLength>=6){
            this.setEnabled(false);
            backData.onDataBack(text.toString());
        }
        invalidate();
    }


    public void setBackData(OnBackData backData) {
        this.backData = backData;
    }

    /**
     * 根据手机的分辨率从 dp 的单位 转成为 px(像素)
     */
    public static int dp2px(Context context, float dpValue) {
        final float scale = context.getResources().getDisplayMetrics().density;
        return (int) (dpValue * scale + 0.5f);
    }

    private OnBackData backData;
    public interface OnBackData{
        /**
         * 6位数字密码
         * @param pwd
         */
        void onDataBack(String pwd);
    }
}

4.绘制矩形边框、绘制内部5竖条线倒挺容易，在绘制圆点时，需要重写“onTextChanged”方法，在里面判断输入字符的长度，根据字符的长度，绘制圆点的个数。

    @Override
    protected void onTextChanged(CharSequence text, int start, int lengthBefore, int lengthAfter) {
        super.onTextChanged(text, start, lengthBefore, lengthAfter);
        inputLength=text.length();
        if (inputLength>=6){
            this.setEnabled(false);
            backData.onDataBack(text.toString());
        }
        invalidate();
    }

5.注意“1”处，去掉edittext自带的红色背景线，“2”处去掉不断闪烁的焦点指示图标，“3”处“ super.onDraw(canvas);”如果不注释掉，会绘制原本输入的字符。