Android 自定义密码输入框怎么实现

/**
   * 绘制背景外圆
   */
  private void drawOutRing(Canvas canvas) {
    mPaint.setColor(mBgColor);
    // 设置画笔为空心
    mPaint.setStyle(Paint.Style.STROKE);
    mPaint.setStrokeWidth(mBgSize);
    RectF rectF = new RectF(mBgSize, mBgSize, getWidth() - mBgSize, getHeight() - mBgSize);
    // 画圆
    for (int i = 0; i < mPasswordNumber; i++) {
      int cx = i * mDivisionLineSize + i * mPasswordItemWidth + mPasswordItemWidth / 2 + mBgSize;
      canvas.drawCircle(cx, getHeight() / 2, mOutRadius, mPaint);
    }
  }

/**
   * 绘制背景内圆
   */
  private void drawInRing(Canvas canvas) {
    mPaint.setColor(mDivisionLineColor);
    // 设置画笔为实心
    mPaint.setStyle(Paint.Style.FILL);
    // 画圈圈
    for (int i = 0; i < mPasswordNumber; i++) {
      int cx = i * mDivisionLineSize + i * mPasswordItemWidth + mPasswordItemWidth / 2 + mBgSize;
      canvas.drawCircle(cx, getHeight() / 2, mPasswordRadius, mPaint);
    }
  }
}

/**
   * 绘制隐藏的密码
   */
  private void drawHidePassword(Canvas canvas) {
    int passwordLength = getText().length();
    if (passwordLength > 6) passwordLength = 6;
    mPaint.setColor(mPasswordColor);
    // 画实心内圆
    mPaint.setStyle(Paint.Style.FILL);
    for (int i = 0; i < passwordLength; i++) {
      int cx = i * mDivisionLineSize + i * mPasswordItemWidth + mPasswordItemWidth / 2 + mBgSize;
      canvas.drawCircle(cx, getHeight() / 2, mPasswordRadius, mPaint);
    }
    //外圆颜色
    mPaint.setColor(mPasswordColor);
    // 设置画笔为空心
    mPaint.setStyle(Paint.Style.STROKE);
    mPaint.setStrokeWidth(mBgSize);
    RectF rectF = new RectF(mBgSize, mBgSize, getWidth() - mBgSize, getHeight() - mBgSize);
    // 画空心外圆
    for (int i = 0; i < passwordLength; i++) {
      int cx = i * mDivisionLineSize + i * mPasswordItemWidth + mPasswordItemWidth / 2 + mBgSize;
      canvas.drawCircle(cx, getHeight() / 2, mOutRadius, mPaint);
    }
  }

int passwordWidth = getWidth() - (mPasswordNumber - 1) * mDivisionLineSize;
    mPasswordItemWidth = passwordWidth / mPasswordNumber;
    // 绘制背景外圆
    drawOutRing(canvas);
    // 绘制背景内圆
    drawInRing(canvas);
    // 绘制密码
    drawHidePassword(canvas);

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.view.inputmethod.EditorInfo;
import android.widget.EditText;
/**
 *自定义密码输入框
 */
public class PasswordView extends EditText {
  // 画笔
  private Paint mPaint;
  // 一个密码所占的宽度
  private int mPasswordItemWidth;
  // 密码的个数默认为6位数
  private int mPasswordNumber = 6;
  // 背景圆颜色
  private int mBgColor = Color.parseColor("#d1d2d6");
  // 背景大小
  private int mBgSize = 1;
  // 背景边框圆角大小
  private int mBgCorner = 0;
  // 外圆的颜色
  private int outRingLineColor = mBgColor;
  // 外圆线条的大小
  private int outRingLineSize = 1;
  // 密码输入的颜色
  private int mPasswordColor = Color.parseColor("#cb3435");
   // 密码圆点的半径大小
  private int mPasswordRadius = 6;
  // 外圆半径大小
  private int mOutRadius = 25;
  public PasswordView(Context context) {
    this(context, null);
  }
  public PasswordView(Context context, AttributeSet attrs) {
    super(context, attrs);
    initPaint();
    initAttributeSet(context, attrs);
    // 设置输入模式是密码
    setInputType(EditorInfo.TYPE_TEXT_VARIATION_PASSWORD);
    // 不显示光标
    setCursorVisible(false);
  }
  /**
   * 初始化属性
   */
  private void initAttributeSet(Context context, AttributeSet attrs) {
    TypedArray array = context.obtainStyledAttributes(attrs, R.styleable.PasswordView);
    // 获取大小
    outRingLineSize = (int) array.getDimension(R.styleable.PasswordView_outRingLineSize, dip2px(outRingLineSize));
    mPasswordRadius = (int) array.getDimension(R.styleable.PasswordView_passwordRadius, dip2px(mPasswordRadius));
    mBgSize = (int) array.getDimension(R.styleable.PasswordView_bgSize, dip2px(mBgSize));
    mBgCorner = (int) array.getDimension(R.styleable.PasswordView_bgCorner, 0);
    // 获取颜色
    mBgColor = array.getColor(R.styleable.PasswordView_bgColor, mBgColor);
    outRingLineColor = array.getColor(R.styleable.PasswordView_outRingColor, outRingLineColor);
    mPasswordColor = array.getColor(R.styleable.PasswordView_passwordColor, mPasswordColor);
    array.recycle();
  }
  /**
   * 初始化画笔
   */
  private void initPaint() {
    mPaint = new Paint();
    mPaint.setAntiAlias(true);
    mPaint.setDither(true);
  }
  /**
   * dip 转 px
   */
  private int dip2px(int dip) {
    return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,
        dip, getResources().getDisplayMetrics());
  }
  @Override
  protected void onDraw(Canvas canvas) {
    int passwordWidth = getWidth() - (mPasswordNumber - 1) * outRingLineSize;
    mPasswordItemWidth = passwordWidth / mPasswordNumber;
    // 绘制背景外圆
    drawOutRing(canvas);
    // 绘制背景内圆
    drawInRing(canvas);
    // 绘制密码
    drawHidePassword(canvas);
  }
  @Override
  public void setText(CharSequence text, BufferType type) {
    super.setText(text, type);
  }
  /**
   * 绘制背景外圆
   */
  private void drawOutRing(Canvas canvas) {
    mPaint.setColor(mBgColor);
    // 设置画笔为空心
    mPaint.setStyle(Paint.Style.STROKE);
    mPaint.setStrokeWidth(mBgSize);
    RectF rectF = new RectF(mBgSize, mBgSize, getWidth() - mBgSize, getHeight() - mBgSize);
    // 画圆
    for (int i = 0; i < mPasswordNumber; i++) {
      int cx = i * outRingLineSize + i * mPasswordItemWidth + mPasswordItemWidth / 2 + mBgSize;
      canvas.drawCircle(cx, getHeight() / 2, mOutRadius, mPaint);
    }
  }
  /**
   * 绘制隐藏的密码
   */
  private void drawHidePassword(Canvas canvas) {
    int passwordLength = getText().length();
    if (passwordLength > 6) passwordLength = 6;
    mPaint.setColor(mPasswordColor);
    // 设置画笔为实心
    mPaint.setStyle(Paint.Style.FILL);
    for (int i = 0; i < passwordLength; i++) {
      int cx = i * outRingLineSize + i * mPasswordItemWidth + mPasswordItemWidth / 2 + mBgSize;
      canvas.drawCircle(cx, getHeight() / 2, mPasswordRadius, mPaint);
    }
    //外圆
    mPaint.setColor(mPasswordColor);
    // 设置画笔为空心
    mPaint.setStyle(Paint.Style.STROKE);
    mPaint.setStrokeWidth(mBgSize);
    RectF rectF = new RectF(mBgSize, mBgSize, getWidth() - mBgSize, getHeight() - mBgSize);
    // 如果没有设置圆角，就画矩形
    for (int i = 0; i < passwordLength; i++) {
      int cx = i * outRingLineSize + i * mPasswordItemWidth + mPasswordItemWidth / 2 + mBgSize;
      canvas.drawCircle(cx, getHeight() / 2, mOutRadius, mPaint);
    }
  }
  /**
   * 绘制背景内圆
   */
  private void drawInRing(Canvas canvas) {
    mPaint.setColor(outRingLineColor);
    // 设置画笔为实心
    mPaint.setStyle(Paint.Style.FILL);
    // 画圈圈
    for (int i = 0; i < mPasswordNumber; i++) {
      int cx = i * outRingLineSize + i * mPasswordItemWidth + mPasswordItemWidth / 2 + mBgSize;
      canvas.drawCircle(cx, getHeight() / 2, mPasswordRadius, mPaint);
    }
  }
}