Android仿支付宝自定义密码输入框及安全键盘(密码键盘)

 0、前言

之前做过的项目里有运用到一个支付场景：用户办理业务时需要输入交易密码，并且可根据平台下发的支付方式进行选择。这与支付宝的密码输入方式十分相似，如果使用Android系统或者第三方软件的键盘，会有密码泄露的风险。因此，大多数的应用软件使用的是自定义的密码输入框及安全键盘。

由于密码输入方式需要实现一个从底部弹出的效果，因此总体上决定采用BottomSheetDialog来进行封装，同时为了提高安全性，还应该随机生成键盘上的数字，界面如下图所示：

首先新建一个PasswordInputView类，将需要使用到的Context对象、支付金额、可支持的支付方式等数据，作为该类构造方法的参数进行传递。下文还将提到该类有一个回调方法，当用户输入的密码满足六位时，可以在回调方法中获取密码并显示出来。PasswordInputView类的构造方法如下所示：

public PasswordInputView(Context context, String payMoney, List<String> payWayList) {
 this.context = context;
 this.payMoney = payMoney;
 this.payWayList = payWayList;
 payPwdDialog = new BottomSheetDialog(context);
 View view = LayoutInflater.from(context).inflate(R.layout.dialog_pay_pwd, null, false);
 initStep1(view);
 initStep2(view);
 llyPwdInputView = (LinearLayout) view.findViewById(R.id.lly_pwd_input_view);
 llyPayWaySelect = (LinearLayout) view.findViewById(R.id.lly_pay_way_select);
 showStep1(); // 显示第一页
} 

1、自定义密码输入框

因为不能明文显示输入的密码，所以使用“●”来代替每位密码。自定义密码输入框涉及到的自定义属性，主要包括：输入框的大小、颜色、圆角半径以及密码圆点的大小、颜色、半径。因此，自定义属性attrs.xml文件如下所示：

<?xml version="1.0" encoding="utf-8"?>
<resources>
 <declare-styleable name="PasswordEditText">
  <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>
</resources> 

接下来就需要去绘制自定义控件了。首先获取自定义属性，然后在onDraw()中进行绘制，代码如下所示：

package com.syd.paypwddialogdemo;
import static android.graphics.Paint.ANTI_ALIAS_FLAG;
import android.content.Context;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.support.v7.widget.AppCompatEditText;
import android.util.AttributeSet;
/**
 * 自定义密码输入框
 */
public class PasswordEditText extends AppCompatEditText {
 private int textLength;
 private int borderColor;
 private float borderWidth;
 private float borderRadius;
 private int passwordLength;
 private int passwordColor;
 private float passwordWidth;
 private float passwordRadius;
 private Paint passwordPaint = new Paint(ANTI_ALIAS_FLAG);
 private Paint borderPaint = new Paint(ANTI_ALIAS_FLAG);
 private final int defaultContMargin = 5;
 private final int defaultSplitLineWidth = 3;
 public PasswordEditText(Context context, AttributeSet attrs) {
  super(context, attrs);
  final Resources res = getResources();
  final int defaultBorderColor = res.getColor(R.color.colorGray);
  final float defaultBorderWidth = res.getDimension(R.dimen.default_ev_border_width);
  final float defaultBorderRadius = res.getDimension(R.dimen.default_ev_border_radius);
  final int defaultPasswordLength = res.getInteger(R.integer.default_ev_password_length);
  final int defaultPasswordColor = res.getColor(R.color.colorBlack);
  final float defaultPasswordWidth = res.getDimension(R.dimen.default_ev_password_width);
  final float defaultPasswordRadius = res.getDimension(R.dimen.default_ev_password_radius);
  TypedArray a = context.getTheme().obtainStyledAttributes(attrs, R.styleable.PasswordEditText, 0, 0);
  try {
   borderColor = a.getColor(R.styleable.PasswordEditText_borderColor, defaultBorderColor);
   borderWidth = a.getDimension(R.styleable.PasswordEditText_borderWidth, defaultBorderWidth);
   borderRadius = a.getDimension(R.styleable.PasswordEditText_borderRadius, defaultBorderRadius);
   passwordLength = a.getInt(R.styleable.PasswordEditText_passwordLength, defaultPasswordLength);
   passwordColor = a.getColor(R.styleable.PasswordEditText_passwordColor, defaultPasswordColor);
   passwordWidth = a.getDimension(R.styleable.PasswordEditText_passwordWidth, defaultPasswordWidth);
   passwordRadius = a.getDimension(R.styleable.PasswordEditText_passwordRadius, defaultPasswordRadius);
  } finally {
   a.recycle();
  }
  borderPaint.setStrokeWidth(borderWidth);
  borderPaint.setColor(borderColor);
  passwordPaint.setStrokeWidth(passwordWidth);
  passwordPaint.setStyle(Paint.Style.FILL);
  passwordPaint.setColor(passwordColor);
 }
 @Override
 protected void onDraw(Canvas canvas) {
  int width = getWidth();
  int height = getHeight();
  RectF rect = new RectF(0, 0, width, height);
  borderPaint.setColor(borderColor);
  canvas.drawRoundRect(rect, borderRadius, borderRadius, borderPaint);
  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);
  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);
  }
  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);
  }
 }
 @Override
 protected void onTextChanged(CharSequence text, int start, int lengthBefore, int lengthAfter) {
  super.onTextChanged(text, start, lengthBefore, lengthAfter);
  this.textLength = text.toString().length();
  invalidate();
 }
 public int getBorderColor() {
  return borderColor;
 }
 public void setBorderColor(int borderColor) {
  this.borderColor = borderColor;
  borderPaint.setColor(borderColor);
  invalidate();
 }
 public float getBorderWidth() {
  return borderWidth;
 }
 public void setBorderWidth(float borderWidth) {
  this.borderWidth = borderWidth;
  borderPaint.setStrokeWidth(borderWidth);
  invalidate();
 }
 public float getBorderRadius() {
  return borderRadius;
 }
 public void setBorderRadius(float borderRadius) {
  this.borderRadius = borderRadius;
  invalidate();
 }
 public int getPasswordLength() {
  return passwordLength;
 }
 public void setPasswordLength(int passwordLength) {
  this.passwordLength = passwordLength;
  invalidate();
 }
 public int getPasswordColor() {
  return passwordColor;
 }
 public void setPasswordColor(int passwordColor) {
  this.passwordColor = passwordColor;
  passwordPaint.setColor(passwordColor);
  invalidate();
 }
 public float getPasswordWidth() {
  return passwordWidth;
 }
 public void setPasswordWidth(float passwordWidth) {
  this.passwordWidth = passwordWidth;
  passwordPaint.setStrokeWidth(passwordWidth);
  invalidate();
 }
 public float getPasswordRadius() {
  return passwordRadius;
 }
 public void setPasswordRadius(float passwordRadius) {
  this.passwordRadius = passwordRadius;
  invalidate();
 }
} 

2、安全键盘的实现

安全键盘主要是通过GridView来实现，上文提到为了保证安全性，在安全键盘初始化的时候，应该随机生成键盘上的数字，代码如下所示：

/**
 * 初始化密码键盘
 */
private void initKeyboard() {
 final int number = 10;
 int[] keys = new int[number];
 for (int i = 0; i < 10; i++) {
  keys[i] = i;
 }
 // 随机生成键盘数字
 Random random = new Random();
 for (int i = 0; i < number; i++) {
  int p = random.nextInt(number);
  int tmp = keys[i];
  keys[i] = keys[p];
  keys[p] = tmp;
 }
 numList = new ArrayList<>();
 for (int i = 0; i < 12; i++) {
  Map<String, String> map = new HashMap<>();
  if (i < 9) {
   map.put("num", String.valueOf(keys[i]));
  } else if (i == 9) {
   map.put("num", "");
  } else if (i == 10) {
   map.put("num", String.valueOf(keys[9]));
  } else if (i == 11) {
   map.put("num", "");
  }
  numList.add(map);
 }
 KeyAdapter keyAdapter = new KeyAdapter(context, numList, handler);
 gvKeyboard.setAdapter(keyAdapter);
} 

安全键盘点击事件的处理，是在适配器KeyAdapter的构造方法中传入Handler对象，通过收发消息的方式在PasswordInputView类中处理的，代码如下所示：

holder.btnKey.setOnClickListener(new View.OnClickListener() {
 @Override
 public void onClick(View v) {
  Message msg = new Message();
  msg.what = Constants.KEYBOARD_INPUT;
  msg.obj = position;
  handler.sendMessage(msg);
 }
}); 

Handler对象在PasswordInputView类中定义，主要用于处理安全键盘的点击事件，代码如下所示：

Handler handler = new Handler() {
 @Override
 public void dispatchMessage(Message msg) {
  switch (msg.what) {
   case Constants.KEYBOARD_INPUT:
    int position = (int) msg.obj;
    if (position < 11 && position != 9) {
     // 点击0-9按键
     password = etPwd.getText().append(numList.get(position).get("num")).toString();
     etPwd.setText(password);
    } else {
     if (position == 11) {
      // 点击退格键
      if (!TextUtils.isEmpty(password) && !password.equals("")) {
       password = etPwd.getText().delete(password.length() - 1, password.length()).toString();
       etPwd.setText(password);
      }
     }
    }
    break;
  }
 }
}; 

为了方便外部获取到用户输入的密码，设计一个回调接口OnPwdInputListener，并在PasswordInputView类中为回调接口创建一个set方法，代码如下所示：

package com.syd.paypwddialogdemo;
public interface OnPwdInputListener {
 void onPwdInput(String password);
} 

当PasswordEditText控件的TextWatcher对象监听到输入的密码满足六位时，调用回调方法，将密码作为参数进行传递，代码如下所示：

textWatcher = new TextWatcher() {
 @Override
 public void afterTextChanged(Editable s) {
  if (etPwd.getText().length() == 6) {
   onPwdInputListener.onPwdInput(etPwd.getText().toString());
  }
 }
};
etPwd.addTextChangedListener(textWatcher); 

在外部调用set方法，创建OnPwdInputListener对象，重写回调方法，即可获取到用户输入的密码，代码如下所示：

pwdInputView.setOnPwdInputListener(new OnPwdInputListener() {
 @Override
 public void onPwdInput(String password) {
  Toast.makeText(MainActivity.this, password, Toast.LENGTH_SHORT).show();
 }
}); 

3、结语

以上介绍了自定义密码输入框及安全键盘的大致实现思路，对源码感兴趣的小伙伴可以点击下载Demo，查看具体的实现过程及演示效果。

您可能感兴趣的文章:

• android仿支付宝、微信密码输入框效果
• android仿微信支付宝的支付密码输入框示例
• Android 仿支付宝密码输入框效果
• Android仿支付宝支付密码输入框
• Android仿支付宝、京东的密码键盘和输入框
• Android仿微信/支付宝密码输入框