Android仿支付宝自定义密码输入框及安全键盘(密码键盘)

2019-10-22 18:15:52

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来源：转载

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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：

android,支付宝,密码输入框,自定义密码输入框,密码键盘

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();  } });