随着互联网的高速发展，一个应用为了保护用户的隐私，通常会通过设置用户名+密码的验证方式保证用户隐私的相对安全，我知道一般网站的登录验证，通常会设置一个二维码，通过验证二维码，防止恶意软件通过机械程序，对用户密码进行破解，那么Android设备如何实现这个功能呢？相信很多开发者对此不屑一顾，因为这样增加了用户使用的复杂性，很多软件是不会这样设计的，现在我们暂且不谈它是不是有用，今天我们重点探讨一下，如何在Android的设备上实现这个功能。本篇为大家介绍的内容包括：1、用户连续多次输错密码，增加验证码验证；2、Android如何通过http请求达到与服务器之间的通讯。好了下面开始我们今天内容的介绍，首先我们先一起来学习一下如何实现用户连续多次输错密码，增加验证码功能。
既然用的到二维码，那么Android如何生成二维码呢？为大家提供一个生成二维码的类：
//生成二维码的类 public class BPUtil { /** * 用于生成二维码的字符 */ private static final char[] CHARS = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a','b','c','d','e','f','g','h','i','j','k','m','l','n','o','p','q','r','s','t','u','v','w','x','y','z', 'A','B','C','D','E','F','G','H','I','J','K','M','L','N','O','P','Q','R','S','T','U','V','W','X','Y','Z' }; private static BPUtil bpUtil; public static BPUtil getInstance() { if(bpUtil == null) bpUtil = new BPUtil(); return bpUtil; } // width="60" height="30" // base_padding_left="5" // range_padding_left="10" // base_padding_top="15" // range_padding_top="10" // codeLength="4" // line_number="3" // font_size="20" //default settings private static final int DEFAULT_CODE_LENGTH = 4; private static final int DEFAULT_FONT_SIZE = 20; private static final int DEFAULT_LINE_NUMBER = 3; private static final int BASE_PADDING_LEFT = 5, RANGE_PADDING_LEFT = 10, BASE_PADDING_TOP = 15, RANGE_PADDING_TOP = 10; private static final int DEFAULT_WIDTH = 60, DEFAULT_HEIGHT = 30; //settings decided by the layout xml //canvas width and height private int width = DEFAULT_WIDTH, height = DEFAULT_HEIGHT; //random word space and pading_top private int base_padding_left = BASE_PADDING_LEFT, range_padding_left = RANGE_PADDING_LEFT, base_padding_top = BASE_PADDING_TOP, range_padding_top = RANGE_PADDING_TOP; //number of chars, lines; font size private int codeLength = DEFAULT_CODE_LENGTH, line_number = DEFAULT_LINE_NUMBER, font_size = DEFAULT_FONT_SIZE; //variables private String code; private int padding_left, padding_top; private Random random = new Random(); public Bitmap createBitmap() { padding_left = 0; Bitmap bp = Bitmap.createBitmap(width, height, Config.ARGB_8888); Canvas c = new Canvas(bp); code = createCode(); c.drawColor(Color.WHITE); Paint paint = new Paint(); paint.setTextSize(font_size); for (int i = 0; i < code.length(); i++) { randomTextStyle(paint); randomPadding(); c.drawText(code.charAt(i) + "", padding_left, padding_top, paint); } for (int i = 0; i < line_number; i++) { drawLine(c, paint); } c.save( Canvas.ALL_SAVE_FLAG );//保存 c.restore();// return bp; } public String getCode() { return bpUtil.createCode(); } private String createCode() { StringBuilder buffer = new StringBuilder(); for (int i = 0; i < codeLength; i++) { buffer.append(CHARS[random.nextInt(CHARS.length)]); } return buffer.toString(); } private void drawLine(Canvas canvas, Paint paint) { int color = randomColor(); int startX = random.nextInt(width); int startY = random.nextInt(height); int stopX = random.nextInt(width); int stopY = random.nextInt(height); paint.setStrokeWidth(1); paint.setColor(color); canvas.drawLine(startX, startY, stopX, stopY, paint); } private int randomColor() { return randomColor(1); } private int randomColor(int rate) { int red = random.nextInt(256) / rate; int green = random.nextInt(256) / rate; int blue = random.nextInt(256) / rate; return Color.rgb(red, green, blue); } private void randomTextStyle(Paint paint) { int color = randomColor(); paint.setColor(color); paint.setFakeBoldText(random.nextBoolean()); //true为粗体，false为非粗体 float skewX = random.nextInt(11) / 10; skewX = random.nextBoolean() ? skewX : -skewX; paint.setTextSkewX(skewX); //float类型参数，负数表示右斜，整数左斜 // paint.setUnderlineText(true); //true为下划线，false为非下划 // paint.setStrikeThruText(true); //true为删除线，false为非删除 } private void randomPadding() { padding_left += base_padding_left + random.nextInt(range_padding_left); padding_top = base_padding_top + random.nextInt(range_padding_top); } }
有了二维码，下面我们开始设计我们的功能，这里先简单说一下，我们最终要实现的功能：1、用户正常输入用户名+密码登录；2、当用户连续3次输错密码，要求用户之后必须增加验证码输入验证。下面我们开始功能设计实现，首先是我们的布局文件：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="${relativePackage}.${activityClass}" android:orientation="vertical" > <LinearLayout android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal" android:text="@string/yanzheng" /> <LinearLayout android:orientation="horizontal" android:layout_width="fill_parent" android:layout_height="wrap_content" > <TextView android:layout_weight="1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/name" /> <EditText android:id="@+id/name" android:layout_width="wrap_content" android:layout_weight="6" android:layout_height="wrap_content" android:hint="@string/name_new" android:singleLine="true" /> </LinearLayout> <LinearLayout android:orientation="horizontal" android:layout_width="fill_parent" android:layout_height="wrap_content" > <TextView android:layout_weight="1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/password" /> <EditText android:id="@+id/pass" android:layout_weight="6" android:layout_width="wrap_content" android:layout_height="wrap_content" android:hint="@string/pass_new" android:singleLine="true" /> </LinearLayout> <LinearLayout android:id="@+id/layout_yanzhengma" android:visibility="gone" android:orientation="horizontal" android:layout_width="fill_parent" android:layout_height="wrap_content" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/yanzhengma" /> <TextView android:id="@+id/rander" android:layout_weight="1" android:layout_width="wrap_content" android:layout_height="wrap_content" /> <EditText android:id="@+id/rander_input" android:layout_weight="1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:singleLine="true" /> </LinearLayout> <LinearLayout android:orientation="horizontal" android:layout_width="fill_parent" android:layout_height="wrap_content" > <Button android:id="@+id/get" android:layout_weight="1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/get" /> <Button android:id="@+id/post" android:layout_weight="1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/post" /> </LinearLayout> </LinearLayout> </RelativeLayout>
重点的内容来了，我们主Activity代码，大家先看一下吧：
public class MainActivity extends Activity { private TextView mytext = null; private EditText myname = null;//用户名 private EditText mypass = null;//密码 private EditText myrander = null;//验证码 private Button mygetbutton = null;//Get方式发送Http请求 private Button mypostbutton = null;//Post方式发送Http请求 private LinearLayout myline = null;//控制二维码的显示 private static int n = 0;//用户输错密码次数统计 static String name = null;//用户输入的用户名 static String password = null;//用户输入的密码 private String edit;//用户输入用户输入的验证码 private String code;//验证码 @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); mytext = (TextView)findViewById(R.id.rander); myname = (EditText)findViewById(R.id.name); mypass = (EditText)findViewById(R.id.pass); myrander = (EditText)findViewById(R.id.rander_input); mygetbutton = (Button)findViewById(R.id.get); mypostbutton = (Button)findViewById(R.id.post); myline = (LinearLayout)findViewById(R.id.layout_yanzhengma); mygetbutton.setOnClickListener(new mygetbutton()); mypostbutton.setOnClickListener(new mypostbutton()); } class mygetbutton implements OnClickListener{ public void onClick(View v) { name = myname.getText().toString(); password = mypass.getText().toString(); if(n>=3){//连续三次输错密码 edit = myrander.getText().toString(); boolean boo = captcha (code , edit); if(boo){ new Thread(new Runnable() { public void run() { final boolean flag = SendServer.getsave(name, password); runOnUiThread(new Runnable() { public void run() { if(flag){ Toast.makeText(MainActivity.this, "登录成功", Toast.LENGTH_SHORT).show(); n=0; }else{ Toast.makeText(MainActivity.this, "登录失败", Toast.LENGTH_SHORT).show(); n++; if(n>=3){ myline.setVisibility(View.VISIBLE); } } } }); } }).start(); }else{ code = BPUtil.getInstance().getCode().toLowerCase();//生成新的二维码 mytext.setText(code);//展示在用户面前 } }else{ new Thread(new Runnable() { public void run() { final boolean flag = SendServer.getsave(name, password); runOnUiThread(new Runnable() { public void run() { if(flag){ Toast.makeText(MainActivity.this, "登录成功", Toast.LENGTH_SHORT).show(); n=0; }else{ Toast.makeText(MainActivity.this, "登录失败", Toast.LENGTH_SHORT).show(); n++; if(n>=3){ myline.setVisibility(1); code = BPUtil.getInstance().getCode().toLowerCase(); mytext.setText(code); } } } }); } }).start(); } } } class mypostbutton implements OnClickListener{ public void onClick(View v) { name = myname.getText().toString(); password = mypass.getText().toString(); new Thread(new Runnable() { public void run() { final boolean flag = SendServer.postsave(name, password); runOnUiThread(new Runnable() { @Override public void run() { if(flag){ Toast.makeText(MainActivity.this, "登录成功", Toast.LENGTH_SHORT).show(); n=0; }else{ Toast.makeText(MainActivity.this, "登录失败", Toast.LENGTH_SHORT).show(); n++; if(n>=3){ myline.setVisibility(1); } } } }); } }).start(); } } @SuppressLint("ShowToast") private boolean captcha (String code , String edit) { boolean flag = false; if (code.equals(edit)) { flag = true; }else { flag = false; Toast.makeText(MainActivity.this, " 验证码错误", 0).show(); // imageview.setImageBitmap(bitmap); } return flag; } protected void onRestart() { super.onRestart(); n=0; } protected void onDestroy() { super.onDestroy(); n=0; } }
在这里简单介绍一下代码，因为本篇接下来要为大家分享关于Android发送GET、POST请求的知识，这里我写了两个按钮，一个用来通过使用GET方式验证，一个通过使用POST方式验证，功能上是一致的。最后请大家注意一下：红色字体部分，红色字体部分就是我们通过调用上部二维码生成类，生成二维码，然后展示在用户界面。还有就是：onRestart、onDestroy都是Activity的生命周期函数，这里将n归零，方便我们的再次登录体验。好了到这里我们的第一部分就完成了，下面我们开始进入我们本篇的下半部分。
关于Android服务器请求，一般有两种方式：GET、POST两种方式，接下来我们就开始一起学习吧。
public class SendServer { //GET方式请求 public static boolean getsave(String name, String password) { boolean flag = false; HttpURLConnection conn = null; try { //防止中文乱码 String username = URLEncoder.encode(name, "UTF-8"); String userpassword = URLEncoder.encode(password, "UTF-8"); URL url = new URL("http://10.20.90.3:8080/Register/ManageServlet?"+"name="+username+"&password="+userpassword); conn = (HttpURLConnection) url.openConnection(); conn.setRequestMethod("GET"); conn.setConnectTimeout(5000); conn.setReadTimeout(5000); int responseCode = conn.getResponseCode(); if(responseCode == 200){ InputStream is = conn.getInputStream(); String stu = getStringFromInputStream(is); if(stu.equals("登录成功")){ flag = true; } } } catch (MalformedURLException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } finally{ if(conn != null){ conn.disconnect(); //关闭连接 } } return flag; } //POST请求 public static boolean postsave(String name, String password) { boolean flag = false; HttpURLConnection conn = null; try { URL url = new URL("http://10.20.90.3:8080/Register/ManageServlet?"); conn = (HttpURLConnection) url.openConnection(); conn.setRequestMethod("POST"); conn.setConnectTimeout(5000); conn.setReadTimeout(5000); //post请求参数 String data = "name="+name+"&password="+password; OutputStream out = conn.getOutputStream(); out.write(data.getBytes()); out.flush(); out.close(); // conn.setRequestProperty("Content-Length", 500);// 内容长度设置为500；请求头消息格式设置 int respon = conn.getResponseCode(); if(respon == 200){ InputStream is = conn.getInputStream(); String stu = getStringFromInputStream(is); if(stu.equals("登录成功")){ flag = true; } } } catch (Exception e) { e.printStackTrace(); }finally{ if(conn != null){ conn.disconnect(); } } return flag; } //解析服务返回的请求 private static String getStringFromInputStream(InputStream is) throws Exception{ ByteArrayOutputStream baos = new ByteArrayOutputStream(); byte[] buffer = new byte[1024*8]; int len = -1; while((len = is.read(buffer)) != -1){ baos.write(buffer, 0, len); } is.close(); String html = new String(baos.toByteArray(), "GBK");//接收服务器端的数据时，防止出现中文乱码。 //String html = baos.toString(); baos.close(); return html; } }
好了结束了，内容简单，大家自行了解吧。新手学习，高手交流。