详解Android的登录那点事

2019-12-12 04:16:42

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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。

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