Android之登录那点事

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。