Php 数据库正在更新，但没有显示警报消息，登录也不起作用，它会停止-Android Studio

当我单击“注册数据库正在更新但警报框不工作”，并希望用toast消息替换警报框时。另外，当我尝试登录应用程序失败时，会报告“不幸的是，您的应用程序已停止”。我在这里呆了一个多星期，有人能给出解决方案吗

后台任务.java

public class BackgroundTask extends AsyncTask<String,Void,String>{
String register_url="http://bloodlk.16mb.com/register.php";
String login_url="bloodlk.16mb.com/login.php";
Context ctx;
Activity activity;
AlertDialog.Builder builder;
ProgressDialog progressDialog;

public BackgroundTask(Context ctx)
{
    this.ctx = ctx;
    activity=(Activity)ctx;
}
@Override
protected void onPreExecute() {
 builder = new AlertDialog.Builder(activity);
    progressDialog = new ProgressDialog(ctx);
    progressDialog.setTitle("Please Wait");
    progressDialog.setMessage("Connecting to Server...");
    progressDialog.setIndeterminate(true);
    progressDialog.setCancelable(false);
    progressDialog.show();
}

@Override
protected String doInBackground(String... params) {
    String method = params[0];

    if (method.equals("register"))
    {
        try {
            URL url = new URL(register_url);
            HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection();
            httpURLConnection.setRequestMethod("POST");
            httpURLConnection.setDoOutput(true);
            httpURLConnection.setDoInput(true);
            OutputStream outputStream = httpURLConnection.getOutputStream();
            BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream,"UTF-8"));
            String username = params[1];
            String email = params[2];
            String password = params[3];


            String data = URLEncoder.encode("name","UTF-8")+"="+URLEncoder.encode(username,"UTF-8")+"&"+
                    URLEncoder.encode("email","UTF-8")+"="+URLEncoder.encode(email,"UTF-8")+"&"+
                    URLEncoder.encode("password","UTF-8")+"="+URLEncoder.encode(password,"UTF-8");

            bufferedWriter.write(data);
            bufferedWriter.flush();
            bufferedWriter.close();
            outputStream.close();

            InputStream inputStream = httpURLConnection.getInputStream();
            BufferedReader bufferedReader =new BufferedReader(new InputStreamReader(inputStream));
            StringBuilder stringBuilder= new StringBuilder();
            String line = "";
            while ((line = bufferedReader.readLine())!=null);
            {
                stringBuilder.append(line+"\n");
            }
            httpURLConnection.disconnect();
            Thread.sleep(5000);
            return stringBuilder.toString().trim();
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
    else if (method.equals("login"))
    {
        try {
            URL url = new URL(login_url);
            HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection();
            httpURLConnection.setRequestMethod("POST");
            httpURLConnection.setDoOutput(true);
            httpURLConnection.setDoInput(true);
            OutputStream outputStream = httpURLConnection.getOutputStream();
            BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream,"UTF-8"));

            String email = params[1];
            String password = params[2];

            String data = URLEncoder.encode("email","UTF-8")+"="+URLEncoder.encode(email,"UTF-8")+"&"+
                    URLEncoder.encode("password","UTF-8")+"="+URLEncoder.encode(password,"UTF-8");
            bufferedWriter.write(data);
            bufferedWriter.flush();
            bufferedWriter.close();
            outputStream.close();

            InputStream inputStream = httpURLConnection.getInputStream();
            BufferedReader bufferedReader =new BufferedReader(new InputStreamReader(inputStream));
            StringBuilder stringBuilder= new StringBuilder();
            String line = "";
            while ((line = bufferedReader.readLine())!=null);
            {
                stringBuilder.append(line+"\n");
            }
            httpURLConnection.disconnect();
            Thread.sleep(5000);
            return stringBuilder.toString().trim();

        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (ProtocolException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
    return null;
}

@Override
protected void onProgressUpdate(Void... values) {
    super.onProgressUpdate(values);
}

@Override
protected void onPostExecute(String json) {
    try {
        progressDialog.dismiss();
        JSONObject jsonObject = new JSONObject(json);
        JSONArray jsonArray = jsonObject.getJSONArray("server_response");
        JSONObject JO = jsonArray.getJSONObject(0);
        String code = JO.getString("code");
        String message = JO.getString("message");
        if (code.equals("reg_true"))
        {

            showDialog("Registration Success !", message, code);
        }
        else if(code.equals("reg_false"))
        {
            showDialog("Registration Failed !",message,code);
        }
        else if (code.equals("login_true"))
        {
            Intent intent = new Intent(activity,profile.class);
            intent.putExtra("message",message);
            activity.startActivity(intent);
        }

        else if (code.equals("login_false"))
        {
            showDialog("Login Failed",message,code);
        }
        AlertDialog alertDialog= builder.create();
        alertDialog.show();

    } catch (JSONException e) {
        e.printStackTrace();
    }

}
public void showDialog(String title,String message,String code)
{
    builder.setTitle(title);
    if (code.equals("reg_true")|| code.equals("reg_false"))
    {
        builder.setMessage(message);
        builder.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                dialog.dismiss();
                activity.finish();
            }
        });
    }
    else if (code.equals("login_false"))
    {
        builder.setMessage(message);
        builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                EditText email, password;
                email = (EditText) activity.findViewById(R.id.edEmaillogin);
                password = (EditText) activity.findViewById(R.id.edPasslogin);
                email.setText("");
                password.setText("");
                dialog.dismiss();
            }
        });
        AlertDialog alertDialog= builder.create();
        alertDialog.show();
    }
}
}

公共类BackgroundTask扩展了AsyncTask{
字符串寄存器\u url=”http://bloodlk.16mb.com/register.php";
String login_url=“bloodlk.16mb.com/login.php”；
上下文ctx；
活动；
AlertDialog.Builder；
进行对话进行对话；
公共背景任务（上下文ctx）
{
this.ctx=ctx；
活动=（活动）ctx；
}
@凌驾
受保护的void onPreExecute（）{
builder=新建AlertDialog.builder（活动）；
progressDialog=新的progressDialog（ctx）；
progressDialog.setTitle（“请稍候”）；
设置消息（“连接到服务器…”）；
progressDialog.setUndeterminate（true）；
progressDialog.setCancelable（假）；
progressDialog.show（）；
}
@凌驾
受保护的字符串doInBackground（字符串…参数）{
字符串方法=参数[0]；
if（方法等于（“寄存器”））
{
试一试{
URL=新URL（注册URL）；
HttpURLConnection HttpURLConnection=（HttpURLConnection）url.openConnection（）；
httpURLConnection.setRequestMethod（“POST”）；
httpURLConnection.setDoOutput（true）；
httpURLConnection.setDoInput（true）；
OutputStream OutputStream=httpURLConnection.getOutputStream（）；
BufferedWriter BufferedWriter=新的BufferedWriter（新的OutputStreamWriter（outputStream，UTF-8））；
字符串username=params[1]；
字符串email=params[2]；
字符串密码=参数[3]；
字符串数据=URLEncoder.encode（“名称”，“UTF-8”）+”=“+URLEncoder.encode（用户名，“UTF-8”）+”&”+
URLEncoder.encode（“电子邮件”，“UTF-8”）+”=“+URLEncoder.encode（电子邮件，“UTF-8”）+”&”+
urlcoder.encode（“密码”，“UTF-8”）+“=”+urlcoder.encode（密码，“UTF-8”）；
bufferedWriter.write（数据）；
bufferedWriter.flush（）；
bufferedWriter.close（）；
outputStream.close（）；
InputStream InputStream=httpURLConnection.getInputStream（）；
BufferedReader BufferedReader=新的BufferedReader（新的InputStreamReader（inputStream））；
StringBuilder StringBuilder=新的StringBuilder（）；
字符串行=”；
而（（line=bufferedReader.readLine（））！=null）；
{
stringBuilder.append（行+“\n”）；
}
httpURLConnection.disconnect（）；
睡眠（5000）；
返回stringBuilder.toString（）.trim（）；
}捕获（格式错误）{
e、 printStackTrace（）；
}捕获（IOE异常）{
e、 printStackTrace（）；
}捕捉（中断异常e）{
e、 printStackTrace（）；
}
}
else if（method.equals（“login”））
{
试一试{
URL=新URL（登录\ URL）；
HttpURLConnection HttpURLConnection=（HttpURLConnection）url.openConnection（）；
httpURLConnection.setRequestMethod（“POST”）；
httpURLConnection.setDoOutput（true）；
httpURLConnection.setDoInput（true）；
OutputStream OutputStream=httpURLConnection.getOutputStream（）；
BufferedWriter BufferedWriter=新的BufferedWriter（新的OutputStreamWriter（outputStream，UTF-8））；
字符串email=params[1]；
字符串密码=参数[2]；
字符串数据=urlcoder.encode（“电子邮件”，“UTF-8”）+”=“+urlcoder.encode（电子邮件，“UTF-8”）+”&”+
urlcoder.encode（“密码”，“UTF-8”）+“=”+urlcoder.encode（密码，“UTF-8”）；
bufferedWriter.write（数据）；
bufferedWriter.flush（）；
bufferedWriter.close（）；
outputStream.close（）；
InputStream InputStream=httpURLConnection.getInputStream（）；
BufferedReader BufferedReader=新的BufferedReader（新的InputStreamReader（inputStream））；
StringBuilder StringBuilder=新的StringBuilder（）；
字符串行=”；
而（（line=bufferedReader.readLine（））！=null）；
{
stringBuilder.append（行+“\n”）；
}
httpURLConnection.disconnect（）；
睡眠（5000）；
返回stringBuilder.toString（）.trim（）；
}捕获（格式错误）{
e、 printStackTrace（）；
}捕获（协议例外e）{
e、 printStackTrace（）；
}捕获（不支持的编码异常e）{
e、 printStackTrace（）；
}捕获（IOE异常）{
e、 printStackTrace（）；
}捕捉（中断异常e）{
e、 printStackTrace（）；
}
}
返回null；
}
@凌驾
受保护的void onProgressUpdate（void…值）{
super.onProgressUpdate（值）；
}
@凌驾
受保护的void onPostExecute（字符串json）{
试一试{
progressDialog.disclose（）；
JSONObject JSONObject=新的JSONObject（json）；
JSONArray JSONArray=jsonObject.getJSONArray（“服务器响应”）；
JSONObject JO=jsonArray.getJSONObject（0）；
字符串代码=JO.getString（“代码”）；
字符串消息=JO.getString（“消息”）；
if（代码等于（“reg_true”））
{
showDialog（“注册成功！”，消息，代码）；
}
else if（代码等于（“reg_false”））
{
showDialog（“注册失败！”，消息，代码）；
}
else if（code.equals（“login_true”））
{
意向意向=新意向（活动、概要文件、类）；
intent.putExtra（“消息”，消息）；
活动。开始触觉（意图）；
}
else if（code.equals（“login_false”））
{
showDia
<?php

$name = $_POST["name"];
$email = $_POST["email"];
$pass = $_POST["password"];
require "init.php";

$query = "select * from userinfo where email like '".$email."';";
$result = mysqli_query($con,$query);

if(mysqli_num_rows($result)>0)
{

$response = array();
$code = "reg_false";
$message = "User Already Exist !";
array_push($response,array("code"=>$code,"message"=>$message));
echo json_encode(array("server_response"=>$response));

}
else
{
$query = "insert into userinfo     values('".$name."','".$email."','".$pass."');";
$result = mysqli_query($con,$query);

if(!$result)
{
    $response = array();
    $code = "reg_false";
    $message = "Registration Failed, Try Again!";
    array_push($response,array("code"=>$code,"message"=>$message));
    echo json_encode(array("server_response"=>$response));
}
else
{
    $response = array();
    $code = "reg_true";
    $message = "Registration Success, Login to Continue!";
    array_push($response,array("code"=>$code,"message"=>$message));
    echo json_encode(array("server_response"=>$response));
}   
}
mysqli_close($con);
?>

<?php
$email = $_POST["email"];
$pass = $_POST["password"];
require "init.php";

$query = "Select * from userinfo where email like '".$email."';";
$result = mysqli_query($con,$query);

if(mysqli_num_rows($result)>0)
{
$response = array();
$code ="login_true";
$row = mysqli_fetch_array($result);
$name = $row[0];
$message ="Login Success ! Welcome ".$name;
array_push($response,array("code"=>$code,"message"=>$message));
echo json_encode(array("server_response"=>$response));  
}
else
{
$response = array();
$code ="login_false";
$message ="Login Failed ! Try Again";
array_push($response,array("code"=>$code,"message"=>$message));
echo json_encode(array("server_response"=>$response));  
}
mysqli_close($con);
?>

01-18 11:11:13.230 1916-1916/? W/dalvikvm: threadid=1: thread exiting with      uncaught exception (group=0xa4d05b20)
01-18 11:11:13.230 1916-1916/? E/AndroidRuntime: FATAL EXCEPTION: main
01-18 11:11:13.230 1916-1916/? E/AndroidRuntime: Process: lk.blood.bloodlk, PID: 1916
01-18 11:11:13.230 1916-1916/? E/AndroidRuntime: java.lang.NullPointerException
01-18 11:11:13.230 1916-1916/? E/AndroidRuntime:     at org.json.JSONTokener.nextCleanInternal(JSONTokener.java:116)
01-18 11:11:13.230 1916-1916/? E/AndroidRuntime:     at org.json.JSONTokener.nextValue(JSONTokener.java:94)
01-18 11:11:13.230 1916-1916/? E/AndroidRuntime:     at org.json.JSONObject.<init>(JSONObject.java:155)
01-18 11:11:13.230 1916-1916/? E/AndroidRuntime:     at org.json.JSONObject.<init>(JSONObject.java:172)
01-18 11:11:13.230 1916-1916/? E/AndroidRuntime:     at lk.blood.bloodlk.BackgroundTask.onPostExecute(BackgroundTask.java:162)
01-18 11:11:13.230 1916-1916/? E/AndroidRuntime:     at lk.blood.bloodlk.BackgroundTask.onPostExecute(BackgroundTask.java:34)
01-18 11:11:13.230 1916-1916/? E/AndroidRuntime:     at android.os.AsyncTask.finish(AsyncTask.java:632)
01-18 11:11:13.230 1916-1916/? E/AndroidRuntime:     at android.os.AsyncTask.access$600(AsyncTask.java:177)
01-18 11:11:13.230 1916-1916/? E/AndroidRuntime:     at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:645)
01-18 11:11:13.230 1916-1916/? E/AndroidRuntime:     at android.os.Handler.dispatchMessage(Handler.java:102)
01-18 11:11:13.230 1916-1916/? E/AndroidRuntime:     at android.os.Looper.loop(Looper.java:136)
01-18 11:11:13.230 1916-1916/? E/AndroidRuntime:     at android.app.ActivityThread.main(ActivityThread.java:5001)
01-18 11:11:13.230 1916-1916/? E/AndroidRuntime:     at java.lang.reflect.Method.invokeNative(Native Method)
01-18 11:11:13.230 1916-1916/? E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Method.java:515)
01-18 11:11:13.230 1916-1916/? E/AndroidRuntime:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
01-18 11:11:13.230 1916-1916/? E/AndroidRuntime:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
01-18 11:11:13.230 1916-1916/? E/AndroidRuntime:     at dalvik.system.NativeStart.main(Native Method)
01-18 11:11:13.546 616-784/? W/ActivityManager:   Force finishing activity lk.blood.bloodlk/.login
01-18 11:11:14.810 616-631/? W/ActivityManager: Activity pause timeout for ActivityRecord{52942fe0 u0 lk.blood.bloodlk/.login t4 f}
01-18 11:11:18.478 295-434/? W/genymotion_audio: out_write() limiting sleep time 46802 to 39909
01-18 11:11:18.758 1916-1916/? I/Process: Sending signal. PID: 1916 SIG: 9
01-18 11:11:19.042 616-666/? I/ActivityManager: Process lk.blood.bloodlk (pid 1916) has died.
01-18 11:11:19.098 616-647/? W/InputDispatcher: channel '529556a4 lk.blood.bloodlk/lk.blood.bloodlk.Home (server)' ~ Consumer closed input channel or an error occurred.  events=0x9
01-18 11:11:19.098 616-647/? E/InputDispatcher: channel '529556a4 lk.blood.bloodlk/lk.blood.bloodlk.Home (server)' ~ Channel is unrecoverably broken and will be disposed!
01-18 11:11:19.102 616-647/? W/InputDispatcher: channel '529857c0 lk.blood.bloodlk/lk.blood.bloodlk.login (server)' ~ Consumer closed input channel or an error occurred.  events=0xd