错误是我获取设备IMEI的方式。这个问题的长度或程序给我带来了麻烦。建议一个更好的方法？
这里是错误日志：后跟代码。
E/Volley: [353] NetworkDispatcher.run: Unhandled exception
java.lang.NullPointerException: Attempt to invoke virtual method 'int
java.lang.String.length()' on a null object reference
java.lang.NullPointerException: Attempt to invoke virtual method 'int
java.lang.String.length()' on a null object reference
at libcore.net.UriCodec.encode(UriCodec.java:132)
at java.net.URLEncoder.encode(URLEncoder.java:57)
at com.android.volley.Request.encodeParameters(Request.java:450)
at com.android.volley.Request.getBody(Request.java:436)
at
com.android.volley.toolbox.HurlStack.addBodyIfExists(HurlStack.java:260)
at
com.android.volley.toolbox.HurlStack.setConnectionParametersForRequest（HurlStack.java:234） 在com.android.volley.toolbox.HurlStack.performRequest（HurlStack.java:107） 在com.android.volley.toolbox.BasicNetwork.performRequest（BasicNetwork.java:96） 在com.android.volley.NetworkDispatcher.run（NetworkDispatcher.java:112）
package com.medref;
import android.Manifest;
import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.design.widget.FloatingActionButton;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.telephony.TelephonyManager;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.Spinner;
import android.widget.Toast;
import com.android.volley.AuthFailureError;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.HashMap;
import java.util.Map;
public class Signup extends AppCompatActivity{
Spinner spinner, date, month, year;
EditText Username, Password, Phnumber;
FloatingActionButton Signup;
RadioGroup radioGroup;
RadioButton radioButton;
String Selecteddates, Selectedyear;
String Dob;
String m_deviceId;
String Bloodgroups[] = new String[]{"Not Known","O+","O-","A+","A-","B+","B-","AB+","AB-"};
String dates[] = new String[]{"Day","31", "30", "29","28", "27", "26", "25", "24", "23", "22", "21", "20", "19", "18",
"17", "16", "15", "14", "13", "12", "11", "10", "9", "8", "7", "6", "5", "4", "3", "2", "1"};
String months[] = new String[]{"Month","01", "02", "03", "04", "05", "06", "07", "08",
"09", "10", "11", "12"};
ArrayAdapter<String> adapter, dayAdapter, MonthAdapter;
String userName, phNumber, password, gender, bloodGroup;
String monthtonumber = "";
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.signup);
try{
TelephonyManager TelephonyMgr = (TelephonyManager)getSystemService(TELEPHONY_SERVICE);
m_deviceId = TelephonyMgr.getDeviceId();
}catch (Exception e){}
spinner = (Spinner) findViewById(R.id.spinner);
date = (Spinner) findViewById(R.id.date);
month = (Spinner) findViewById(R.id.month);
year = (Spinner) findViewById(R.id.year);
Username = (EditText) findViewById(R.id.Username);
Password = (EditText) findViewById(R.id.Password);
Phnumber = (EditText) findViewById(R.id.PhNumber);
radioGroup = (RadioGroup) findViewById(R.id.gender);
Signup = (FloatingActionButton) findViewById(R.id.Signup);
adapter = new ArrayAdapter(Signup.this, R.layout.support_simple_spinner_dropdown_item, Bloodgroups);
spinner.setAdapter(adapter);
dayAdapter = new ArrayAdapter(Signup.this, R.layout.support_simple_spinner_dropdown_item, months);
date.setAdapter(dayAdapter);
MonthAdapter = new ArrayAdapter(Signup.this, R.layout.support_simple_spinner_dropdown_item, dates);
month.setAdapter(MonthAdapter);
////////adding years to the array through a loop
ArrayList<String> years = new ArrayList<>();
years.add("Year");
int thisYear = Calendar.getInstance().get(Calendar.YEAR);
for (int i = 1960; i <= thisYear; i++) {
years.add(Integer.toString(i));
}
ArrayAdapter<String> adapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_item, years);
year.setAdapter(adapter);
Signup.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if(getVerification()){
//Getting RadioButton Id
int id = radioGroup.getCheckedRadioButtonId();
radioButton = (RadioButton) findViewById(id);
gender = radioButton.getText().toString();
/////COncatinating DOb
Dob = Selectedyear+"-"+Selecteddates+"-"+monthtonumber;
//Getting all the field valuesn
userName = Username.getText().toString().trim();
phNumber = Phnumber.getText().toString().trim();
password = Password.getText().toString().trim();
try {
//Now we have everything, lets send the data to our database
String url = "http://192.168.1.9/loginfiles/sendvalues.php";
StringRequest stringRequest = new StringRequest(Request.Method.POST, url,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
if (response.equals("10")) {
Toast.makeText(Signup.this, "No connection"
, Toast.LENGTH_SHORT).show();
} else {
Intent i = new Intent(com.medref.Signup.this, MainActivity.class);
startActivity(i);
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(Signup.this, error.getMessage(), Toast.LENGTH_SHORT).show();
}
}) {
@Override
protected Map<String, String> getParams() throws AuthFailureError {
Map<String, String> params = new HashMap<>();
params.put("name", userName);
params.put("number", phNumber);
params.put("password", password);
params.put("dob", Dob);
params.put("gender", gender);
params.put("bloodGroup", bloodGroup);
params.put("deviceid", m_deviceId);
return params;
}
};
RequestQueue requestQueue = Volley.newRequestQueue(Signup.this);
requestQueue.add(stringRequest);
}catch (Exception e){
Toast.makeText(com.medref.Signup.this, e.getMessage(),Toast.LENGTH_LONG).show();
}
}else{
Toast.makeText(Signup.this, "Please fill out the form", Toast.LENGTH_SHORT).show();
}
}
});
spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
bloodGroup = parent.getItemAtPosition(position).toString();
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
}
});
date.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
Selecteddates = parent.getItemAtPosition(position).toString();
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
}
});
month.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
monthtonumber = parent.getItemAtPosition(position).toString();
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
}
});
year.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
Selectedyear= parent.getItemAtPosition(position).toString();
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
}
});
}
protected boolean getVerification(){
if(Username.getText().toString().trim().equals("")){
Username.setError("Empty");
return false;
}else if(Phnumber.getText().toString().trim().equals("")){
Phnumber.setError("Empty");
return false;
}else if(Password.getText().toString().trim().equals("")){
Password.setError("Empty");
return false;
}else if(Selecteddates.equals("") || Selectedyear.equals("")){
return false;
}else{
return true;
}
}
}
答案 0 :(得分：-1)
您无法将响应字符串与“10”进行比较。首先你应该声明
JSONObject jObj = new JSONObject(response);
然后使用getString方法获取您的JSON值。
String variable = jObj.getString("some_var");
if (variable.equals("10")) { ... }
无论如何，这仍然不是你的错误发生的原因。
尝试删除此行并检查错误是否仍然显示：
Toast.makeText(Signup.this, error.getMessage(), Toast.LENGTH_SHORT).show();
请编辑您的问题并添加完整的错误日志。