有人可以帮我检查我的代码有什么问题吗？我有4个，spinner并且它们的值已插入到中SQLite。现在我想将该项目检索到另一个旋转器中，Update.java但得到java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String java.lang.Object.toString()' on a null object reference
spinner
SQLite
Update.java
java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String java.lang.Object.toString()' on a null object reference
我已经检查了每个步骤，但仍然无法找出问题所在。
更新.java
public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); dbHelper = new MyDatabaseHelper(this); setContentView(R.layout.updatepage); final String name = getIntent().getExtras().getString("name1"); final String date=getIntent().getExtras().getString("date1"); final String ID = getIntent().getExtras().getString("ID"); RetrievePage(name,date,ID); } public void addProject1(String c) { project1=(Spinner)findViewById(R.id.spinner8); String[] arr = new String[]{"Pro-XXX-XXX","TRN-XXX-XXX","SRV-XXX-XXX","PRO-REE-BERGARDING","PRO-SKM-SSS","PRO-SKM-DI","PRO-SKM-PACKING","PRO-SIE-AVAGO_S110", "PRO-SIE-BIOCON","PRO-BCM-T13/T17","TRIN-IN_HOUSE","TRIN-EXTERNAL","SRIV-SIE-LEMONGRASS","SRV-PW-SIMOCODE","SRV-REE-SIMOCODE","PRO-SKM-D5","PRO-SKM-DRIOU","PRO-BKI-DESMET", "PRO-BKI-INFINEON","PRO-INH-ANDROID","PRO-BCM-S120","PRO-GAW-OP"}; List<String> list = new ArrayList<String>(); String project11 = c; list.add(project11); for(String s:arr){ if(!list.contains(s)){ list.add(s); } } ArrayAdapter<String> adapter = new ArrayAdapter<String>(UpdatePage.this, android.R.layout.simple_spinner_dropdown_item, list); adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); project1.setAdapter(adapter); } public void addProject2(String d) { project2=(Spinner)findViewById(R.id.spinner9); String[] arr = new String[]{"Pro-XXX-XXX","TRN-XXX-XXX","SRV-XXX-XXX","PRO-REE-BERGARDING","PRO-SKM-SSS","PRO-SKM-DI","PRO-SKM-PACKING","PRO-SIE-AVAGO_S110", "PRO-SIE-BIOCON","PRO-BCM-T13/T17","TRIN-IN_HOUSE","TRIN-EXTERNAL","SRIV-SIE-LEMONGRASS","SRV-PW-SIMOCODE","SRV-REE-SIMOCODE","PRO-SKM-D5","PRO-SKM-DRIOU","PRO-BKI-DESMET", "PRO-BKI-INFINEON","PRO-INH-ANDROID","PRO-BCM-S120","PRO-GAW-OP"}; List<String> list = new ArrayList<String>(); String project22 = d; list.add(project22); for(String s:arr){ if(!list.contains(s)){ list.add(s); } } ArrayAdapter<String> adapter = new ArrayAdapter<String>(UpdatePage.this, android.R.layout.simple_spinner_dropdown_item, list); adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); project2.setAdapter(adapter); } public void addProject3(String e) { project3=(Spinner)findViewById(R.id.spinner13); String[] arr = new String[]{"Pro-XXX-XXX","TRN-XXX-XXX","SRV-XXX-XXX","PRO-REE-BERGARDING","PRO-SKM-SSS","PRO-SKM-DI","PRO-SKM-PACKING","PRO-SIE-AVAGO_S110", "PRO-SIE-BIOCON","PRO-BCM-T13/T17","TRIN-IN_HOUSE","TRIN-EXTERNAL","SRIV-SIE-LEMONGRASS","SRV-PW-SIMOCODE","SRV-REE-SIMOCODE","PRO-SKM-D5","PRO-SKM-DRIOU","PRO-BKI-DESMET", "PRO-BKI-INFINEON","PRO-INH-ANDROID","PRO-BCM-S120","PRO-GAW-OP"}; List<String> list = new ArrayList<String>(); String project33 = e; list.add(project33); for(String s:arr){ if(!list.contains(s)){ list.add(s); } } ArrayAdapter<String> adapter = new ArrayAdapter<String>(UpdatePage.this, android.R.layout.simple_spinner_dropdown_item, list); adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); project3.setAdapter(adapter); } public void addProject4(String f) { project4=(Spinner)findViewById(R.id.spinner14); String[] arr = new String[]{"Pro-XXX-XXX","TRN-XXX-XXX","SRV-XXX-XXX","PRO-REE-BERGARDING","PRO-SKM-SSS","PRO-SKM-DI","PRO-SKM-PACKING","PRO-SIE-AVAGO_S110", "PRO-SIE-BIOCON","PRO-BCM-T13/T17","TRIN-IN_HOUSE","TRIN-EXTERNAL","SRIV-SIE-LEMONGRASS","SRV-PW-SIMOCODE","SRV-REE-SIMOCODE","PRO-SKM-D5","PRO-SKM-DRIOU","PRO-BKI-DESMET", "PRO-BKI-INFINEON","PRO-INH-ANDROID","PRO-BCM-S120","PRO-GAW-OP"}; List<String> list = new ArrayList<String>(); String project44 = f; list.add(project44); for(String s:arr){ if(!list.contains(s)){ list.add(s); } } ArrayAdapter<String> adapter = new ArrayAdapter<String>(UpdatePage.this, android.R.layout.simple_spinner_dropdown_item, list); adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); project4.setAdapter(adapter); } public void RetrievePage(String name,String date, String id) { final String name2 = name; final String date2=date; final String id2 = id; final EditText name3 = (EditText) findViewById(R.id.editText9); final EditText date3 = (EditText) findViewById(R.id.editText12); final EditText per1=(EditText) findViewById(R.id.editText20); final EditText per2=(EditText) findViewById(R.id.editText24); final EditText per3=(EditText) findViewById(R.id.editText28); final EditText per4=(EditText) findViewById(R.id.editText32); database = dbHelper.getWritableDatabase(); c = database.rawQuery("SELECT i.Weather, i.Status,w.Subcontractors, w.NumberOfPerson, w.NumberOfHours, wd.Project, wd.WorkDescription, wd.Per, wd.TimeIn, wd.TimeOut FROM Information i LEFT JOIN WorkForce w ON w.TInfo_id = i._id LEFT JOIN WorkDetails wd ON wd.Twf_id=w._id WHERE i.Name = ? AND i._id= ? ", new String[]{String.valueOf(name2),String.valueOf(id2)}, null); if (c != null) { while (c.moveToNext()) { Details WD = new Details(); String Weather = c.getString(c.getColumnIndexOrThrow(MyDatabaseHelper.Weather)); String Project11=c.getString(c.getColumnIndexOrThrow(MyDatabaseHelper.Project)); String Project22=c.getString(c.getColumnIndexOrThrow(MyDatabaseHelper.Project)); String Project33=c.getString(c.getColumnIndexOrThrow(MyDatabaseHelper.Project)); String Project44=c.getString(c.getColumnIndexOrThrow(MyDatabaseHelper.Project)); String Per1=c.getString(c.getColumnIndexOrThrow(MyDatabaseHelper.Per)); String Per2=c.getString(c.getColumnIndexOrThrow(MyDatabaseHelper.Per)); String Per3=c.getString(c.getColumnIndexOrThrow(MyDatabaseHelper.Per)); String Per4=c.getString(c.getColumnIndexOrThrow(MyDatabaseHelper.Per)); addProject1(Project11); addProject2(Project22); addProject3(Project33); addProject4(Project44); addWeather(Weather); WD.setProject(Project11); WD.setProject(Project22); WD.setProject(Project33); WD.setProject(Project44); WD.setPer(Per1); WD.setPer(Per2); WD.setPer(Per3); WD.setPer(Per4); per1.setText(Per1); per2.setText(Per2); per3.setText(Per3); per4.setText(Per4); } } c.close(); }
错误的LogCat
Process: com.example.project.project, PID: 2364 java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String java.lang.Object.toString()' on a null object reference at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:401) at android.widget.ArrayAdapter.getView(ArrayAdapter.java:369) at android.widget.AbsSpinner.onMeasure(AbsSpinner.java:194) at android.widget.Spinner.onMeasure(Spinner.java:580) at android.support.v7.widget.AppCompatSpinner.onMeasure(AppCompatSpinner.java:410) at android.view.View.measure(View.java:18788) at android.view.ViewGroup.measureChild(ViewGroup.java:5922) at android.view.ViewGroup.measureChildren(ViewGroup.java:5899) at android.widget.AbsoluteLayout.onMeasure(AbsoluteLayout.java:66)
我有一个活动，其中有一个微调器，下面的代码对我来说很好用。
public void addWeather(String a) { weather3 = (Spinner) findViewById(R.id.spinner5); String[] arr = new String[]{"Sunny","Cloudy","Rainy","Thunderstorm"}; List<String> list = new ArrayList<String>(); String weather = a; list.add(weather); for(String s:arr){ if(!list.contains(s)){ list.add(s); } } ArrayAdapter<String> adapter = new ArrayAdapter<String>(UpdatePage.this, android.R.layout.simple_spinner_dropdown_item, list); adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); weather3.setAdapter(adapter); }
addProject*方法之一的参数是null。正如您在摘录中看到的ArrayAdapter.createViewFromResource：
addProject
null
ArrayAdapter.createViewFromResource
T item = getItem(position); if (item instanceof CharSequence) { text.setText((CharSequence)item); } else { text.setText(item.toString()); }
…的check instanceof Charsequence，如果T不是a CharSequence或Tnull ，则返回false 。由于您的适配器类型，String我们可以排除第一种情况。因此，集合中的String之一为null。
instanceof Charsequence
CharSequence
T
String
