我正在尝试替换我在Web服务调用中返回的重复记录。我已将数据保存到数据库并尝试执行db.replace。我收到错误java.lang.NullPointerException：尝试在null上调用虚方法'long android.database.sqlite.SQLiteDatabase.replace（java.lang.String，java.lang.String，android.content.ContentValues）'对象参考。
我不确定为什么我得到null，当我调试并通过这些点时，employeeNumber正确填充。所以它不应该创建记录，转到下一个等等，直到它看到相同的employeeNumber，然后删除下一个？
公共类MainActivity扩展了AppCompatActivity {
private ListView mTopList, directReportListView;
private ProgressBar mProgressBar;
private ArrayList<Employee> mEmployees = new ArrayList<>();
private BottomListViewAdapter mBottomListViewAdapter;
EmployeeDBHandler dbHandler;
SQLiteDatabase db;
SimpleCursorAdapter simpleCursorAdapter;
private String startingEmployeeID = employeNumberToRemove;
private String table = "employees";
private static final String KEY_ID = "Employee_number";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
dbHandler = new EmployeeDBHandler(getApplicationContext());
directReportListView = (ListView) findViewById(R.id.mDirectReportList);
mProgressBar = (ProgressBar) findViewById(R.id.progressBar);
mProgressBar.setVisibility(View.VISIBLE);
mBottomListViewAdapter = new BottomListViewAdapter(this, mEmployees);
directReportListView.setAdapter(mBottomListViewAdapter);
getBottomViewXMLData();
// displayTopList(startingEmployeeID);
//displayTopList();
//GUI for seeing android SQLite Database in Chrome Dev Tools
Stetho.InitializerBuilder inBuilder = Stetho.newInitializerBuilder(this);
inBuilder.enableWebKitInspector(Stetho.defaultInspectorModulesProvider(this));
Stetho.Initializer in = inBuilder.build();
Stetho.initialize(in);
}
public void getBottomViewXMLData() {
OkHttpClient client = getUnsafeOkHttpClient();
Request request = new Request.Builder()
.url(getString(R.string.API_FULL_URL))
.build();
client.newCall(request).enqueue(new Callback() {
@Override
public void onFailure(Call call, IOException e) {
e.printStackTrace();
}
@Override
public void onResponse(Call call, final Response response) throws IOException {
final String responseData = response.body().string();
final InputStream stream = new ByteArrayInputStream(responseData.getBytes());
final XMLPullParserHandler parserHandler = new XMLPullParserHandler();
final ArrayList<Employee> employees = (ArrayList<Employee>) parserHandler.parse(stream);
for (Employee e : employees) {
/*String table = "employees";
String whereClause = "Employee_number=?";
String[] whereArgs = new String[] {String.valueOf(startingEmployeeID)};
db = dbHandler.getWritableDatabase();
db.delete(table, whereClause, whereArgs);*/
dbHandler.addEmployee(e);
ContentValues mContentValues = new ContentValues();
mContentValues.put(KEY_ID, startingEmployeeID);
db.replace(table, "Employee_number", mContentValues);
}
mEmployees.clear();
mEmployees.addAll(employees);
//tell adapter on the UI thread its data changed
runOnUiThread(new Runnable() {
@Override
public void run() {
mBottomListViewAdapter.notifyDataSetChanged();
directReportListView.setVisibility(View.VISIBLE);
mProgressBar.setVisibility(View.GONE);
}
});
}
});
}
public void displayTopList(String employeeNumber) {
String table = "employees";
String whereClause = "Employee_number=?";
String[] whereArgs = new String[] {String.valueOf(employeeNumber)};
db = dbHandler.getWritableDatabase();
db.delete(table, whereClause, whereArgs);
// Cursor cursor = (Cursor) dbHandler.getEmployee(startingEmployeeID);
// Log.i("ADAM", cursor.toString());
}
}
public class EmployeeDBHandler extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "OneTeam";
private static final String TABLE_EMPLOYEE = "employees";
//Employee table columns names
private static final String KEY_ID = "Employee_number";
private static final String KEY_FIRST_NAME = "First_name";
private static final String KEY_LAST_NAME = "Last_name";
private static final String KEY_PHONE_NUMBER_MOBILE = "Phone_mobile";
private static final String KEY_PHONE_NUMBER_OFFICE = "Phone_office";
private static final String KEY_PAYROLL_TITLE = "Payroll_title";
private static final String KEY_HAS_DIRECT_REPORTS = "Has_direct_reports";
private static final String KEY_EMAIL = "Email";
private static final String KEY_COST_CENTER = "Cost_center_id";
private static final String KEY_THUMBNAIL_IMAGE = "ThumbnailData";
public EmployeeDBHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
String CREATE_EMPLOYEE_TABLE = "CREATE TABLE IF NOT EXISTS " + TABLE_EMPLOYEE + "("
+ KEY_ID + " STRING PRIMARY KEY,"
+ KEY_FIRST_NAME + " TEXT,"
+ KEY_LAST_NAME + " TEXT,"
+ KEY_PHONE_NUMBER_MOBILE + " TEXT,"
+ KEY_PHONE_NUMBER_OFFICE + " TEXT,"
+ KEY_PAYROLL_TITLE + " TEXT,"
+ KEY_HAS_DIRECT_REPORTS + " TEXT,"
+ KEY_EMAIL + " TEXT,"
+ KEY_THUMBNAIL_IMAGE + " TEXT,"
+ KEY_COST_CENTER + " TEXT" + ")";
db.execSQL(CREATE_EMPLOYEE_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
//drop old table if existence
db.execSQL("DROP TABLE IF EXISTS " + TABLE_EMPLOYEE);
//Create table again
onCreate(db);
}
//Add new employee
public boolean addEmployee(Employee employee) {
SQLiteDatabase database = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_ID, employee.getEmployee_number());
values.put(KEY_FIRST_NAME, employee.getFirst_name());
values.put(KEY_LAST_NAME, employee.getLast_name());
values.put(KEY_PHONE_NUMBER_MOBILE, employee.getPhone_mobile());
values.put(KEY_PHONE_NUMBER_OFFICE, employee.getPhone_office());
values.put(KEY_HAS_DIRECT_REPORTS, employee.getHas_direct_reports());
values.put(KEY_EMAIL, employee.getEmail());
values.put(KEY_COST_CENTER, employee.getCost_center_id());
values.put(KEY_PAYROLL_TITLE, employee.getPayroll_title());
values.put(KEY_THUMBNAIL_IMAGE, employee.getThumbnailData());
//Inserting Row
database.insert(TABLE_EMPLOYEE, null, values);
database.close();
return true;
}
//Get single employee
public Employee getEmployee(int employeeNumber) {
SQLiteDatabase database = this.getReadableDatabase();
Employee employee = null;
Cursor cursor = database.query(TABLE_EMPLOYEE, new String[] {
KEY_ID, KEY_FIRST_NAME, KEY_LAST_NAME, KEY_PHONE_NUMBER_OFFICE, KEY_PHONE_NUMBER_MOBILE,
KEY_HAS_DIRECT_REPORTS, KEY_EMAIL, KEY_COST_CENTER, KEY_PAYROLL_TITLE, KEY_THUMBNAIL_IMAGE}, KEY_ID + "=?",
new String[]{ String.valueOf(employeeNumber)}, null, null, null, null);
if(cursor != null) {
if(cursor.moveToFirst()) {
employee = new Employee(cursor.getString(0),
cursor.getString(1), cursor.getString(2), cursor.getString(3), cursor.getString(4),
cursor.getString(5), cursor.getString(6), cursor.getString(7), cursor.getString(8),
cursor.getString(9), cursor.getString(10), cursor.getString(11), cursor.getString(12),
cursor.getString(12), cursor.getString(14), cursor.getString(15), cursor.getString(16),
cursor.getString(17), cursor.getString(18), cursor.getString(19), cursor.getString(20),
cursor.getString(21), cursor.getString(22), cursor.getString(23), cursor.getString(24),
cursor.getString(24), cursor.getString(25), cursor.getString(26));
}
}
cursor.close();
database.close();
return employee;
}
//Get All Employees
public ArrayList<Employee> getAllEmployees() {
ArrayList<Employee> employeeList = new ArrayList<>();
//Select all query
String selectQuery = "SELECT * FROM " + TABLE_EMPLOYEE;
SQLiteDatabase database = this.getWritableDatabase();
Cursor cursor = database.rawQuery(selectQuery, null);
//looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
Employee employee = new Employee();
employee.setEmployee_number(cursor.getString(cursor.getColumnIndex(KEY_ID)));
employee.setFirst_name(cursor.getString(cursor.getColumnIndex(KEY_FIRST_NAME)));
employee.setLast_name(cursor.getString(cursor.getColumnIndex(KEY_LAST_NAME)));
employee.setPhone_office(cursor.getString(cursor.getColumnIndex(KEY_PHONE_NUMBER_MOBILE)));
employee.setPhone_mobile(cursor.getString(cursor.getColumnIndex(KEY_PHONE_NUMBER_OFFICE)));
employee.setHas_direct_reports(cursor.getString(cursor.getColumnIndex(KEY_HAS_DIRECT_REPORTS)));
employee.setEmail(cursor.getString(cursor.getColumnIndex(KEY_EMAIL)));
employee.setCost_center_id(cursor.getString(cursor.getColumnIndex(KEY_COST_CENTER)));
employee.setPayroll_title(cursor.getString(cursor.getColumnIndex(KEY_PAYROLL_TITLE)));
employee.setThumbnailData(cursor.getString(cursor.getColumnIndex(KEY_THUMBNAIL_IMAGE)));
} while (cursor.moveToNext());
}
//return employees list
return employeeList;
}
//Get Employee Count
public int getEmployeeCount() {
String countQuery = "SELECT * FROM " + TABLE_EMPLOYEE;
SQLiteDatabase database = this.getReadableDatabase();
Cursor cursor = database.rawQuery(countQuery, null);
cursor.close();
return cursor.getCount();
}
//Updating single employee
public int updateEmployee(Employee employee){
SQLiteDatabase database = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_FIRST_NAME, employee.getFirst_name());
values.put(KEY_LAST_NAME, employee.getLast_name());
values.put(KEY_PHONE_NUMBER_MOBILE, employee.getPhone_mobile());
values.put(KEY_PHONE_NUMBER_OFFICE, employee.getPhone_office());
values.put(KEY_HAS_DIRECT_REPORTS, employee.getHas_direct_reports());
values.put(KEY_EMAIL, employee.getEmail());
values.put(KEY_COST_CENTER, employee.getCost_center_id());
values.put(KEY_PAYROLL_TITLE, employee.getPayroll_title());
values.put(KEY_THUMBNAIL_IMAGE, employee.getThumbnailData());
return database.update(TABLE_EMPLOYEE, values, KEY_ID + " = ?",
new String[] {String.valueOf(employee.getEmployee_number())});
}
//Delete single employee
public void deleteEmployee(Employee employee) {
SQLiteDatabase database = this.getWritableDatabase();
database.delete(TABLE_EMPLOYEE, KEY_ID + " = ?",
new String[] {String.valueOf(employee.getEmployee_number())});
database.close();
}
}
答案 0 :(得分：2)
您可以使用database.replace（）方法而不是database.insert（）。
它将根据您的主键在内部检查是否存在前一行？如果是，则它将更新同一行或否，然后它将插入新行。
public boolean addEmployee(Employee employee) {
SQLiteDatabase database = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_ID, employee.getEmployee_number());
values.put(KEY_FIRST_NAME, employee.getFirst_name());
values.put(KEY_LAST_NAME, employee.getLast_name());
values.put(KEY_PHONE_NUMBER_MOBILE, employee.getPhone_mobile());
values.put(KEY_PHONE_NUMBER_OFFICE, employee.getPhone_office());
values.put(KEY_HAS_DIRECT_REPORTS, employee.getHas_direct_reports());
values.put(KEY_EMAIL, employee.getEmail());
values.put(KEY_COST_CENTER, employee.getCost_center_id());
values.put(KEY_PAYROLL_TITLE, employee.getPayroll_title());
values.put(KEY_THUMBNAIL_IMAGE, employee.getThumbnailData());
//Inserting Row
database.replace(TABLE_EMPLOYEE, null, values);
database.close();
return true;
}
将您的添加员工方法更新为
for (Employee e : employees) {
dbHandler.addEmployee(e);
}
从活动到此
的循环