Java SQLiteDatabase:Android studio自定义自动增量
我对Android studio和SQLITE数据库非常陌生。我需要以下方面的帮助: 数据库已成功创建并可以显示值。但是,我尝试在创建时为每个患者创建一个自定义的唯一ID。ID应该在000000到999999之间(6位唯一ID) 该应用程序的工作方式是:Java SQLiteDatabase:Android studio自定义自动增量,java,android,sql,sqlite,android-studio,Java,Android,Sql,Sqlite,Android Studio,我对Android studio和SQLITE数据库非常陌生。我需要以下方面的帮助: 数据库已成功创建并可以显示值。但是,我尝试在创建时为每个患者创建一个自定义的唯一ID。ID应该在000000到999999之间(6位唯一ID) 该应用程序的工作方式是: 1. User can "add patient" 2. User enters firstName and lastName 3. User than selects a department from a spinner 4. once t
1. User can "add patient"
2. User enters firstName and lastName
3. User than selects a department from a spinner
4. once the user has completed the above steps, he/she can click "Add Patient"
5. Then the values are displayed in a TabbedView, however the textView is horizontal rather than vertical.
6. and its displayed in a ListView
我已经完成了上述所有步骤。我现在需要帮助为患者创建一个唯一的id。任何帮助都将不胜感激
请查看下面的代码:
PatientDbHelper.java // Creates the tables and database
package tanav.sharma;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
/**
* Created by Tanav on 11/4/2016.
*/
public class PatientDbHelper extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "PATIENTINFO.db";
private static final int DATABASE_VERSION = 1;
private static final String CREATE_QUERY =
"CREATE TABLE "+PatientInfo.NewPatientInfo.TABLE_NAME+" ("+ PatientInfo.NewPatientInfo.PATIENT_FNAME+ " TEXT,"+PatientInfo.NewPatientInfo.PATIENT_LNAME+" TEXT,"+PatientInfo.NewPatientInfo.PATIENT_DEPARTMENT+" TEXT);";
public PatientDbHelper(Context context){
super(context,DATABASE_NAME,null,DATABASE_VERSION);
Log.e("DATABASE OPERATIONS","Database created / opened ...");
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(CREATE_QUERY);
Log.e("DATABASE OPERATIONS","Table created...");
}
public void addInformations(String fname, String lname, String department, SQLiteDatabase db){
ContentValues contentValues = new ContentValues();
contentValues.put(PatientInfo.NewPatientInfo.PATIENT_FNAME,fname);
contentValues.put(PatientInfo.NewPatientInfo.PATIENT_LNAME,lname);
contentValues.put(PatientInfo.NewPatientInfo.PATIENT_DEPARTMENT,department);
db.insert(PatientInfo.NewPatientInfo.TABLE_NAME, null,contentValues);
Log.e("DATABASE OPERATIONS","One in row inserted...");
}
public Cursor getInformations(SQLiteDatabase db){
Cursor cursor;
String[] projections = {PatientInfo.NewPatientInfo.PATIENT_FNAME, PatientInfo.NewPatientInfo.PATIENT_LNAME, PatientInfo.NewPatientInfo.PATIENT_DEPARTMENT};
cursor = db.query(PatientInfo.NewPatientInfo.TABLE_NAME,projections,null,null,null,null,null);
return cursor;
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}
PatientInfo.java//这是列等的名称
package tanav.sharma;
/**
* Created by Tanav on 11/4/2016.
*/
public class PatientInfo {
public static abstract class NewPatientInfo{
//public static final String PATIENT_ID = "patient_id";
public static final String PATIENT_FNAME = "patient_fname";
public static final String PATIENT_LNAME = "patient_lname";
public static final String PATIENT_DEPARTMENT = "patient_department";
public static final String TABLE_NAME = "patient_info";
}
}
PatientInfoProvider.java
package tanav.sharma;
/**
* Created by Tanav on 11/4/2016.
*/
public class PatientInfoProvider {
private String fname;
private String lname;
private String departments;
public PatientInfoProvider(String fname, String lname, String departments){
this.fname = fname;
this.lname = lname;
this.departments = departments;
}
public String getLname() {
return lname;
}
public void setLname(String lname) {
this.lname = lname;
}
public String getDepartments() {
return departments;
}
public void setDepartments(String departments) {
this.departments = departments;
}
public String getFname() {
return fname;
}
public void setFname(String fname) {
this.fname = fname;
}
}
以下文件用于在具有customText视图的listView中显示值
PatientAdapter.java
package tanav.sharma;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.List;
/**
* Created by Tanav on 11/4/2016.
*/
public class PatientAdapter extends ArrayAdapter {
List list = new ArrayList();
public PatientAdapter(Context context, int resource) {
super(context, resource);
}
static class LayoutHandler{
TextView FNAME,LNAME,Department;
}
@Override
public void add(Object object) {
super.add(object);
list.add(object);
}
@Override
public int getCount() {
return list.size();
}
@Override
public Object getItem(int position) {
return list.get(position);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View row = convertView;
LayoutHandler layoutHandler;
if(row == null){
LayoutInflater layoutInflater = (LayoutInflater)this.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
row = layoutInflater.inflate(R.layout.display_all_patients,parent,false);
layoutHandler = new LayoutHandler();
layoutHandler.FNAME = (TextView)row.findViewById(R.id.patientNameFirst);
layoutHandler.LNAME = (TextView)row.findViewById(R.id.patientNameLast);
layoutHandler.Department = (TextView) row.findViewById(R.id.patientDepartment);
row.setTag(layoutHandler);
}else{
layoutHandler = (LayoutHandler)row.getTag();
}
PatientInfoProvider patientInfoProvider = (PatientInfoProvider)this.getItem(position);
layoutHandler.FNAME.setText(patientInfoProvider.getFname());
layoutHandler.LNAME.setText(patientInfoProvider.getLname());
layoutHandler.Department.setText(patientInfoProvider.getDepartments());
return row;
}
}
1-通过java中的random()类生成一个随机数。
2-如果此编号存在,则在数据库中搜索生成新编号如果不存在,则插入具有此编号的数据
注意:字段ID是主字段,但不是在自动递增中 自动增量的目的是防止重用以前删除的行的ID PatientInfo.java ID列必须是表的第一列:
public static final String PATIENT_ID = "_id";
PatientDbHelper.java
private static final String CREATE_QUERY = "CREATE TABLE " + PatientInfo.NewPatientInfo.TABLE_NAME + " ("
+ PatientInfo.NewPatientInfo.PATIENT_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
+ PatientInfo.NewPatientInfo.PATIENT_FNAME+ " TEXT,"
+ PatientInfo.NewPatientInfo.PATIENT_LNAME+" TEXT,"
+ PatientInfo.NewPatientInfo.PATIENT_DEPARTMENT+" TEXT);";
补充资料()
PatientInfoProvider.java
private int id;
及
或/或更改构造函数
public PatientInfoProvider(int id, String fname, String lname, String departments){
this.id = id;
this.fname = fname;
this.lname = lname;
this.departments = departments; }
你必须在某个地方填写ID字段。如果需要,我可以将整个PatientInfoProvider.java
package tanav.sharma;
/**
* Created by Tanav on 11/4/2016.
*/
public class PatientInfoProvider {
private String fname;
private String lname;
private String departments;
public PatientInfoProvider(String fname, String lname, String departments){
this.fname = fname;
this.lname = lname;
this.departments = departments;
}
public String getLname() {
return lname;
}
public void setLname(String lname) {
this.lname = lname;
}
public String getDepartments() {
return departments;
}
public void setDepartments(String departments) {
this.departments = departments;
}
public String getFname() {
return fname;
}
public void setFname(String fname) {
this.fname = fname;
}
}
好的,那么我的附加信息()会像这样吗
public void addInformations(int id, String fname, String lname, String department, SQLiteDatabase db){
ContentValues contentValues = new ContentValues();
if ( id != 0 ) contentValues.put(PatientInfo.NewPatientInfo.PATIENT_ID, id);
contentValues.put(PatientInfo.NewPatientInfo.PATIENT_FNAME,fname);
contentValues.put(PatientInfo.NewPatientInfo.PATIENT_LNAME,lname);
contentValues.put(PatientInfo.NewPatientInfo.PATIENT_DEPARTMENT,department);
db.insert(PatientInfo.NewPatientInfo.TABLE_NAME, null,contentValues);
Log.e("DATABASE OPERATIONS","One in row inserted...");
}
此外,它还提供了以下错误:
Error:(50, 28) error: method addInformations in class PatientDbHelper cannot be applied to given types;
required: int,String,String,String,SQLiteDatabase
found: String,String,String,SQLiteDatabase
reason: actual and formal argument lists differ in length
因此,我尝试通过在代码中应用以下行来修复它
public void addPatient(View view){
int id; // Added this line
String fname = PatientFirstName.getText().toString();
String lname = PatientLastName.getText().toString();
String dept = departments.getSelectedItem().toString();
patientDbHelper = new PatientDbHelper(this);
sqLiteDatabase = patientDbHelper.getWritableDatabase();
patientDbHelper.addInformations(id,fname,lname,dept,sqLiteDatabase); //added 'id' in arguments..
Toast.makeText(getBaseContext(),"Data Saved",Toast.LENGTH_LONG).show();
patientDbHelper.close();
}
然而,addInformations中的'id'参数带有红色下划线,表示变量可能尚未初始化
我已经把一切都修好了:)。选中_ID。您可以使用
BaseColumns.\u ID
并使其成为INTEGER NOT NULL主键
我将把它放在哪里?在my PatientDbHelper?yes“创建表”+PatientInfo.NewPatientInfo.TABLE_NAME+”(“+BaseColumns._ID+”整数非空主键,”…
好的。有没有办法我可以亲自给你发消息?我还有更多的问题。你可以加入stackoverflow上的聊天室。但是有一些规则需要遵守。你需要问一个新问题,可以吗?我真的需要帮助,我已经4天没有了。我需要另外两个文件才能确定。方法AddInformation()在某个地方调用。有创建新唯一ID的最佳位置。在创建新唯一ID之前,您需要知道当前的最大ID。我也需要此文件来帮助您。否则,您可以将整个项目发送给我。>但是,AddInformation中的“ID”参数带有红色下划线,表示变量可能不是初始变量izedYes,您需要初始化变量“id”。Lool,我最终找到了答案。非常感谢您的帮助
public void addPatient(View view){
int id; // Added this line
String fname = PatientFirstName.getText().toString();
String lname = PatientLastName.getText().toString();
String dept = departments.getSelectedItem().toString();
patientDbHelper = new PatientDbHelper(this);
sqLiteDatabase = patientDbHelper.getWritableDatabase();
patientDbHelper.addInformations(id,fname,lname,dept,sqLiteDatabase); //added 'id' in arguments..
Toast.makeText(getBaseContext(),"Data Saved",Toast.LENGTH_LONG).show();
patientDbHelper.close();
}