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私は連絡先アプリを作成する必要があります。それはデータベース接続を持つ私の最初のアプリです。 読んでみるとたくさん試してみると、読み込みと保存に成功しましたが、データが正しく保存されません。データベースに保存されているデータ形式が正しくありません
私のデータベースビュー： android_db_view
あなたが見ることができるように、フィールドは、Androidのテキストビューの説明のように見えるが。
マイMainActivityクラス：
package com.example.joaoliveira.formdb;
import android.content.DialogInterface;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import java.util.List;
public class MainActivity extends AppCompatActivity
{
private DBHelper dbh;
EditText etName, etAdress, etFirm;
Button btnSave, btnDisplay;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.form);
this.dbh = new DBHelper(this);
etName = findViewById(R.id.etName);
etAdress = findViewById(R.id.etAdress);
etFirm = findViewById(R.id.etFirm);
btnSave = findViewById(R.id.btnSave);
btnDisplay = findViewById(R.id.btnDisplay);
btnSave.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View v)
{
if(etName.length() > 0 && etAdress.length() > 0 && etFirm.length() > 0){
dbh.insert(etName.toString(), etAdress.toString(), etFirm.toString());
AlertDialog.Builder adb = new AlertDialog.Builder(MainActivity.this);
adb.setTitle("Success");
adb.setMessage("Accomplished register!");
adb.show();
etName.setText("");
etAdress.setText("");
etFirm.setText("");
}
else{
AlertDialog.Builder adb = new AlertDialog.Builder(MainActivity.this);
adb.setTitle("You have failed!");
adb.setMessage("All the fields must be filled");
adb.show();
etName.setText("");
etAdress.setText("");
etFirm.setText("");
}
}
});
btnDisplay.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View v)
{
List<Contact> contacts = dbh.queryGetAll();
AlertDialog.Builder adb = new AlertDialog.Builder(MainActivity.this);
try {
for (int i = 0; i < contacts.size(); i++) {
Contact c = contacts.get(i);
adb.setTitle("Contact " + (i+1));
adb.setMessage(c.toString());
adb.show();
adb.setPositiveButton("OK", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface di, int which) {
di.dismiss();
}
});
}
}
catch (Exception e){
adb.setTitle("Oops!");
adb.setMessage("There are no saved contacts to display.");
adb.show();
}
}
});
//dbh.deleteAll();
}
}
マイDBHelperクラス：
package com.example.joaoliveira.formdb;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteStatement;
import java.util.ArrayList;
import java.util.List;
public class DBHelper
{
private static final String DATABASE_NAME = "android_db";
private static final String TABLE_NAME = "Contact";
private static final int DATABASE_VERSION = 1;
private Context context;
private SQLiteDatabase db;
private SQLiteStatement insertStmt;
private static final String INSERT = "insert into " + TABLE_NAME + "(name, adress, firm) values (?, ?, ?)";
public DBHelper (Context context)
{
this.context = context;
OpenHelper openHelper = new OpenHelper(this.context);
this.db = openHelper.getWritableDatabase();
this.insertStmt = this.db.compileStatement(INSERT);
}
public long insert(String name, String adress, String firm)
{
this.insertStmt.bindString(1, name);
this.insertStmt.bindString(2, adress);
this.insertStmt.bindString(3, firm);
return this.insertStmt.executeInsert();
}
public void deleteAll()
{
this.db.delete(TABLE_NAME, null, null);
}
public List<Contact> queryGetAll()
{
List<Contact> list = new ArrayList<>();
try {
Cursor cursor = this.db.query(TABLE_NAME, new String[]{"name", "adress", "firm"}, null, null, null, null, null, null);
int nRecords = cursor.getCount(); //getCursor
if(nRecords != 0) {
cursor.moveToFirst();
do {
Contact contact = new Contact(cursor.getString(0), cursor.getString(1), cursor.getString(2));
list.add(contact);
} while (cursor.moveToNext());
if(cursor != null && !cursor.isClosed()){
cursor.close();
return list;
}
}
else
return null;
}
catch(Exception e) {
return null;
}
return list;
}
private static class OpenHelper extends SQLiteOpenHelper
{
OpenHelper(Context context)
{
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
public void onCreate(SQLiteDatabase db)
{
String sql = "CREATE TABLE IF NOT EXISTS " + TABLE_NAME + " (id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT, adress TEXT, firm TEXT);";
db.execSQL(sql);
}
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
{
db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
onCreate(db);
}
}
}
Contactクラスあなたは私があなたの注意を感謝し、すべての私のコード
package com.example.joaoliveira.formdb;
public class Contact
{
private String name;
private String adress;
private String firm;
public Contact(String name, String adress, String firm)
{
this.name = name;
this.adress = adress;
this.firm = firm;
}
public void setName(String name) {
this.name = name;
}
public void setAdress(String adress) {
this.adress = adress;
}
public void setFirm(String firm) {
this.firm = firm;
}
public String getName() {
return name;
}
public String getAdress() {
return adress;
}
public String getFirm() {
return firm;
}
@Override
public String toString() {
return "Name: " + name +
"Adress: " + adress +
"Firm: " + firm;
}
}
を参照してくださいよ確実にします！