以下是我的DBHelper.java
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.DatabaseUtils;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import java.util.ArrayList;
import java.util.HashMap;
public class DBHelper extends SQLiteOpenHelper {
public static final String DATABASE_NAME = "contactdb.sqlite";
public static final String CONTACTS_TABLE_NAME = "mycontacts";
public static final String CONTACTS_COLUMN_ID = "id";
public static final String CONTACTS_COLUMN_STUNAME = "name";
public static final String CONTACTS_COLUMN_STUPHONE = "phone";
public static final String CONTACTS_COLUMN_STUSTREET = "street";
public static final String CONTACTS_COLUMN_STUEMAIL = "email";
public static final String CONTACTS_COLUMN_STUCITY = "place";
private HashMap hp;
public DBHelper(Context context)
{
super(context, DATABASE_NAME , null, 3);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(
"create table mycontacts " +
"(id integer primary key autoincrement, name text,phone text,email text, street text,place text)"
);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS mycontacts");
onCreate(db);
}
public boolean addStudentContact(String contactname,String contactphone,String contactstreet,String contactemail, String contactplace){
/*,*/
SQLiteDatabase db=this.getWritableDatabase();
ContentValues contantValues = new ContentValues();
contantValues.put("name",contactname);
contantValues.put("phone", contactphone);
contantValues.put("street",contactstreet);
contantValues.put("email",contactemail);
contantValues.put("place",contactplace);
db.insert("mycontacts", null, contantValues);
db.close();
return true;
}
public boolean updateStudentContact(Integer contactid,String contactname,String contactphone,String contactstreet,String contactemail, String contactplace)
{
/*,String contactname,*/
SQLiteDatabase db=this.getWritableDatabase();
ContentValues contantValues = new ContentValues();
contantValues.put("name",contactname);
contantValues.put("phone", contactphone);
contantValues.put("street",contactstreet);
contantValues.put("email",contactemail);
contantValues.put("place",contactplace);
db.update("mycontacts", contantValues, "id = ?", new String[]{Integer.toString(contactid)});
db.close();
return true;
}
public Integer deleteContact(Integer id){
SQLiteDatabase db=this.getWritableDatabase();
return db.delete("mycontacts","id = ?",new String[]{Integer.toString(id)});
}
public Cursor getData(int contactid){
SQLiteDatabase db=this.getWritableDatabase();
Cursor res=db.rawQuery("Select * from mycontacts where id = " + contactid + "", null);
return res;
}
public int numberOfRows(){
SQLiteDatabase db=this.getWritableDatabase();
int numRows=(int) DatabaseUtils.queryNumEntries(db,CONTACTS_TABLE_NAME);
return numRows;
}
public ArrayList<Person> getAllStudentContacts(){
ArrayList<Person> arraylist= new ArrayList<>();
SQLiteDatabase db=this.getReadableDatabase();
Cursor cursor=db.rawQuery("Select * from mycontacts",null);
if (cursor.moveToFirst()) {
do {
Person person = new Person();
person.name = cursor.getString(cursor.getColumnIndex(CONTACTS_COLUMN_STUNAME));
person.ID = cursor.getInt(cursor.getColumnIndex(CONTACTS_COLUMN_ID));
arraylist.add(person);
} while (cursor.moveToNext());
}
return arraylist;
}
}
DisplayContact.java
package com.test.ppandey.contactapp;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
public class DisplayContact extends AppCompatActivity {
int from_Where_I_Am_Coming = 0;
private DBHelper mydb;
TextView name;
TextView phone;
TextView email;
TextView street;
TextView place;
int id_To_Update = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_display_contact);
name = (TextView) findViewById(R.id.editTextName);
phone = (TextView) findViewById(R.id.editTextPhone);
email = (TextView) findViewById(R.id.editTextStreet);
street = (TextView) findViewById(R.id.editTextEmail);
place = (TextView) findViewById(R.id.editTextCity);
mydb = new DBHelper(this);
Bundle extras = getIntent().getExtras();
{
int Value = extras.getInt("id");
if (Value > 0) {
//means this is the view part not the add contact part.
Cursor rs = mydb.getData(Value);
id_To_Update = Value;
rs.moveToFirst();
String stuname = rs.getString(rs.getColumnIndex(DBHelper.CONTACTS_COLUMN_STUNAME));
String stuphone = rs.getString(rs.getColumnIndex(DBHelper.CONTACTS_COLUMN_STUPHONE));
String stuemail = rs.getString(rs.getColumnIndex(DBHelper.CONTACTS_COLUMN_STUEMAIL));
String stustreet = rs.getString(rs.getColumnIndex(DBHelper.CONTACTS_COLUMN_STUSTREET));
String stuplace = rs.getString(rs.getColumnIndex(DBHelper.CONTACTS_COLUMN_STUCITY));
if (!rs.isClosed()) {
rs.close();
}
Button b = (Button) findViewById(R.id.button1);
b.setVisibility(View.INVISIBLE);
name.setText((CharSequence) stuname);
name.setFocusable(false);
name.setClickable(false);
phone.setText((CharSequence) stuphone);
phone.setFocusable(false);
phone.setClickable(false);
email.setText((CharSequence) stuemail);
email.setFocusable(false);
email.setClickable(false);
street.setText((CharSequence) stustreet);
street.setFocusable(false);
street.setClickable(false);
place.setText((CharSequence) stuplace);
place.setFocusable(false);
place.setClickable(false);
}
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
Bundle extras = getIntent().getExtras();
if (extras != null) {
int Value = extras.getInt("id");
if (Value > 0) {
getMenuInflater().inflate(R.menu.menu_display_contact, menu);
} else {
getMenuInflater().inflate(R.menu.menu_main, menu);
}
}
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
super.onOptionsItemSelected(item);
switch (item.getItemId()) {
case R.id.Edit_Contact:
Button b = (Button) findViewById(R.id.button1);
b.setVisibility(View.VISIBLE);
name.setEnabled(true);
name.setFocusableInTouchMode(true);
name.setClickable(true);
phone.setEnabled(true);
phone.setFocusableInTouchMode(true);
phone.setClickable(true);
email.setEnabled(true);
email.setFocusableInTouchMode(true);
email.setClickable(true);
street.setEnabled(true);
street.setFocusableInTouchMode(true);
street.setClickable(true);
place.setEnabled(true);
place.setFocusableInTouchMode(true);
place.setClickable(true);
return true;
case R.id.Delete_Contact:
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage(R.string.deleteContact)
.setPositiveButton(R.string.yes, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
mydb.deleteContact(id_To_Update);
Toast.makeText(getApplicationContext(), "Deleted Successfully", Toast.LENGTH_SHORT).show();
Intent intent = new Intent(getApplicationContext(), MainActivity.class);
startActivity(intent);
}
})
.setNegativeButton(R.string.no, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
// User cancelled the dialog
}
});
AlertDialog d = builder.create();
d.setTitle("Are you sure ?");
d.show();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
public void saveData(View view) {
/*, */
/* mydb.addContact(name.getText().toString(),email.getText().toString(), street.getText().toString(), place.getText().toString(), phone.getText().toString());
finish();*/
Bundle extras = getIntent().getExtras();
if (extras != null) {
int Value = extras.getInt("id");
if (Value > 0) {
if (mydb.updateStudentContact(id_To_Update, name.getText().toString(), phone.getText().toString(), street.getText().toString(),email.getText().toString(), place.getText().toString())) {
Toast.makeText(getApplicationContext(), "Successfully Updated", Toast.LENGTH_SHORT).show();
Intent intent = new Intent(getApplicationContext(), MainActivity.class);
startActivity(intent);
} else {
Toast.makeText(getApplicationContext(), "Record not updated", Toast.LENGTH_SHORT).show();
}
} else {
if (mydb.addStudentContact(name.getText().toString(), phone.getText().toString(),street.getText().toString(), email.getText().toString(), place.getText().toString())) {
Toast.makeText(getApplicationContext(), "Successfully Added", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(getApplicationContext(), "Record not added", Toast.LENGTH_SHORT).show();
}
Intent intent = new Intent(getApplicationContext(), MainActivity.class);
startActivity(intent);
}
}
}
}
MainActivity.java
package com.test.ppandey.contactapp;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
public final static String EXTRA_MESSAGE="MESSAGE";
private ListView objListView;
DBHelper db;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
db=new DBHelper(this);
ArrayList<Person> arrayList=db.getAllStudentContacts();
ArrayAdapter arrayAdapter=new ArrayAdapter(this,android.R.layout.simple_list_item_1,arrayList);
objListView=(ListView)findViewById(R.id.listView1);
objListView.setAdapter(arrayAdapter);
objListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
long id_to_search = id;
Bundle dataBundle = new Bundle();
dataBundle.putLong("id", id_to_search);
Intent intent = new Intent(getApplicationContext(), DisplayContact.class);
intent.putExtras(dataBundle);
startActivity(intent);
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
/* int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);*/
super.onOptionsItemSelected(item);
switch(item.getItemId())
{
case R.id.item1:Bundle dataBundle = new Bundle();
dataBundle.putInt("id", 0);
Intent intent = new Intent(getApplicationContext(),DisplayContact.class);
intent.putExtras(dataBundle);
startActivityForResult(intent, 0);
return true;
default:
return super.onOptionsItemSelected(item);
}
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
db=new DBHelper(this);
ArrayList<Person> arrayList=db.getAllStudentContacts();
ArrayAdapter arrayAdapter=new ArrayAdapter(this,android.R.layout.simple_list_item_1,arrayList);
objListView=(ListView)findViewById(R.id.listView1);
objListView.setAdapter(arrayAdapter);
}
}
activity_display_contact.xml
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/scrollView1"
>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="350dp"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
tools:context="com.test.ppandey.contactapp.DisplayContact">
<EditText
android:id="@+id/editTextName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_marginTop="5dp"
android:layout_marginLeft="82dp"
android:ems="10"
android:inputType="text" >
</EditText>
<EditText
android:id="@+id/editTextEmail"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/editTextStreet"
android:layout_below="@+id/editTextStreet"
android:layout_marginTop="22dp"
android:ems="10"
android:inputType="textEmailAddress" />
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/editTextName"
android:layout_alignParentLeft="true"
android:text="@string/name"
android:textAppearance="?android:attr/textAppearanceMedium" />
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/editTextCity"
android:layout_alignParentBottom="true"
android:layout_marginBottom="28dp"
android:onClick="saveData"
android:text="@string/save" />
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/editTextEmail"
android:layout_alignLeft="@+id/textView1"
android:text="@string/email"
android:textAppearance="?android:attr/textAppearanceMedium" />
<TextView
android:id="@+id/textView5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/editTextPhone"
android:layout_alignLeft="@+id/textView1"
android:text="@string/phone"
android:textAppearance="?android:attr/textAppearanceMedium" />
<TextView
android:id="@+id/textView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/editTextEmail"
android:layout_alignLeft="@+id/textView5"
android:text="@string/street"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="@+id/editTextCity"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignRight="@+id/editTextName"
android:layout_below="@+id/editTextEmail"
android:layout_marginTop="30dp"
android:ems="10"
android:inputType="text" />
<TextView
android:id="@+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/editTextCity"
android:layout_alignBottom="@+id/editTextCity"
android:layout_alignParentLeft="true"
android:layout_toLeftOf="@+id/editTextEmail"
android:text="@string/country"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="@+id/editTextStreet"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/editTextName"
android:layout_below="@+id/editTextPhone"
android:ems="10"
android:inputType="text" >
<requestFocus />
</EditText>
<EditText
android:id="@+id/editTextPhone"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/editTextStreet"
android:layout_below="@+id/editTextName"
android:ems="10"
android:inputType="phone|text" />
</RelativeLayout>
</ScrollView>
Person.java
package com.test.ppandey.contactapp;
/**
* Created by Ariel on 08/03/2016.
*/
public class Person {
public String name;
public long ID;
private Person person; {
name = new String(name);
}
private Person id; {
ID = new long(id);
}
}
我添加了Person.java并编辑了MainActivity.java和DBHelper.java
答案 0 :(得分:1)
这是你的问题:
int id_to_search = position + 1;
您假设ID和位置同步。只要您不删除任何条目,这只是真实的。
,而不是使用位置来引用条目,你必须使用ID,因为它是不可变的。从数据库中提取条目时,需要提取名称和ID,并将数据保存在适配器中,这样就可以通过ID来引用条目。
下面的一些代码(只是一个骨架):
1)为您的数据创建模型
public class Person {
// consider making private and adding accessors
public String name;
public long id;
}
2)当您提取数据时,请提取名称和ID(您可以展开Person类和此函数以获取其他数据):
public List<Person> getAllStudentContacts(){
List<Person> arraylist= new ArrayList<>();
SQLiteDatabase db=this.getReadableDatabase();
Cursor cursor=db.rawQuery("Select * from mycontacts",null);
if (cursor.moveToFirst()) {
do {
Person person = new Person();
person.name = cursor.getString(cursor.getColumnIndex(CONTACTS_COLUMN_STUNAME));
person.id = cursor.getInt(cursor.getColumIndex(CONTACTS_COLUMN_ID));
arraylist.add(prson);
} while (cursor.moveToNext());
}
return arraylist;
}
然后在适配器中使用Person对象中的ID来引用它,而不是位置。
答案 1 :(得分:-1)
您是否在每次插入/删除时从Android应用程序刷新“名称列表”?
也许通过在每次插入/删除后从代码中调用getAllStudentContacts()来重新填充Android应用程序的名称列表?
祝你好运