所以我正在创建一个简单的联系人应用程序，并坚持在textview中显示更新的行。我在方法“openUpdateDialog”中发表评论，因为我需要帮助解决问题。我希望我的代码易于理解并感谢帮助人员。
MainActivity.java：
public class MainActivity extends AppCompatActivity {
DatabaseHandler handler;
Context context = this;
ListView listView;
String textFromEtNameAdd;
String textFromEtPhoneAdd;
String textFromListViewName;
String textFromListViewPhone;
String textFromListViewID;
Contact singleContact;
int idAsIntegerFromListview;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
listView = (ListView) findViewById(R.id.listview);
if (listView != null) {
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
TextView tvNameFromListView = (TextView) findViewById(R.id.nameID);
TextView tvPhoneFromListView = (TextView) findViewById(R.id.phoneID);
TextView tvIDFromListView = (TextView) findViewById(R.id.rowID);
textFromListViewName = tvNameFromListView.getText().toString();
textFromListViewPhone = tvPhoneFromListView.getText().toString();
textFromListViewID = tvIDFromListView.getText().toString();
idAsIntegerFromListview = Integer.parseInt(textFromListViewID);
singleContact = handler.getContact(id);
openUpdateDialog();
}
});
listView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
@Override
public boolean onItemLongClick(final AdapterView<?> parent, View view, final int position, final long id) {
PopupMenu popup = new PopupMenu(context, view);
popup.getMenuInflater().inflate(R.menu.menu_delete_popup, popup.getMenu());
popup.show();
popup.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
@Override
public boolean onMenuItemClick(MenuItem item) {
switch (item.getItemId()) {
case R.id.deleteItemID:
Contact contact = new Contact(id);
handler.deleteContact(contact);
printDatabase();
break;
}
return true;
}
});
return true;
}
});
}
handler = new DatabaseHandler(this);
printDatabase();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
if (id == R.id.addContactID) {
openAddDialog();
}
return super.onOptionsItemSelected(item);
}
public void printDatabase() {
Cursor c = handler.getAllContacts();
String[] fromColumns = {handler.KEY_NAME, handler.KEY_ID, handler.KEY_PH_NO};
int[] toViews = {R.id.nameID, R.id.rowID, R.id.phoneID};
SimpleCursorAdapter adapter = new SimpleCursorAdapter(this, R.layout.my_custom_listview, c, fromColumns, toViews, 0);
listView.setAdapter(adapter);
}
public void openAddDialog() {
android.app.AlertDialog.Builder makeDialog = new android.app.AlertDialog.Builder(this);
LayoutInflater li = getLayoutInflater();
View viewAdd = li.inflate(R.layout.contacts_add_dialog, null);
makeDialog.setView(viewAdd);
final EditText etNameAdd = (EditText) viewAdd.findViewById(R.id.etNameID);
final EditText etPhoneAdd = (EditText) viewAdd.findViewById(R.id.etPhoneID);
makeDialog.setPositiveButton("Save", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
textFromEtNameAdd = etNameAdd.getText().toString();
textFromEtPhoneAdd = etPhoneAdd.getText().toString();
Contact contact = new Contact(textFromEtNameAdd, textFromEtPhoneAdd);
handler.addContact(contact);
printDatabase();
}
});
makeDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
android.app.AlertDialog ad = makeDialog.create();
ad.show();
}
public void openUpdateDialog() {
android.app.AlertDialog.Builder makeDialog = new android.app.AlertDialog.Builder(this);
LayoutInflater li = getLayoutInflater();
View viewUpdate = li.inflate(R.layout.contacts_add_dialog, null);
makeDialog.setView(viewUpdate);
final EditText etNameUpdate = (EditText) viewUpdate.findViewById(R.id.etNameID);
final EditText etPhoneUpdate = (EditText) viewUpdate.findViewById(R.id.etPhoneID);
final String singleContactName = singleContact.get_name();
final String singleContactPhone = singleContact.get_phone_number();
etNameUpdate.setText(singleContactName);
etPhoneUpdate.setText(singleContactPhone);
makeDialog.setPositiveButton("Save", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
//name and phone goes in the parenthesis but its storing the old value :/
Contact contact = new Contact();
handler.updateContact(contact);
printDatabase();
}
});
makeDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
android.app.AlertDialog ad = makeDialog.create();
ad.show();
}
}
Contact.java：
public class Contact {
long _id;
String _name;
String _phone_number;
public Contact() {
}
public Contact(long _id) {
this._id = _id;
}
public Contact(String _name, String _phone_number) {
this._name = _name;
this._phone_number = _phone_number;
}
public Contact(long _id, String _name, String _phone_number) {
this._id = _id;
this._name = _name;
this._phone_number = _phone_number;
}
public long get_id() {
return _id;
}
public void set_id(long _id) {
this._id = _id;
}
public String get_name() {
return _name;
}
public void set_name(String _name) {
this._name = _name;
}
public String get_phone_number() {
return _phone_number;
}
public void set_phone_number(String _phone_number) {
this._phone_number = _phone_number;
}
@Override
public String toString() {
return _name;
}
}
DatabaseHandler.java：
public class DatabaseHandler extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "contactsManager";
private static final String TABLE_CONTACTS = "contacts";
public static final String KEY_ID = "_id";
public static final String KEY_NAME = "name";
public static final String KEY_PH_NO = "phone_number";
public DatabaseHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_CONTACTS + "("
+ KEY_ID + " INTEGER PRIMARY KEY," + KEY_NAME + " TEXT,"
+ KEY_PH_NO + " TEXT" + ")";
db.execSQL(CREATE_CONTACTS_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed
db.execSQL("DROP TABLE IF EXISTS " + TABLE_CONTACTS);
onCreate(db);
}
void addContact(Contact contact) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME, contact.get_name());
values.put(KEY_PH_NO, contact.get_phone_number());
db.insert(TABLE_CONTACTS, null, values);
db.close();
}
public Contact getContact(long id) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(TABLE_CONTACTS, new String[]{KEY_ID,
KEY_NAME, KEY_PH_NO}, KEY_ID + "=?",
new String[]{String.valueOf(id)}, null, null, null, null);
if (cursor != null)
cursor.moveToFirst();
Contact contact = new Contact(Integer.parseInt(cursor.getString(0)),
cursor.getString(1), cursor.getString(2));
return contact;
}
public Cursor getAllContacts() {
List<Contact> contactList = new ArrayList<Contact>();
String selectQuery = "SELECT * FROM " + TABLE_CONTACTS;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
if (cursor.moveToFirst()) {
do {
Contact contact = new Contact();
contact.set_id(Integer.parseInt(cursor.getString(0)));
contact.set_name(cursor.getString(1));
contact.set_phone_number(cursor.getString(2));
contactList.add(contact);
} while (cursor.moveToNext());
}
return cursor;
}
public int updateContact(Contact contact) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME, contact.get_name());
values.put(KEY_PH_NO, contact.get_phone_number());
return db.update(TABLE_CONTACTS, values, KEY_ID + " = ?",
new String[]{String.valueOf(contact.get_id())});
}
public void deleteContact(Contact contact) {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLE_CONTACTS, KEY_ID + " = ?",
new String[]{String.valueOf(contact.get_id())});
db.close();
}
}
答案 0 :(得分：1)
我认为问题是......
singleContact = handler.getContact(id);
您传递给getContact查询的id不是在数据库表中声明的数据库ID。您应该了解此id是适配器ID。 要传递数据库ID，您必须编写查询。首先，您确实按名称获取数据库ID。
并在Contact类构造函数中传递要更新的条目的数据库ID，如..
//name and phone goes in the parenthesis but its storing the old value :/
Contact contact = new Contact(etNameUpdate.getText().toString(), etPhoneUpdate .getText().toString(), id);
handler.updateContact(contact);
答案 1 :(得分：1)
首先更改列表视图onItemClick with below
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
if(parent.getItemAtPosition(position) instanceof Cursor){
Log.e(TAG, "onItemClick: Cursor Object");
Cursor c = (Cursor) parent.getItemAtPosition(position);
if(c != null){
String idd = c.getString(c.getColumnIndex(handler.KEY_ID));
Log.e(TAG, "onItemClick: idd " +idd);
idAsIntegerFromListview = Integer.parseInt(idd);
}
}
singleContact = handler.getContact(idAsIntegerFromListview);
openUpdateDialog();
}
});
然后在方法openUpdateDialog（）中更改如下。
makeDialog.setPositiveButton("Save", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
//name and phone goes in the parenthesis but its storing the old value :/
Contact contact = new Contact();
contact.set_id(idAsIntegerFromListview);
contact.set_name(etNameUpdate.getText().toString());
contact.set_phone_number(etPhoneUpdate.getText().toString());
handler.updateContact(contact);
printDatabase();
}
});
我会尝试你的代码。
答案 2 :(得分：0)
我认为你的更新方法有问题，你在操作前关闭了db。
public int updateContact(Contact contact) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME, contact.get_name());
values.put(KEY_PH_NO, contact.get_phone_number());
int noOfUpdatedRow=db.update(TABLE_CONTACTS, values, KEY_ID + " = ?",
new String[]{String.valueOf(contact.get_id())});
db.close();
return noOfUpdatedRow;
}