android - 如何在 TextView 中显示更新的行？

Question

因此，我正在创建一个简单的联系人应用程序，但一直无法在 TextView 中显示更新的行。我在方法“openUpdateDialog”中发表了评论，因为存在我需要帮助的问题。我希望我的代码易于理解，并感谢您的帮助。

主要 Activity .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();


}


}

联系人.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;
}
}

数据库处理器.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();
}


}

Answer 1

首先用下面的改变 ListView onItemClick

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();

                }
            });

然后改变方法 openUpdateDialog() 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();


            }
        });

我试过你的代码，它会起作用。