编辑 Android 日记条目
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【中文标题】编辑 Android 日记条目【英文标题】:Editing Android diary entries 【发布时间】:2021-10-04 16:51:22 【问题描述】:只是一个简单的问题,我正在创建一个 android 日记应用程序,其中主页包含三个按钮:“新建”用于创建新条目,“全部”用于查看数据库中的所有条目,以及“搜索”搜索匹配某些文本的条目。
当我单击“全部”时,它会将我带到一个新的 Intent,它在 ListView 中显示所有条目。但是,当我单击一个单元格时,它会让我回到“新建”将引导我的意图,但它不能编辑条目,它只显示空白字段,如果我输入,只会创建另一个条目在列表视图中。有人对如何做到这一点有任何想法吗?代码如下:
./Diary Main 用于主页
import android.content.Intent;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ListView;
public class DiaryMain extends AppCompatActivity
private Button showEntries, newEntry, searchEntries;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_diary_main);
showEntries = findViewById(R.id.displayAllBtn);
newEntry = findViewById(R.id.newEntryBtn);
searchEntries = findViewById(R.id.searchBtn);
loadFromDBToMemory();
public void displayEntries(View view)
Intent btnClick = new Intent(this, DiaplayAllEntries.class);
startActivity(btnClick);
public void newEntry(View view)
Intent btnClick = new Intent(this, NoteDetailActivity.class);
startActivity(btnClick);
public void searchEntries(View view)
Intent btnClick = new Intent(this, SearchEntries.class);
startActivity(btnClick);
private void loadFromDBToMemory()
SecondDataBaseHelper secondDataBaseHelper = SecondDataBaseHelper.databaseInstance(this);
secondDataBaseHelper.populateDiaryListArray();
./NoteDetailActivity,用户可以在其中添加新的日记条目:
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.ListView;
public class NoteDetailActivity extends AppCompatActivity
private EditText editID, editSubject, editContent, editDate, editLatitude, editLongitude;
private Diary selectedDiary;
SecondDataBaseHelper secondDataBaseHelper;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_note_detail);
editID = findViewById(R.id.IDEditText);
editSubject = findViewById(R.id.SubjectEditText);
editContent = findViewById(R.id.contentEditText);
editDate = findViewById(R.id.dateEditText);
editLatitude = findViewById(R.id.latitudeEditText);
editLongitude = findViewById(R.id.longitudeEditText);
checkForEdit();
private void checkForEdit()
Intent previousIntent = getIntent();
int passedDiaryID = previousIntent.getIntExtra(Diary.DIARY_EDIT_EXTRA, -1);
selectedDiary = Diary.getDiaryForID(passedDiaryID);
if (selectedDiary != null)
editID.setText(selectedDiary.getId());
editSubject.setText(selectedDiary.getSubject());
editContent.setText(selectedDiary.getContent());
editDate.setText(selectedDiary.getDate());
editLatitude.setText(selectedDiary.getLatitude());
editLongitude.setText(selectedDiary.getLongitude());
public void saveEntry(View view)
SecondDataBaseHelper secondDataBaseHelper = SecondDataBaseHelper.databaseInstance(this);
String id = String.valueOf(editID.getText());
String subject = String.valueOf(editSubject.getText());
String content = String.valueOf(editContent.getText());
String date = String.valueOf(editDate.getText());
String latitude = String.valueOf(editLatitude.getText());
String longitude = String.valueOf(editLongitude.getText());
if (selectedDiary == null)
Diary newDiary = new Diary(id, subject, content, date, latitude, longitude);
Diary.diaryArrayList.add(newDiary);
secondDataBaseHelper.addEntryToDatabase(newDiary);
else
selectedDiary.setId(id);
selectedDiary.setSubject(subject);
selectedDiary.setContent(content);
selectedDiary.setDate(date);
secondDataBaseHelper.addEntryToDatabase(selectedDiary);
finish();
./DisplayAllEntries,用户可以在这里看到所有的日记条目,每个条目都是一个可点击的 ListView 单元格:
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
public class DiaplayAllEntries extends AppCompatActivity
private ListView entryListView;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_diaplay_all_entries);
entryListView = findViewById(R.id.diaryListView);
setDiaryAdapter();
setOnClickListener();
private void setDiaryAdapter()
DiaryAdapter diaryAdapter = new DiaryAdapter(getApplicationContext(), Diary.diaryArrayList);
entryListView.setAdapter(diaryAdapter);
private void setOnClickListener()
entryListView.setOnItemClickListener(new AdapterView.OnItemClickListener()
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id)
Diary selectedEntry = (Diary) entryListView.getItemAtPosition(position);
Intent editNoteIntent = new Intent(getApplicationContext(), NoteDetailActivity.class);
editNoteIntent.putExtra(Diary.DIARY_EDIT_EXTRA, selectedEntry.getId());
startActivity(editNoteIntent);
);
./Diary,是个人日记条目的信息,有getters/setters/etc.
import java.util.ArrayList;
public class Diary
private String id;
private String subject;
private String content;
private String date;
private String latitude;
private String longitude;
public static ArrayList<Diary> diaryArrayList = new ArrayList<>();
public static String DIARY_EDIT_EXTRA = "diaryEdit";
public Diary(String id, String subject, String content, String date, String latitude, String longitude)
this.id = id;
this.subject = subject;
this.content = content;
this.date = date;
this.latitude = latitude;
this.longitude = longitude;
public static Diary getDiaryForID(int passedDiaryID)
for (Diary diary : diaryArrayList)
if (Integer.parseInt((diary.getId())) == passedDiaryID)
return diary;
return null;
public String getId()
return id;
public void setId(String id)
this.id = id;
public String getSubject()
return subject;
public void setSubject(String subject)
this.subject = subject;
public String getContent()
return content;
public void setContent(String content)
this.content = content;
public String getDate()
return date;
public void setDate(String date)
this.date = date;
public String getLatitude()
return latitude;
public void setLatitude(String latitude)
this.latitude = latitude;
public String getLongitude()
return longitude;
public void setLongitude(String longitude)
this.longitude = longitude;
./SecondDataBaseHelper 是项目的数据库:
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class SecondDataBaseHelper extends SQLiteOpenHelper
private static SecondDataBaseHelper secondDataBaseHelper;
SQLiteDatabase db = this.getWritableDatabase();
public final static String DATABASE_NM ="RECORD_OF_USER";
public final static String TABLE_NM ="DATA_OF_USER";
public final static String COL_1 = "ID";
public final static String COL_2 = "SUBJECT";
public final static String COL_3 = "ENTRY";
public final static String COL_4 = "DATE";
public final static String COL_5 = "LATITUDE";
public final static String COL_6 = "LONGITUDE";
public SecondDataBaseHelper(Context context)
super(context, DATABASE_NM, null, 1);
public static SecondDataBaseHelper databaseInstance(Context context)
if (secondDataBaseHelper == null)
secondDataBaseHelper = new SecondDataBaseHelper(context);
return secondDataBaseHelper;
@Override
public void onCreate(SQLiteDatabase db)
db.execSQL("CREATE TABLE IF NOT EXISTS " + TABLE_NM +" (ID TEXT, SUBJECT TEXT, ENTRY TEXT, DATE TEXT, LATITUDE TEXT, LONGITUDE TEXT)");
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
public void addEntryToDatabase(Diary entry)
ContentValues contentValues = new ContentValues();
contentValues.put(COL_1, entry.getId());
contentValues.put(COL_2, entry.getSubject());
contentValues.put(COL_3, entry.getContent());
contentValues.put(COL_4, entry.getDate());
contentValues.put(COL_5, entry.getLatitude());
contentValues.put(COL_6, entry.getLongitude());
db.insert(TABLE_NM, null, contentValues);
public void populateDiaryListArray()
SQLiteDatabase sqLiteDatabase = this.getReadableDatabase();
try (Cursor result = sqLiteDatabase.rawQuery("SELECT * FROM " + TABLE_NM, null))
if (result.getCount() != 0)
while (result.moveToNext())
String id = result.getString(1);
String subject = result.getString(2);
String content = result.getString(3);
String date = result.getString(4);
String latitude = result.getString(5);
String longitude = result.getString(6);
Diary diary = new Diary(id, subject, content, date, latitude, longitude);
Diary.diaryArrayList.add(diary);
public void updateDiaryInDB(Diary entry)
SQLiteDatabase sqLiteDatabase = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put(COL_1, entry.getId());
contentValues.put(COL_2, entry.getSubject());
contentValues.put(COL_3, entry.getContent());
contentValues.put(COL_4, entry.getDate());
contentValues.put(COL_5, entry.getLatitude());
contentValues.put(COL_6, entry.getLongitude());
sqLiteDatabase.update(TABLE_NM, contentValues, COL_1 + " ?= ", new String[]String.valueOf(entry.getId()));
调试一切,我认为问题是 ./DisplayAllEntries 中的 .onItemClick() 或 ./NoteDetailActivity 中的 checkForEdit()。相反,这可能是一个糟糕的架构,所以如果有人对如何单击单个单元格进行编辑有任何想法,我将非常感激!
【问题讨论】:
editNoteIntent.putExtra(Diary.DIARY_EDIT_EXTRA, selectedEntry.getId());
- 你的Diary#getId()
方法返回一个String
,所以你在Intent
上添加了一个String
。但是,在NoteDetailActivity
中,您正在检查int
额外:int passedDiaryID = previousIntent.getIntExtra(Diary.DIARY_EDIT_EXTRA, -1);
。将 ID 作为数字处理可能更有意义。
...我在笑和哭之间,因为这正是我所需要的。哈哈,新手多多指教。同样,我需要使用 Google Maps API 来显示基于纬度/经度输入字符串的地图。我将不得不在应用程序中将它们重新实现为双打,但如果我在显示所有日记条目的“全部”意图中添加一个“地图”按钮,我会遵循类似的内容,其中一旦我点击“地图”,我是否可以自动将这些纬度/经度坐标输入到将它们提交给 API 并返回 ImageView 的新意图中?
在那种情况下,也许吧?这取决于你的意思,具体来说。如果您想开始另一个包含实际地图的Activity
,那么是的,您可以使用相同的机制将坐标传递给下一个Activity
,然后在那里检索它们并将它们交给MapView
(这是 Maps API 的基本 UI 组件,顺便说一句)。相反,如果您只想在同一个Activity
中弹出一个小对话框或窗口,则根本不需要弄乱Intent
,尽管显然会涉及其他一些设置。有意义吗?
当然,Fragment
是一个选项,并且有一些设计为“弹出窗口”的基类可能对您的设计有意义;例如,DialogFragment
、BottomSheetDialogFragment
等。您也可以以某种方式将MapView
整合到Activity
的内容中;例如,直接作为主布局中的抽屉,或者作为底部的工作表等。随着您的使用,您会更好地了解适合给定设置的设置。
嘿,这是一些非常棒的信息。我认为 DialogFragment 可能正是我正在寻找的。再次感谢您的宝贵建议!
【参考方案1】:
Diary
s id 是String
public String getId()
return id;
并且你在Bundle
s extra 中传递了这个值:
editNoteIntent.putExtra(Diary.DIARY_EDIT_EXTRA, selectedEntry.getId());
但在NoteDetailActivity
中,您试图将其读作Integer
int passedDiaryID = previousIntent.getIntExtra(Diary.DIARY_EDIT_EXTRA, -1);
你应该在这里使用getStringExtra
方法,最终如果你需要它作为int
使用Integer.parseInt(...)
【讨论】:
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