Question

以下是我的代码，但我如何在另一个活动/类中显示数据库项？我真的想知道如何在另一个活动中显示已添加到数据库的所有内容。谢谢！

主要活动：

public class StartingActivity extends ActionBarActivity {


ArrayList<String> nameList = new ArrayList<String>();
// Gender: 0=Male, 1=Female
int tier, gender;
DBAdapter db = new DBAdapter(this);

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_starting);
    EditText editName = (EditText) findViewById(R.id.editName);
    EditText editTier = (EditText) findViewById(R.id.editTier);
    EditText editDate = (EditText) findViewById(R.id.editDate);

    editName.setHint("Enter athlete's name");
    editTier.setHint("Enter athlete's tier");
    editDate.setHint("Enter date");
}
// Creates database Adapter

public void getAllRecords() {
// Get all records
db.open();
Cursor c = db.getAllRecords();
if(c.moveToFirst())

{
    do {
        DisplayRecord(c);
    } while (c.moveToNext());
}
db.close();
}
public void getRecord(Cursor c) {
    // Get Specific athlete
    db.open();
    Cursor cursor = db.getRecord(1);
    if (c.moveToFirst()) {
        DisplayRecord(c);
    } else {
        Toast.makeText(this, "No athlete found!", Toast.LENGTH_LONG).show();
    }
    db.close();
}
    public void deleteRecord(Cursor c) {

        // Delete Specific athlete
        db.open();
        if (db.deleteRecord(1)) {
            Toast.makeText(this, "Deleted athlete!", Toast.LENGTH_LONG).show();
        } else {
            Toast.makeText(this, "Delete failed!", Toast.LENGTH_LONG).show();
        }
    }

public void onClick_btnConfirm(View view) {

    final RadioButton rdbMale = (RadioButton) findViewById(R.id.rbMale);
    final RadioButton rdbFemale = (RadioButton) findViewById(R.id.rbFemale);
    EditText editName = (EditText) findViewById(R.id.editName);
    EditText editTier = (EditText) findViewById(R.id.editTier);
    EditText editDate = (EditText) findViewById(R.id.editDate);

    TextView textOutput = (TextView) findViewById(R.id.textOutput);
    Intent intentList = new Intent(StartingActivity.this, ListActivity.class);



    // Checks if Edit name has anything filled in. If not, then pop up displays.
    if (editName.getText().length() == 0 || editTier.getText().length() == 0 || editDate.getText().length() == 0) {
        Toast.makeText(this, "Please fill out above fields",
                Toast.LENGTH_LONG).show();
    } else {
        Toast.makeText(this, "Name, date, and tier has been added to list", Toast.LENGTH_LONG).show();
    }

    if (rdbMale.isChecked()) {
        gender = 0;
    }
    if (rdbFemale.isChecked()) {
        gender = 1;
    }
    DBAdapter db = new DBAdapter(this);
    db.open();
    long id = db.insertRecord(editName.getText().toString(), editTier.getText().toString(), editDate.getText().toString(),
            gender);
    db.close();
}
public void DisplayRecord(Cursor c)
{
    Toast.makeText(this,
            "id: " + c.getString(0) + "\n" +
                    "Name: " + c.getString(1) + "\n" +
                    "Tier: " + c.getString(2) + "\n" +
                    "Date: " + c.getString(3) + "\n" +
                    "Gender: " + c.getString(4) + "\n", Toast.LENGTH_LONG).show();
}

public void onClick_btnList(View view) {
    Intent intent = new Intent(getApplicationContext(), ListActivity.class);
    startActivity(intent);
}

}

列出活动：

public class ListActivity extends ActionBarActivity {

DBAdapter db = new DBAdapter(this);

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_list);


    TextView textList = (TextView) findViewById(R.id.textList);
    db.getAllRecords();
}

}

数据库很好，但现在是：

public class DBAdapter {
public static final String KEY_ROWID = "id";
public static final String KEY_NAME = "name";
public static final String KEY_TIER = "tier";
public static final String KEY_DATE = "date";
public static final String KEY_GENDER = "gender";
private static final String TAG = "DBAdapter";

private static final String DATABASE_NAME = "athleteDB";
private static final String DATABASE_TABLE = "myTable";
private static final int DATABASE_VERSION = 2;

private static final String DATABASE_CREATE =
        "create table if not exists assignments (id integer primary key autoincrement, "
                + "name VARCHAR not null, tier VARCHAR, date date, gender VARCHAR );";

private final Context context;

private DatabaseHelper DBHelper;
private SQLiteDatabase db;

public DBAdapter(Context ctx)
{
    this.context = ctx;
    DBHelper = new DatabaseHelper(context);
}

private static class DatabaseHelper extends SQLiteOpenHelper
{
    DatabaseHelper(Context context)
    {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db)
    {
        try {
            db.execSQL(DATABASE_CREATE);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
    {
        Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
                + newVersion + ", which will destroy all old data");
        db.execSQL("DROP TABLE IF EXISTS contacts");
        onCreate(db);
    }
}

//---opens the database---
public DBAdapter open() throws SQLException
{
    db = DBHelper.getWritableDatabase();
    return this;
}

//---closes the database---
public void close()
{
    DBHelper.close();
}

//---insert a record into the database---
public long insertRecord(String name, String tier, String date, int gender)
{
    ContentValues initialValues = new ContentValues();
    initialValues.put(KEY_NAME, name);
    initialValues.put(KEY_TIER, tier);
    initialValues.put(KEY_DATE, date);
    initialValues.put(KEY_GENDER, gender);
    return db.insert(DATABASE_TABLE, null, initialValues);
}

//---deletes a particular record---
public boolean deleteRecord(long rowId)
{
    return db.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null) > 0;
}

//---retrieves all the records---
public Cursor getAllRecords()
{
    return db.query(DATABASE_TABLE, new String[] {KEY_ROWID, KEY_NAME,
            KEY_TIER, KEY_DATE, KEY_GENDER}, null, null, null, null, null);
}

//---retrieves a particular record---
public Cursor getRecord(long rowId) throws SQLException
{
    Cursor mCursor =
            db.query(true, DATABASE_TABLE, new String[] {KEY_ROWID,
                            KEY_NAME, KEY_TIER, KEY_DATE, KEY_GENDER},
                    KEY_ROWID + "=" + rowId, null, null, null, null, null);
    if (mCursor != null) {
        mCursor.moveToFirst();
    }
    return mCursor;
}

//---updates a record---
public boolean updateRecord(long rowId, String name, String tier, String date, int gender)
{
    ContentValues args = new ContentValues();
    args.put(KEY_NAME, name);
    args.put(KEY_TIER, tier);
    args.put(KEY_DATE, date);
    args.put(KEY_GENDER, gender);
    return db.update(DATABASE_TABLE, args, KEY_ROWID + "=" + rowId, null) > 0;
}

}

Answer 1

你的getAllRecords方法返回一个游标。请参阅以下示例供您参考：首先创建一个保存引用的对象：ex。

     public class Person{
        private int id;
        private String name;
        private String tier;
        private String date;

          //do your constructor and getter setter methods
    }

Cursor rs = mydb.getAllRecords;
       rs.moveToFirst();

       ArrayList<Person> personList = new ArrayList<Person>(); //create an arraylist

        do{ //use a for or while loop

        int id = rs.getString(rs.getColumnIndex(DBHelper.KEY_ROWID));
        String name = rs.getString(rs.getColumnIndex(DBHelper.KEY_NAME)); //get all the table column you need
        String tier = rs.getString(rs.getColumnIndex(DBHelper.KEY_TIER));
        String date = rs.getString(rs.getColumnIndex(DBHelper.KEY_DATE));

        personList.add(new Person(id,name,tier,date));

        }while(rs.moveToNext());




textview.setText(personList.get(0).getname()); //display it

如何显示SQLite数据库

1 个答案: