android - 将数据从 SQLite 数据库加载到 ListView

Question

我正在尝试从我的 SQLite 数据库中获取一些数据到我的 ListView 中。现在，当应用程序启动时，我的数据库中的数据正在加载到 Toast 中，所以我相信我在正确的轨道上。我只是无法将数据放入 ListView。我已经看过一些教程，但我仍然不确定。这是我的 OverviewActivity.java 类:

public class OverviewActivity extends ListActivity implements View.OnClickListener {

private DBAdapter dbAdapter;

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


    dbAdapter = new DBAdapter(this);
    dbAdapter.open();

    Cursor c = dbAdapter.getAllValues();


    if (c.moveToFirst()) {
        do {
            DisplayTitle(c);
        } while (c.moveToNext());
    }

}

public void DisplayTitle(Cursor c) {

    Toast.makeText(this,
                    "id: " + c.getString(0) + "\n" +
                    "Number: " + c.getString(1) + "\n" +
                    "Name: " + c.getString(2) + "\n" +
                    "Version:  " + c.getString(3) + "\n" +
                    "Method: " + c.getString(4) + "\n" +
                    "Chain Number: " + c.getString(5) + "\n" +
                    "Caught: " + c.getString(6) + "\n",
            Toast.LENGTH_LONG).show();
}

@Override
public void onClick(View view) {
    //TODO: AUTOGENERATED METHOD
}

@Override
public void onDestroy(){
    super.onDestroy();
    dbAdapter.close();
}

@Override
public boolean onCreateOptionsMenu(Menu menu){
    MenuInflater inflater = getMenuInflater();

    inflater.inflate(R.menu.menu, menu);
    return super.onCreateOptionsMenu(menu);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case R.id.menu_add:
            Intent intent = new Intent(OverviewActivity.this, VersionMethodActivity.class);
            startActivity(intent);
            break;
    }
    return false;
}
}

这是我的 DBAdapter.java 类:

public static final String KEY_ID = "_id";
public static final String KEY_NUMBER = "number";
public static final String KEY_NAME = "name";
public static final String KEY_VERSION = "version";
public static final String KEY_METHOD = "method";
public static final String KEY_CHAIN_NUMBER = "chainNumber";
public static final String KEY_CAUGHT = "caught";
private static final String TAG = "DBAdapter";

private static final String DATABASE_NAME = "Chaining";
private static final String DATABASE_TABLE = "ValuesTable";
private static final int DATABASE_VERSION = 1;

private static final String DATABASE_CREATE =
        "create table " + DATABASE_TABLE + "( " +
                KEY_ID + " integer primary key autoincrement, " +
                KEY_NUMBER + " integer, " +
                KEY_NAME + " text, " +
                KEY_VERSION + " text, " +
                KEY_METHOD + " text, " +
                KEY_CHAIN_NUMBER + " integer, " +
                KEY_CAUGHT + " boolean)";

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)
    {
        db.execSQL(DATABASE_CREATE);
    }

    @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 titles");
        onCreate(db);
    }
}


public DBAdapter open() throws SQLException{
    db = DBHelper.getWritableDatabase();
    return this;
}

public void close(){
    DBHelper.close();
}

public long insertValues(int number, String name, String version, String method, int chainNumber, boolean caught){
    ContentValues initialValues = new ContentValues();
    initialValues.put(KEY_NUMBER, number);
    initialValues.put(KEY_NAME, name);
    initialValues.put(KEY_VERSION, version);
    initialValues.put(KEY_METHOD, method);
    initialValues.put(KEY_CHAIN_NUMBER, chainNumber);
    initialValues.put(KEY_CAUGHT, caught);

    return db.insert(DATABASE_TABLE, null, initialValues);
}

public boolean deleteValues(long rowId){
    return db.delete(DATABASE_TABLE, KEY_ID + " = " + rowId, null) > 0;
}

public Cursor getAllValues(){
    return db.query(DATABASE_TABLE, new String[]{
            KEY_ID,
            KEY_NUMBER,
            KEY_NAME,
            KEY_VERSION,
            KEY_METHOD,
            KEY_CHAIN_NUMBER,
            KEY_CAUGHT},
            null, null, null, null, null);
    }

public Cursor getValues(long rowId) throws SQLException {
    Cursor mCursor =
            db.query(true, DATABASE_TABLE, new String[]{
                            KEY_ID,
                            KEY_NUMBER,
                            KEY_NAME,
                            KEY_VERSION,
                            KEY_METHOD,
                            KEY_CHAIN_NUMBER,
                            KEY_CAUGHT},
                    KEY_ID + " = " + rowId,
                    null, null, null, null, null);

    if (mCursor != null){
        mCursor.moveToFirst();
    }
    return mCursor;
}

public boolean updateValues(long rowId, int number, String name, String version, String method, int chainNumber, boolean caught){
    ContentValues args = new ContentValues();
    args.put(KEY_NUMBER, number);
    args.put(KEY_NAME, name);
    args.put(KEY_VERSION, version);
    args.put(KEY_METHOD, method);
    args.put(KEY_CHAIN_NUMBER, chainNumber);
    args.put(KEY_CAUGHT, caught);

    return db.update(DATABASE_TABLE , args, KEY_ID + " = " + rowId, null) > 0;
}
}

关于如何实现这一点有什么建议吗？

Answer 1

假设您正在为数据库中的每个列使用 TextView，您可以在加载 ListView 的 Activity 中使用以下代码:

DBAdapter db = new DBAdapter(this);
Cursor cursor = db.getAllValues();

// The columns that you want to bind
String[] columns = new String[] {
    db.KEY_NUMBER,
    db.KEY_NAME,
    db.KEY_VERSION,
    db.KEY_METHOD,
    db.KEY_CHAIN_NUMBER,
    db.KEY_CAUGHT
};

// The IDs of the TextViews you want to bind the columns with
int[] to = new int[] { 
    R.id.number,
    R.id.name,
    R.id.version,
    R.id.method,
    R.id.chain_number,
    R.id.caught
};

// Attach the layout file and the columns to the ListView
SimpleCursorAdapter adapter = new SimpleCursorAdapter(
    this, 
    R.layout.your_listview_layout, 
    cursor, 
    columns, 
    to,
    0);

ListView listView = (ListView) findViewById(R.id.your_listview);
// Assign the adapter to the ListView
listView.setAdapter(dataAdapter);

确保您的 ListView 有一个布局文件。您可能需要更改此代码以满足您的需要。如果您有任何疑问，请在下方发表评论。