Question

我正在尝试根据其“状态”用2个不同的数据组填充2个不同的ListView。我当前的代码运行没有错误，但我的ListViews没有得到填充。我有多个完整或不完整状态的测试数据。

Java代码：

public class view_to_do_task extends AppCompatActivity {
    private dbasemanager2 dBase2;
    private ListView taskList;
    private ListView taskList2;

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

        dBase2 = new dbasemanager2(this);
        dBase2.openReadable();
        taskList = (ListView)findViewById(R.id.incompleteTaskList);
        ArrayList<String> dBaseContent = dBase2.retrieveIncompleteRows();
        ArrayAdapter<String> arrayAdpt = new ArrayAdapter<>(this,
                android.R.layout.simple_list_item_1, dBaseContent);
        taskList.setAdapter(arrayAdpt);

        taskList2 = (ListView)findViewById(R.id.completeTaskList);
        dBaseContent = dBase2.retrieveCompleteRows();
        arrayAdpt = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, dBaseContent);
        taskList.setAdapter(arrayAdpt);

}

检索功能：

public ArrayList<String> retrieveIncompleteRows() {
    ArrayList<String> studentRows = new ArrayList<>();
    String[] columns = new String[] {"tid", "task", "status"};
    String s = "Incomplete";
    Cursor cursor = db.query(DB_TABLE, columns, "status=?", new String[] { s }, null, null, null);
    cursor.moveToFirst();
    while (!cursor.isAfterLast()) {
        studentRows.add(cursor.getString(0) + ". " + cursor.getString(1));
        cursor.moveToNext();
    }
    if (cursor != null && !cursor.isClosed()) {
        cursor.close();
    }
    return studentRows;
}

public ArrayList<String> retrieveCompleteRows() {
    ArrayList<String> studentRows = new ArrayList<>();
    String[] columns = new String[] {"tid", "task", "status"};
    String s = "Complete";
    Cursor cursor = db.query(DB_TABLE, columns, "status=?", new String[] { s }, null, null, null);
    cursor.moveToFirst();
    while (!cursor.isAfterLast()) {
        studentRows.add(cursor.getString(0) + ". " + cursor.getString(1));
        cursor.moveToNext();
    }
    if (cursor != null && !cursor.isClosed()) {
        cursor.close();
    }
    return studentRows;
}

Answer 1

为Adapters
创建单独的string list ListViews.

我在

下创建了单独的字符串列表和适配器

    ArrayList<String> dBaseContent = dBase2.retrieveIncompleteRows();
    ArrayAdapter<String> arrayAdpt = new ArrayAdapter<>(this,
            android.R.layout.simple_list_item_1, dBaseContent);
    taskList.setAdapter(arrayAdpt);

    ArrayList<String> dBaseContentComplete = dBase2.retrieveCompleteRows();
    ArrayAdapter<String> arrayAdptComplete = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, dBaseContentComplete);
    taskList2.setAdapter(arrayAdptComplete);

条件

public ArrayList<String> retrieveIncompleteRows() {

    ArrayList<String> studentRows = new ArrayList<>();
    String[] columns = new String[] {"tid", "task", "status"};
    String s = "Incomplete";

    //make changes here... and similarly while getting complete records other funtion.
    Cursor cursor = db.query(DB_TABLE, columns,
            "status = '"+ s + "'", null, null, null, null);

    cursor.moveToFirst();
    while (!cursor.isAfterLast()) {
        studentRows.add(cursor.getString(0) + ". " + cursor.getString(1));
        cursor.moveToNext();
    }
    if (cursor != null && !cursor.isClosed()) {
        cursor.close();
    }
    return studentRows;
}

Answer 2

为什么你不能用一个函数代替两个函数？

public ArrayList<String> retrieveCompleteRows(String s) {
    ArrayList<String> studentRows = new ArrayList<>();
    String[] columns = new String[] {"tid", "task", "status"};
    Cursor cursor = db.query(DB_TABLE, columns, "status=?", new String[] { s}, null, null, null);
 cursor.moveToFirst();
while (!cursor.isAfterLast()) {
    studentRows.add(cursor.getString(0) + ". " + cursor.getString(1));
    cursor.moveToNext();
}
if (cursor != null && !cursor.isClosed()) {
    cursor.close();
}
return studentRows;
}

你可以使用CursorLoader代替这个，因为它是异步的

Answer 3

试试这个

public ArrayList<String> retrieveIncompleteRows() {
    ArrayList<String> studentRows = new ArrayList<>();

    String s = "Incomplete";
    String selectQuery = "SELECT * FROM " + TABLE_NAME + " WHERE " + COLUMN_NAME + " = " + s + "";
    SQLiteDatabase db = this.getReadableDatabase();
    Cursor cursor = db.rawQuery(selectQuery, null);
    if (cursor.moveToFirst()) {
        do {
            studentRows.add(cursor.getString(0) + ". " + cursor.getString(1));

        } while (cursor.moveToNext());
    }
    return studentRows;
}

Android - 如何检索具有WHERE条件的数据库行？

3 个答案: