Android中的一個ListView中有兩個ArrayList

Question

請幫助我將兩個arraylist放在一個listview中。 我僅使用兩個listview顯示數據庫中的兩列。 我的編程能力不太好，所以我需要您的幫助。 提前致謝

這是我的主要活動

public class MainActivity extends Activity {
DataDB data = new DataDB();
ListView list;
ListView list2;
ArrayAdapter<String> listAdapter;

public MainActivity() {
}

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    list = (ListView) findViewById(R.id.listView);
    list2 = (ListView) findViewById(R.id.listView2);

    // set data

    ArrayList<String> firstName = new ArrayList<String>();
    try {
        firstName = data.getFNameDB(this);
    } catch (SQLException e) {
        e.printStackTrace();
    }

    listAdapter = new ArrayAdapter<String>(this, R.layout.support_simple_spinner_dropdown_item, firstName);

    // set the adapter
    list.setAdapter(listAdapter);


    ArrayList<String> lastName = new ArrayList<String>();
    try {
        lastName = data.getLNameDB(this);
    } catch (SQLException e) {
        e.printStackTrace();
    }

    listAdapter = new ArrayAdapter<String>(this, R.layout.support_simple_spinner_dropdown_item, lastName);

    // set the adapter
    list2.setAdapter(listAdapter);
}

這是我的數據庫

public class DataDB {
DatabaseHelper con;
ArrayList<String> firstName = new ArrayList<String>();
ArrayList<String> lastName = new ArrayList<String>();

public DataDB() {
}


public ArrayList<String> getFNameDB(Context context) throws SQLException {
    this.con = new DatabaseHelper(context);

    try {
        this.con.createDataBase();
    } catch (IOException e) {
        ;
    }

    if (!this.con.checkDataBase()) {
        return null;
    } else {
        this.con.openDataBase();
        SQLiteDatabase db = this.con.getWritableDatabase();

        for (Cursor cursor = db.rawQuery("SELECT firstName FROM tbl_doctor", (String[]) null); cursor.moveToNext(); this.firstName.add(cursor.getString(0))) {

        }


        this.con.close();
        return this.firstName;

    }

}

public ArrayList<String> getLNameDB(Context context) throws SQLException {
    this.con = new DatabaseHelper(context);

    try {
        this.con.createDataBase();
    } catch (IOException e) {
        ;
    }

    if (!this.con.checkDataBase()) {
        return null;
    } else {
        this.con.openDataBase();
        SQLiteDatabase db = this.con.getWritableDatabase();

        for (Cursor cursor = db.rawQuery("SELECT lastName FROM tbl_doctor", (String[]) null); cursor.moveToNext(); this.lastName.add(cursor.getString(0))) {

        }

        this.con.close();
        return this.lastName;

    }

}

Answer 1

更改您的代碼以在活動類中填充適配器，如下所示：

public class MainActivity extends Activity {
DataDB data = new DataDB();
ListView list;

ArrayAdapter<String> listAdapter;

public MainActivity() {
}

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    list = (ListView) findViewById(R.id.listView);

    ArrayList<String> finalList = new ArrayList<String>();
    // set data

    ArrayList<String> firstName = new ArrayList<String>();
    try {
        firstName = data.getFNameDB(this);
    } catch (SQLException e) {
        e.printStackTrace();
    }

    ArrayList<String> lastName = new ArrayList<String>();
    try {
        lastName = data.getLNameDB(this);
    } catch (SQLException e) {
        e.printStackTrace();
    }
    finalList.addAll(firstName);
    finalList.addAll(lastName);
    listAdapter = new ArrayAdapter<String>(this, R.layout.support_simple_spinner_dropdown_item, finalList);

    // set the adapter
    list.setAdapter(listAdapter);

}

Answer 2

只是為了清楚起見，您應該做的是使用單個ListView並在其中顯示firstName和lastName，為此我將演示一些代碼，還將添加一些必要的部分供您更好地理解事物，

在您訪問firstName的方法中，可以更新該方法以在單個查詢中同時獲取firstName和lastName ，如下所示->

public ArrayList<String> getNameDB(Context context) throws SQLException {
this.con = new DatabaseHelper(context);

try {
    this.con.createDataBase();
} catch (IOException e) {
    ;
}

if (!this.con.checkDataBase()) {
    return null;
} else {
    this.con.openDataBase();
    SQLiteDatabase db = this.con.getWritableDatabase();

    for (Cursor cursor = db.rawQuery("SELECT firstName,lastName FROM tbl_doctor", (String[]) null); cursor.moveToNext(); this.firstName.add(cursor.getString(0)+" "+cursor.getString(1)) {

    }


    this.con.close();
    return this.firstName;

}

}

現在，您可以按以下方式在適配器中使用此列表，

 ArrayList<String> names = new ArrayList<String>();
try {
    names = data.getNameDB(this);
} catch (SQLException e) {
    e.printStackTrace();
}



listAdapter = new ArrayAdapter<String>(this, R.layout.support_simple_spinner_dropdown_item, names);

// set the adapter
list.setAdapter(listAdapter);

詢問是否需要任何進一步的幫助。