Question

我有一个数据库，我可以在其中创建和删除新记录。我希望此记录显示在另一个活动的列表视图中。

数据库：

public class DBHelper extends SQLiteOpenHelper {
// Database Version
private static final int DATABASE_VERSION = 1;

// Database Name
private static final String DATABASE_NAME = "spinnerExample";

// Labels table name
private static final String TABLE_LABELS = "labels";

// Labels Table Columns names
private static final String KEY_ID = "id";
private static final String KEY_NAME = "name";

public DBHelper(Context context) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
}

// Creating Tables
@Override
public void onCreate(SQLiteDatabase db) {
    // Category table create query
    String CREATE_CATEGORIES_TABLE = "CREATE TABLE " + TABLE_LABELS + "("
            + KEY_ID + " INTEGER PRIMARY KEY," + KEY_NAME + " TEXT)";
    db.execSQL(CREATE_CATEGORIES_TABLE);
}

// Upgrading database
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    // Drop older table if existed
    db.execSQL("DROP TABLE IF EXISTS " + TABLE_LABELS);

    // Create tables again
    onCreate(db);
}

/**
 * Inserting new lable into lables table
 * */
public void insertLabel(String label){
    SQLiteDatabase db = this.getWritableDatabase();

    ContentValues values = new ContentValues();
    values.put(KEY_NAME, label);

    // Inserting Row
    db.insert(TABLE_LABELS, null, values);
    db.close(); // Closing database connection
}

/**
* Removing label
* */
public void removeLabel(String label){
SQLiteDatabase db = this.getWritableDatabase();

ContentValues values = new ContentValues();
values.put(KEY_NAME, label);

// Removing Row
db.delete(TABLE_LABELS, KEY_NAME + "=?", new String[] {label});
db.close(); // Closing database connection
}

/**
 * Getting all labels
 * returns list of labels
 * */
public List<String> getAllLabels(){
    List<String> labels = new ArrayList<String>();

    // Select All Query
    String selectQuery = "SELECT  * FROM " + TABLE_LABELS;

    SQLiteDatabase db = this.getReadableDatabase();
    Cursor cursor = db.rawQuery(selectQuery, null);

    // looping through all rows and adding to list
    if (cursor.moveToFirst()) {
        do {
            labels.add(cursor.getString(1));
        } while (cursor.moveToNext());
    }

    // closing connection
    cursor.close();
    db.close();

    // returning lables
    return labels;
}
}

列表视图的布局：

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Modules"
    android:layout_margin="10dp" 
    android:textStyle="bold"
    android:textSize="30dp"
    android:layout_gravity="center"/>

<ListView
    android:id="@+id/lst_module"
    android:layout_width="match_parent"
    android:layout_height="330dp" 
    android:layout_marginRight="7dp"
    android:layout_marginLeft="7dp"
    android:layout_marginTop="7dp" >
</ListView>

<Button
    android:id="@+id/btn_edtmodule"
    android:layout_width="fill_parent"
    android:layout_height="64dp"
    android:text="Edit Modules" 
    android:textStyle="bold"
    android:layout_marginLeft="10dp"
    android:layout_marginRight="10dp"/>

 </LinearLayout>

活动类：

  public class Module extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.module);

    Button editModule = (Button) findViewById(R.id.btn_edtmodule);
    editModule.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View arg0) {
            // TODO Auto-generated method stub
            startActivity(new Intent("sg.edu.tp.iit.mns.VotingAppMain"));           
        }
    });        
}

我想知道活动类的代码是什么..有人可以帮助我。我是这个Android世界的新手。

Answer 1

为了在列表视图中显示所有项目，首先创建自定义listView并从数据库中获取数据并存储在ArrayList中

Class Data{
    String name,Address;
}

ArrayList<Data>list=new ArrayList<Data>();

Cursor userListCursor = dbAdapter.fetchAllRecord();
startManagingCursor(userListCursor);

while (!userListCursor.isAfterLast()) {
    Data record=new Data();
    record.name=userListCursor.getString(0);
    record.address=userListCursor.getString(1);
    list.add(record);
    userListCursor.moveToNext();
}

将此arraylist发送给扩展 BaseAdapter课程的班级并在getView()方法下设置这些值。

Answer 2

假设您只需要在ListView中显示数据库的内容，那么请查看以下问题：

https://stackoverflow.com/questions/11516340/how-to-on-refreshing-android-listfragment-listview-after-modifying-its-contents

那里的代码确实如此，应该指向正确的方向。如果你在onItemClick之后删除一个项目，那么你可能会遇到麻烦。

从sqlite数据库创建listview

2 个答案: