所以我有一个ListView和一个自定义适配器 我正在为数据库添加值，然后重新填充列表 所以我按以下方式添加项目：q，w，e，r，t，y，u，i，o，p listview填充如下：q，w，e，r，t，y，q，q，q
这是自定义适配器
public class TestListAdapter extends BaseAdapter {
private static ArrayList<FlashCard> flashCardItems;
private LayoutInflater mInflater;
private Context context;
public TestListAdapter(Context context, ArrayList<FlashCard> results) {
this.context = context;
flashCardItems = results;
mInflater = LayoutInflater.from(context);
}
public int getCount() {
return flashCardItems.size();
}
public Object getItem(int position) {
return flashCardItems.get(position);
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
convertView = mInflater.inflate(R.layout.flashcard, null);
holder = new ViewHolder();
holder.flipper = (ViewFlipper) convertView.findViewById(R.id.flashcard);
convertView.setTag(holder);
}
else {
holder = (ViewHolder) convertView.getTag();
}
holder.flipper.addView(FlashCard.createQuestionCard(context,flashCardItems.get(position).getQuestion()));
return convertView;
}
static class ViewHolder {
ViewFlipper flipper;
}
}
这是数据库处理程序
public class DatabaseHandler extends SQLiteOpenHelper {
// All Static variables
// Database Version
private static final int DATABASE_VERSION = 1;
// Database Name
private static final String DATABASE_NAME = "mySchoolDB";
// Flashcards table name
private static final String TABLE_FLASHCARDS = "flashcards";
// Flashcards Table Columns names
private static final String KEY_ID = "id";
private static final String QUESTION = "question";
private static final String ANSWER = "answer";
public DatabaseHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
// Creating Tables
@Override
public void onCreate(SQLiteDatabase db) {
String CREATE_FLASHCARDS_TABLE = "CREATE TABLE " + TABLE_FLASHCARDS + "("
+ KEY_ID + " INTEGER PRIMARY KEY," + QUESTION + " TEXT,"
+ ANSWER + " TEXT" + ")";
db.execSQL(CREATE_FLASHCARDS_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_FLASHCARDS);
// Create tables again
onCreate(db);
}
/**
* All CRUD(Create, Read, Update, Delete) Operations
*/
// Adding new Flashcard
public void addFlashcard(FlashCard flashcard) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(QUESTION, flashcard.getQuestion()); // flashcard Name
values.put(ANSWER, flashcard.getAnswer()); // flashcard Phone
// Inserting Row
db.insert(TABLE_FLASHCARDS, null, values);
db.close(); // Closing database connection
}
// Getting single FlashCard
public FlashCard getFlashcard(int id) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(TABLE_FLASHCARDS, new String[] { KEY_ID,
QUESTION, ANSWER }, KEY_ID + "=?",
new String[] { String.valueOf(id) }, null, null, null, null);
if (cursor != null)
cursor.moveToFirst();
FlashCard flashcard= new FlashCard(Integer.parseInt(cursor.getString(0)),
cursor.getString(1), cursor.getString(2));
cursor.close();
db.close();
// return FlashCard
return flashcard;
}
// Getting All Flashcards
public ArrayList<FlashCard> getAllFlashcards() {
ArrayList<FlashCard> FlashcardList = new ArrayList<FlashCard>();
// Select All Query
String selectQuery = "SELECT * FROM " + TABLE_FLASHCARDS;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
FlashCard flashcard = new FlashCard(Integer.parseInt(cursor.getString(0)),cursor.getString(1),cursor.getString(2));
// Adding Flashcard to list
FlashcardList.add(flashcard);
} while (cursor.moveToNext());
}
cursor.close();
db.close();
// return Flashcard list
return FlashcardList;
}
// Updating single Flashcard
public int updateFlashcard(FlashCard flashcard) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(QUESTION, flashcard.getQuestion());
values.put(ANSWER, flashcard.getAnswer());
db.close();
// updating row
return db.update(TABLE_FLASHCARDS, values, KEY_ID + " = ?",
new String[] { String.valueOf(flashcard.getID()) });
}
// Deleting single Flashcard
public void deleteFlashcard(FlashCard flashcard) {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLE_FLASHCARDS, KEY_ID + " = ?",
new String[] { String.valueOf(flashcard.getID()) });
db.close();
}
// Getting Flashcards Count
public int getFlashcardsCount() {
String countQuery = "SELECT * FROM " + TABLE_FLASHCARDS;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
cursor.close();
// return count
return cursor.getCount();
}
public void deleteAllFlashCards(){
SQLiteDatabase sdb= this.getWritableDatabase();
sdb.delete(TABLE_FLASHCARDS, null, null);
sdb.close();
}
}
这是listview
public class TestList extends ListView
{
private Context context;
private ArrayList<FlashCard> stringArray = new ArrayList<FlashCard>();
public TestList(Context context) {
super(context);
this.context = context;
setResults();
}
public void setResults() {
DatabaseHandler db = new DatabaseHandler(context);
stringArray = db.getAllFlashcards();
setAdapter(new TestListAdapter(context, stringArray));
}
public TestList(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
public void addFlashCardDialog() {
final AlertDialog.Builder builder = new AlertDialog.Builder(context);
builder.setTitle("Add flashcard");
final EditText question = new EditText(context);
question.setHint("Question");
final EditText answer = new EditText(context);
answer.setHint("Answer");
LinearLayout qa = new LinearLayout(context);
qa.setOrientation(LinearLayout.VERTICAL);
qa.addView(question);
qa.addView(answer);
builder.setView(qa);
builder.setPositiveButton("Add", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
FlashCard f = new FlashCard(question.getText().toString(), answer.getText().toString());
DatabaseHandler db = new DatabaseHandler(context);
db.addFlashcard(f);
setResults();
}
});
builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
}
});
builder.show();
}
}
答案 0 :(得分：0)
addView()未替换当前存在的视图。当convertView重新回收时，{q}已存在于ViewFlipper内，您希望q消失并被'u'替换
holder.flipper.addView(FlashCard.createQuestionCard(context,flashCardItems.get(position).getQuestion()));
尝试将视图翻转器内的视图设置为新值，而不是使用addView（）。
示例：
TextView text = (TextView) ViewFlipper.findViewById(R.id.textView);
text.setText(flashCardItems.get(position).getQuestion());
答案 1 :(得分：0)
问题来自您在适配器中使用的ViewFlipper。
在android使用视图回收中列出视图（这是convertView在getView中的用途），但是由于每次视图被回收时你都在处理它们，你需要向翻译器添加另一个视图，你需要做的是当convertView为null时添加视图，然后修改翻转器中的视图以表示您的数据，不确定问题卡视图的工作方式，所以我只是猜测那里。
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
convertView = mInflater.inflate(R.layout.flashcard, null);
holder = new ViewHolder();
holder.flipper = (ViewFlipper) convertView.findViewById(R.id.flashcard);
holder.card = FlashCard.createQuestionCard(context,flashCardItems.get(position).getQuestion());
holder.filpper.addView(holder.card);
convertView.setTag(holder);
}
else {
holder = (ViewHolder) convertView.getTag();
}
holder.card.setQuestion(flashCardItems.get(position).getQuestion());
return convertView;
}
显然你必须调整你的视图持有者并添加一个具有正确类型的卡片字段，并在questionCard视图中添加一个setQuestion方法，但你明白了。