Question

我想显示图片+电话号码。我已经为联系人创建了一个类：

public class Contact {

    private int CTC_ID;
    private byte[]  CTC_IMAGE;
    public String CTC_NOM;
    public String CTC_NUMERO;

    public Contact(){
    }

    public Contact(byte[] CTC_IMAGE, String CTC_NOM, String CTC_NUMERO){
        this.CTC_IMAGE = CTC_IMAGE;
        this.CTC_NOM = CTC_NOM;
        this.CTC_NUMERO = CTC_NUMERO;
    }
    public Contact(String CTC_NOM, String CTC_NUMERO){
        this.CTC_NOM = CTC_NOM;
        this.CTC_NUMERO = CTC_NUMERO;
    }



    public int getCTC_ID(){
        return CTC_ID;
    }
    public byte[] getCTC_IMAGE(){return CTC_IMAGE; }
    public String getCTC_NOM() {
        return CTC_NOM;
    }
    public String getCTC_NUMERO() {
        return CTC_NUMERO;
    }

    public void setCTC_ID(int CTC_ID) {
        this.CTC_ID = CTC_ID;
    }
    public void setCTC_IMAGE(byte[] CTC_IMAGE) { this.CTC_IMAGE = CTC_IMAGE;}
    public void setCTC_NOM(String CTC_NOM) { this.CTC_NOM = CTC_NOM;}
    public void setCTC_NUMERO(String CTC_NUMERO) {
        this.CTC_NUMERO = CTC_NUMERO;
    }


    public String toString(){
        return "ID : "+CTC_ID+"\nimage : "+CTC_IMAGE+"\nnom : "+CTC_NOM+"\nnumero : "+CTC_NUMERO;
    }
}

要将联系人添加到列表中，我在methode fetchAllContactDetail中有我的databaseHelper：

public ArrayList<Contact> fetchAllContactDetail() {
    SQLiteDatabase db = this.getWritableDatabase();
    ArrayList<Contact> contactListe = new ArrayList<>();

    Cursor mCursor = db.query(TABLE_CONTACT, new String[]{"CTC_ID _id", KEY_CTC_IMAGE, KEY_CTC_IMAGE, KEY_CTC_NOM, KEY_CTC_NUMERO}, null, null, null, null, null);

    if (mCursor.moveToFirst()) {
        do {
            byte[] image = mCursor.getBlob(mCursor.getColumnIndex(KEY_CTC_IMAGE));
            String name = mCursor.getString(mCursor.getColumnIndex(KEY_CTC_NOM));
            String numero = mCursor.getString(mCursor.getColumnIndex(KEY_CTC_NUMERO));
            contactListe.add(new Contact(image, name, numero));
        } while (mCursor.moveToNext());
    }
    return contactListe;
}

我创建了ContactAdapter extends BaseAdapter：

public class ContactAdapter extends BaseAdapter {

    private Context context;
    private ArrayList<Contact> contactList = new ArrayList<Contact>();


    // Constructor
    public ContactAdapter(Context context, ArrayList<Contact> contactList) {
        this.context = context;
        this.contactList.addAll(contactList);
    }
    @Override
    public int getCount() {
        return contactList.size();
    }

    @Override
    public Object getItem(int position) {
        return contactList.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    private class ViewHolder{
        ImageView img;
        TextView name;
    }

    @Override
    public View getView(int position, View view, ViewGroup viewGroup) {
        View row = view;
        ViewHolder holder = new ViewHolder();

        if(row == null){
            LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            row = inflater.inflate(R.layout.contact_item, null);
        }

        Contact contact = contactList.get(position);

        if (contactList != null) {
            holder.name = (TextView) row.findViewById(R.id.name);
            holder.img = (ImageView) row.findViewById(R.id.img);

            holder.name.setText(contact.getCTC_NUMERO());
            byte[] contactImage = contact.getCTC_IMAGE();
            Bitmap bitmap = BitmapFactory.decodeByteArray(contactImage, 0, contactImage.length);
            holder.img.setImageBitmap(bitmap);
            row.setTag(holder);
        }
        return row;

    }
}

我在mainActivity中将其返回：

public class MainActivity extends AppCompatActivity {
    private ListView lstViewContact;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
                setContentView(R.layout.activity_main);

                lstViewContact = (ListView) findViewById(R.id.lvContact);

                displayContact();

}

    public void displayContact() {

        //On ouvre la base de données pour écrire dedans
        DatabaseHelper dbHelper = new DatabaseHelper(this);
        final ContactAdapter contactAdapter = new ContactAdapter(this, dbHelper.fetchAllContactDetail());
        lstViewContact.setAdapter(contactAdapter);
    }
}

我的数据库有2个联系人，它通过contactListe返回

在我的ContactAdapter中

@Override
public int getCount() {
    return contactList.size();
}

返回2没关系。

我没有说出问题出在哪里。

谢谢你的帮助。

Answer 1

替换

ViewHolder holder = new ViewHolder();

if(row == null) {
    LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    row = inflater.inflate(R.layout.contact_item, null);
}

带

ViewHolder holder;

if(row == null) {
    LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    row = inflater.inflate(R.layout.contact_item, viewGroup, false);

    holder = new ViewHolder();
    // TODO: Initialise holder values, like
    // holder.name = row.findViewById(R.id.name);
    row.setTag(holder);
} else {
    holder = (ViewHolder) row.getTag();
}

Answer 2

您的问题出在您的getView（）实现

中

@Override
public View getView(int position, View view, ViewGroup viewGroup) {
    View row = view;
    ViewHolder holder = null;

    if(row == null){
        holder=new ViewHolder();
        LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        row = inflater.inflate(R.layout.contact_item, null);
        holder.name = (TextView) row.findViewById(R.id.name);
        holder.img = (ImageView) row.findViewById(R.id.img);
        row.setTag(holder);
    }else{
    holder=row.getTag();}

    Contact contact = contactList.get(position);

    if (contactList != null) {

        holder.name.setText(contact.getCTC_NUMERO());
        byte[] contactImage = contact.getCTC_IMAGE();
        Bitmap bitmap = BitmapFactory.decodeByteArray(contactImage, 0, contactImage.length);
        holder.img.setImageBitmap(bitmap);

    }
    return row;

}

这是关于持有人初始化问题。

粘贴上面的代码并尝试。

getView不返回数据

2 个答案: