notifyDataSetChanged不起作用。 我收到短信時的ListView未更新

Question

首先，我是一個初學者，我嘗試對此進行研究，嘗試實施一些解決方案，但無法使其正常工作...

問題，

我想在收到短信，正在使用Receiver和notifydatasetChanged時即時更新活動。 一切似乎都正常（當我收到短信時，列表的大小會增加，它會通知適配器，但列表永遠不會更新（如果我返回並再次打開活動，它將更新））

這是我的接收器的代碼...

public class SmsBroadcastReceiver extends BroadcastReceiver {

public SmsModel msg;
MessageListAdapter adapter;
ArraySms mSmsList;
public SmsListActivity inst;

public static final String SMS_BUNDLE = "pdus";


public void onReceive(Context context, Intent intent) {
    mSmsList = new ArraySms() {
    };
    mSmsList = PreferencesManager.getSmsList(context);
    Bundle intentExtras = intent.getExtras();
    if (intentExtras != null) {
        Object[] sms = (Object[]) intentExtras.get(SMS_BUNDLE);

        for (int i = 0; i < sms.length; i++) {
            String format = intentExtras.getString("format");
            SmsMessage smsMessage = null;
            if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.M) {
                smsMessage = SmsMessage.createFromPdu((byte[]) sms[i], format);
            }

            String smsBody = smsMessage.getMessageBody().toString();
            String address = smsMessage.getOriginatingAddress();
            msg = new SmsModel();
            msg.setNoticeText(smsBody);
            msg.setPhoneNumber(address);
            mSmsList.getSmsList().add(msg);
            }
           PreferencesManager.addSmsList(mSmsList,context);
        inst = SmsListActivity.instance();
        inst.updateList();
    }
}}

這是我的活動代碼。

public class SmsListActivity extends AppCompatActivity {

MessageListAdapter mSmsAdapter;
@BindView(R.id.recyclerview_sms_list)
RecyclerView mRecyclerView;
private static SmsListActivity inst;
ArraySms arraySms;
SmsModel smsModel;

public static SmsListActivity instance() {
    return inst;
}

@Override
public void onStart() {
    super.onStart();
    inst = this;
    mSmsAdapter.notifyDataSetChanged();
}

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_sms_list);
    ButterKnife.bind(this);
    mRecyclerView.setHasFixedSize(true);
    mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
    smsModel = new SmsModel();


    refreshSmsInbox();

    mSmsAdapter = new MessageListAdapter(this, arraySms);
    mRecyclerView.setAdapter(mSmsAdapter);
}

public ArraySms refreshSmsInbox() {
    arraySms = new ArraySms();
    arraySms.setSmsList(new ArrayList<>());
    ContentResolver contentResolver = getContentResolver();
    int permissionGranted = ContextCompat.checkSelfPermission(this, Manifest.permission.RECEIVE_SMS);
    if (permissionGranted == PackageManager.PERMISSION_GRANTED) {
        Cursor smsInboxCursor = contentResolver.query(Uri.parse("content://sms/inbox"), null, null, null, null);
        int indexBody = smsInboxCursor.getColumnIndex("body");
        int indexAddress = smsInboxCursor.getColumnIndex("address");
        while (smsInboxCursor != null && smsInboxCursor.moveToNext()) {
            smsModel = new SmsModel();
            smsModel.setPhoneNumber(smsInboxCursor.getString(indexAddress));
            smsModel.setNoticeText(smsInboxCursor.getString(indexBody));
            arraySms.getSmsList().add(smsModel);
        }
        if (smsInboxCursor != null) {
            smsInboxCursor.close();
        }

    }
    PreferencesManager.addSmsList(arraySms, SmsListActivity.this);
    return arraySms;


}
public void updateList() {
    arraySms = PreferencesManager.getSmsList(SmsListActivity.this);
    mSmsAdapter = new MessageListAdapter(SmsListActivity.this, arraySms);
    mRecyclerView.setAdapter(mSmsAdapter);
}

@Override
protected void onDestroy() {
    super.onDestroy();
}

}

Answer 1

您將NotifyDataSetChanged放在onCreate中（這就是為什么在創建活動時更新它的原因），您需要在refresh（）函數中調用此函數。

public void updateList() {
arraySms = PreferencesManager.getSmsList(SmsListActivity.this);
mSmsAdapter = new MessageListAdapter(SmsListActivity.this, arraySms);
mRecyclerView.setAdapter(mSmsAdapter);
mSmsAdapter.notifyDataSetChanged();
}

Answer 2

每當您要更新項目時，都不應重新創建適配器。 相反，您需要將項目交換到適配器。 您可以通過將適配器修改為如下形式來實現：

public class MessageListAdapter extends RecyclerView.Adapter<MessageListAdapter.ViewHolder> {

  public void swap(ArraySms arraySms) {
    // clearing the list
    ArrayList<> list = this.arraySms.getSmsList();
    list.clear()
    // then readd from arraySms
    list.addAll(arraySms.getSmsList());

    notifyDataSetChanged();
  }
}

然后可以在updateList方法中使用它：

public void updateList() {
    arraySms = PreferencesManager.getSmsList(SmsListActivity.this);
    mSmsAdapter.swap(arraySms);
}