notifyDataSetChanged不起作用。 我收到短信时的ListView未更新

Question

首先，我是一个初学者，我尝试对此进行研究，尝试实施一些解决方案，但无法使其正常工作...

问题，

我想在收到短信，正在使用Receiver和notifydatasetChanged时即时更新活动。 一切似乎都正常（当我收到短信时，列表的大小会增加，它会通知适配器，但列表永远不会更新（如果我返回并再次打开活动，它将更新））

这是我的接收器的代码...

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();
    }
}}

这是我的活动代码。

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

您将NotifyDataSetChanged放在onCreate中（这就是为什么在创建活动时更新它的原因），您需要在refresh（）函数中调用此函数。

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

Answer 2

每当您要更新项目时，都不应重新创建适配器。 相反，您需要将项目交换到适配器。 您可以通过将适配器修改为如下形式来实现：

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);
}