我有一個(gè)工作 AsyncTask 從服務(wù)器獲取數(shù)據(jù)并將其顯示在 TextView 中。但是是否可以將數(shù)據(jù)輸出到位于片段中的 TextView 中？因此，假設(shè) AsyncTask 在 MainActivity 中加載，輸出將在一個(gè)片段中。這是我的異步任務(wù)： private static class FtpDownload extends AsyncTask<String, String, String> { private WeakReference<GuidanceActivity> activityWeakReference; FtpDownload(GuidanceActivity activity) { activityWeakReference = new WeakReference<>(activity); } @Override protected void onPreExecute() { super.onPreExecute(); } @Override protected String doInBackground(String... FTPconnection) { GuidanceActivity activity = activityWeakReference.get(); if (activity == null || activity.isFinishing()) { return null; } try { FTPClient ftpClient = new FTPClient(); ftpClient.connect("", 21); System.out.println(ftpClient.getReplyString()); ftpClient.enterLocalPassiveMode(); ftpClient.login("anonymous", ""); ftpClient.changeWorkingDirectory("/"); InputStream inStream = ftpClient.retrieveFileStream(".html"); activity.contents = IOUtils.toString(inStream, StandardCharsets.UTF_8); System.out.println(activity.contents); ftpClient.disconnect(); } catch (IOException e) { e.printStackTrace(); } return null; } @Override protected void onPostExecute(String output) { GuidanceActivity activity = activityWeakReference.get(); if (activity == null || activity.isFinishing()) { return; } TextView textView = activity.findViewById(R.id.text_view); textView.setText(Html.fromHtml(activity.contents)); } }
2 回答
莫回?zé)o
TA貢獻(xiàn)1865條經(jīng)驗(yàn) 獲得超7個(gè)贊
在您的片段中：
public class MyFragment extends Fragment {
TextView myTextView;
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
super.onCreateView(inflater, container, savedInstanceState);
View view = View root = inflater.inflate(R.layout.my_frag_layout, null);
myTextView = (TextView) view.findViewById(R.id.myTextView);
//rest of your implementation of onCreateView
return view;
}
//this will be called from activity
public void updateTextView(String text) {
myTextView.setText(text);
}
}
在您的活動(dòng)中：
public class MyActivity extends AppCompatActivity {
private final String FRAGMENT_TAG = "myFragment";
private static class FtpDownload extends AsyncTask<String, String, String> {
//rest of your FtpDownload class
@Override
protected void onPostExecute(String output) {
GuidanceActivity activity = activityWeakReference.get();
if (activity == null || activity.isFinishing()) {
return;
}
MyFragment fragment = (MyFragment) getSupportFragmentManager().findFragmentByTag(FRAGMENT_TAG );
/* or
MyFragment fragment = (MyFragment) getSupportFragmentManager().findFragmentById(R.id.fragment );
if your fragment is in an xml layout */
fragment.updateTextView(Html.fromHtml(activity.contents));
}
}
}
縹緲止盈
TA貢獻(xiàn)2041條經(jīng)驗(yàn) 獲得超4個(gè)贊
對(duì)的，這是可能的。這是來自 MainActivity 的 WiFi 掃描示例，結(jié)果顯示在片段中。我相信您可以理解邏輯并將其轉(zhuǎn)換為您的項(xiàng)目
主要活動(dòng)：
public class MainActivity extends AppCompatActivity implements FragmentDiscoverWiFi.ScanWiFi;
//public variable
FragmentDiscoverWiFi fragmentDiscoverWiFi;
//This will be called from your fragment
@Override
public void onScanWiFi(FragmentDiscoverWiFi fragment) {
fragmentDiscoverWiFi = fragment;
}
//use something like this when your want to update fragment
fragmentDiscoverWiFi.onScanWiFiComplete();
分段：
public class FragmentDiscoverWiFi extends Fragment {
private Context mContext;
public interface ScanWiFi {
public void onScanWiFi(FragmentDiscoverWiFi fragment);
}
public FragmentDiscoverWiFi() {
// Required empty public constructor
}
@Override
public void onAttach(Context context) {
mContext = context;
super.onAttach(context);
}
public void onScanWiFiComplete() {
if (!isDetached()) {
//Access your data from MainActivity like this:
Log.d(TAG, "Total APs:" + ((MainActivity) mContext).wifiScanResults.size());
}
}
@Override
public void onResume() {
super.onResume();
if (!getUserVisibleHint()) {
return;
}
pullToRefreshText = rootView.findViewById(R.id.pullToRefreshText);
pullToRefresh = rootView.findViewById(R.id.pullToRefresh);
pullToRefresh.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
Log.d(TAG, "refreshing...");
pullToRefresh.setRefreshing(true);
((MainActivity)mContext).onScanWiFi(FragmentDiscoverWiFi.this);
}
});
}
}
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