Question

使用TabLayout时，我很难将数据从一个片段发送到另一个片段。我已经阅读了大量有关如何执行此操作的在线帖子，并且在自己实施这些帖子时没有成功。

我在应用程序中设置了四个片段。我正在尝试将从第四个片段的EditText元素收集的数据发送到第二个片段的TextView元素。

我没有收到任何错误，但是文本没有出现在第二个片段中。我不知道如何从这里继续。谢谢！

第四片段（发送片段）

public class settings extends Fragment {
    SendMessage SM;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View rootView = inflater.inflate(
                R.layout.setl, container, false);
        return rootView;


    }

    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        Button btnPassData = (Button) view.findViewById(R.id.btnPassData);
        final EditText inData = (EditText) view.findViewById(R.id.inMessage);
        btnPassData.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                SM.sendData(inData.getText().toString().trim());
            }
        });

    }

    public interface SendMessage {
        void sendData(String message);
    }

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);

        try {
            SM = (SendMessage) getActivity();
        } catch (ClassCastException e) {
            throw new ClassCastException("Error in retrieving data. Please try again");
        }
    }
}

第二个片段（接收片段）

public class tt extends Fragment {

    TextView txtData;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View rootView = inflater.inflate(
                R.layout.ttl, container, false);

        return rootView;



    }

    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        txtData = (TextView)view.findViewById(R.id.txtData);


    }

    public void displayReceivedData(String message) {
        txtData.setText("Data received: "+ message);

    }
}

主要活动

public class MainActivity extends AppCompatActivity implements settings.SendMessage {

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        getWindow().setFlags(WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS, WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS);
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_test);
        SectionsPagerAdapter sectionsPagerAdapter = new SectionsPagerAdapter(this, getSupportFragmentManager());
        ViewPager viewPager = findViewById(R.id.view_pager);
        viewPager.setAdapter(sectionsPagerAdapter);
        TabLayout tabs = findViewById(R.id.tabs);
        tabs.setupWithViewPager(viewPager);
    }

    @Override
    public void sendData(String message) {
        String tag = "android:switcher:" + R.id.view_pager + ":" + 1;
        tt f = (tt) getSupportFragmentManager().findFragmentByTag(tag);
        f.displayReceivedData(message);
    }
}

Answer 1

您的应用程序其他部分可能出现故障。

下面是您的工作示例代码。

MainActivity类

const express = require('express');
const bodyParser = require('body-parser')
const path = require('path');
const cors = require('cors');
const app = express();

app.use(express.static(path.join(__dirname, 'build')));
app.use(express.urlencoded({ extended: true }));
app.use(express.json());
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));

app.use((req, res, next) => {
    res.header('Access-Control-Allow-Origin', "*");
    res.header('Access-Control-Allow-Methods', "GET,PUT,POST,DELETE");
    res.header('Access-Control-Allow-Methods', "Content-Type");
    next();
});

app.get('/*',function (req, res) {
    res.sendFile(path.join(__dirname, 'build/index.html'), function (err) {
        if (err) {
            res.status(500).send(err)
        }
    })
})

app.get('/', cors(), function (req, res) {
    res.sendFile(path.join(__dirname, 'build', 'index.html'));
});

app.listen(5000);


console.log('App is listening on port 5000');

课程设置

public class MainActivity extends AppCompatActivity implements Setting.SendMessage {

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        getWindow().setFlags(WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS, WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS);
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        SectionsPagerAdapter sectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager(),this );
        ViewPager viewPager = findViewById(R.id.viewpager);
        viewPager.setAdapter(sectionsPagerAdapter);
        TabLayout tabs = findViewById(R.id.sliding_tabs);
        tabs.setupWithViewPager(viewPager);
    }

    @Override
    public void sendData(String message) {
        String tag = "android:switcher:" + R.id.viewpager + ":" + 1;
        tt f = (tt) getSupportFragmentManager().findFragmentByTag(tag);
        f.displayReceivedData(message);
    }
}

tt类

 public class Setting extends Fragment {
        SendMessage SM;
        @Nullable
        @Override
        public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
            View rootView = inflater.inflate(
                    R.layout.setl, container, false);
            return rootView;
        }

        @Override
        public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
            super.onViewCreated(view, savedInstanceState);

            Button btnPassData = (Button) view.findViewById(R.id.btnPassData);
            final EditText inData = (EditText) view.findViewById(R.id.inMessage);
            btnPassData.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    SM.sendData(inData.getText().toString().trim());
                }
            });

        }
        public interface SendMessage {
            void sendData(String message);
        }

        @Override
        public void onAttach(Context context) {
            super.onAttach(context);
            try {
                SM = (SendMessage) getActivity();
            } catch (ClassCastException e) {
                throw new ClassCastException("Error in retrieving data. Please try again");
            }
        }
    }

SectionsPagerAdapter类

public class tt extends Fragment {

    TextView txtData;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View rootView = inflater.inflate(
                R.layout.tt, container, false);
        return rootView;
    }

    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        txtData = (TextView)view.findViewById(R.id.txtData);
    }

    public void displayReceivedData(String message) {
        txtData.setText("Data received: "+ message);

    }
}

使用TabLayout在片段之间发送数据

1 个答案: