通过使用Tab Android Studio（而非按钮）滑动视图将数据传递到另一个片段

刘玉石

2023-03-14

问题内容：

是否可以通过滑动将数据从一个片段传递到另一个片段？

有很多文章教我们如何将数据从一个片段传递到另一个片段，但是大多数文章或问题已在其第一个片段中实现了OnClickListener，该控件过去曾将值传递给另一个片段。

但是我的情况是不单击任何按钮就传递来自两个片段的数据，最后通过单击最后一个片段中的按钮将它们保存在不同的表中。我该怎么做？

流程为 Information>> WorkForce>> WorkDetailsTable，只需单击一下即可将它们保存到其他表中。

我试图解决它，但我在SQLite中得到NULL值。我想我错过了很多，但不知道。请帮助我…我被困在这里超过两天了…谢谢

Tab.java

public class Tab extends ActionBarActivity implements ActionBar.TabListener {
    ViewPager Tab;
    TabPagerAdapter TabAdapter;
    ActionBar actionBar;
    public static String name = null;
    public static String subContractors = null;

// will be used for data communication

    public static Force force_bean;;
    public static Info info_bean;


    public static Force getForce(){

        return force_bean;
    }
    public static void setForce(Force force){

        force_bean=force;
    }
    public static Info getInfo(){

        return info_bean;
    }
    public static void setInfo(Info info){

        info_bean=info;
    }



    final Activity mActivity = (Activity) this;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.tab1);


        info_bean = new Info();
        force_bean = new Force();


        TabAdapter = new TabPagerAdapter(getSupportFragmentManager());


        Tab = (ViewPager) findViewById(R.id.pager);

        Tab.setOnPageChangeListener(
                new ViewPager.SimpleOnPageChangeListener() {
                    @Override
                    public void onPageSelected(int position) {

                        actionBar = ((AppCompatActivity) mActivity).getSupportActionBar();
                        actionBar.setSelectedNavigationItem(position);
                    }
                });

        Tab.setAdapter(TabAdapter);

        actionBar = ((AppCompatActivity) mActivity).getSupportActionBar();

//Enable Tabs on Action Bar 
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);


//Add New Tabs 
        actionBar.addTab(actionBar.newTab().setText("Information").setTabListener(this));
        actionBar.addTab(actionBar.newTab().setText("Work Force").setTabListener(this));
        actionBar.addTab(actionBar.newTab().setText("Work Details").setTabListener(this));

    }


    @Override
    public void onTabSelected(ActionBar.Tab tab, android.support.v4.app.FragmentTransaction ft) {

    }

    @Override
    public void onTabUnselected(ActionBar.Tab tab, android.support.v4.app.FragmentTransaction ft) {

    }

    @Override
    public void onTabReselected(ActionBar.Tab tab, android.support.v4.app.FragmentTransaction ft) {

    }
}

TabPagerAdapter.java

public class TabPagerAdapter extends FragmentStatePagerAdapter {
        public TabPagerAdapter(FragmentManager fm) {
            super(fm);
        }
       @Override
        public Fragment getItem(int i) {
            switch (i) {
                case 0:
                    return  Information.newInstance("name");
                case 1:
                    return WorkForce.newInstance("SubCon");
                case 2:
                    return WorkDetailsTable.newInstance();
            }
            return null ;
        }
        @Override
        public int getCount() {
            return 3; //No of Tabs you can give your number of tabs
        }

信息库

public class Information extends Fragment implements View.OnClickListener {
        private Spinner spinner, spinner2, spinner3;

        private static String a;
         public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            View info = inflater.inflate(R.layout.information, container, false);
            dialog = new DateDialog();
            spinner = (Spinner)info.findViewById(R.id.spinner);
            addItemsOnSpinner();
            a= spinner.getSelectedItem().toString();
            return info;
        }

     public static Information newInstance(String a)
        {
           Information fragment=new Information();
            Bundle bundle=new Bundle();
            bundle.putString("a",a);
            fragment.setArguments(bundle);
            return fragment;
        }

     public void addItemsOnSpinner() {
            List<String> list = new ArrayList<String>();
            list.add("1 ");
            list.add("2");
            ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_spinner_dropdown_item, list);
            adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
            spinner.setAdapter(adapter);



        }

WorkForce.java

public class WorkForce extends Fragment {
        private static EditText txt1;
        private static String subCon;
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            View work = inflater.inflate(R.layout.workforce, container, false);
            txt1 = (EditText) work.findViewById(R.id.editText);
            subCon = txt1.getText().toString();
            return work;
        }

        public static WorkForce newInstance(String subCon) {

            WorkForce f = new WorkForce();
            Bundle bundle = new Bundle();
            bundle.putString("subCon", subCon);
            f.setArguments(bundle);
            return f;
        }
    }

WorkDetails.java

 private com.example.project.project.API.InfoAPI ts;
     private com.example.project.project.API.WorkDetailsAPI WD;
     private com.example.project.project.API.WorkForceAPI WF;
     public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     View workDetails = inflater.inflate(R.layout.tableworkdetails, container, false);
                getActivity().setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
        spinnerTra = (Spinner) workDetails.findViewById(R.id.spinner6);
        addItemsOnSpinner();
        Button btn1 = (Button)workDetails.findViewById(R.id.button2);
        WD = new com.example.project.project.API.WorkDetailsAPI(getActivity());
        ts = new com.example.project.project.API.InfoAPI(getActivity());
        WF = new com.example.project.project.API.WorkForceAPI(getActivity());
        a1 = spinnerTra.getSelectedItem().toString();
        Bundle bundle = new Bundle();
        final String name = bundle.getString("a");
        final String subContractors = bundle.getString("subCon");
        btn1.setOnClickListener(new View.OnClickListener() {
            public void onClick(View arg0) {



                 add(name, subContractors);
                }
            });

            return workDetails;
        }

     public void  add(String name,String subContractors)
        {
            Toast.makeText(getActivity(),+name+subContractors, Toast.LENGTH_SHORT).show();
ts.insertTimeSheet(name);
WF.insertWorkForce(subContractors);

        }

注意：我的情况是不单击任何按钮就传递两个片段中的数据，最后通过单击最后一个片段中的按钮将它们保存在不同的表中。

问题答案：

如果我正确理解了您的问题，则实际上是在执行一些类似“向导”的操作，其中，当您在各个标签之间滑动或选择时，每个步骤都会将信息传递给下一个步骤。

因此，实际上，您的问题是如何在取消选择片段时从片段中获取信息，并在选择片段时将其获取到片段中。

在最简单的级别上，我建议您的活动保存所有信息的“主”副本，并将其传递到选项卡寻呼机适配器中的每个片段中/从中获取。

您将需要某种“域”对象来保存您需要收集的所有信息。每个标签只会更新它关心的信息。

public class WorkData {
 string information;
 string subCon;
... etc..
}

您添加了一个实例来将主副本保存到“ tab”活动中：

public class Tab extends ActionBarActivity implements ActionBar.TabListener {
...
 WorkData workData = new WorkData();
...

然后，我建议您的每个“标签”片段都实现一个简单的接口；就像是：

public interface DataUpdate {
 void setData(WorkData data);
 WorkData getData();
}

每个选项卡片段都将实现此接口，并根据需要更新WorkData。

public class WorkForce extends Fragment implements DataUpdate {
...
  private WorkData workData; // this fragment's "copy" of the data
...
@Override
public WorkData getData() {
  this.workData.subCon = this.subCon; // Assuming subcon has been updated.. else use txt1.getText();
  return this.workData;
}

@Override
public void setData(WorkData workData) {
 this.workData = workData;
 // Update this page's views with the workData...
 // This assumes the fragment has already been created and txt1 is set to a view
 txt1.setText(workData.subCon);
 this.subCon = workData.subCon; // Actually could just use subCon in workData, but be aware that workData actually points to the Activity's copy (kinda makes getdata redundant.. but I like symmetry and couldn't be bothered making lots of copies of the object).
}

然后，您只需要添加代码即可在“ Tab”活动中向后和向前传递数据。

@Override
public void onTabSelected(ActionBar.Tab tab, android.support.v4.app.FragmentTransaction ft) {
 int position = tab.getPosition();
 DataUpdate dataUpdate = (DataUpdate) TabAdapter.getItem(position);
 // Pass the master workdata to the selected fragment
 dataUpdate.setData(this.workData);
}

@Override
public void onTabUnselected(ActionBar.Tab tab, android.support.v4.app.FragmentTransaction ft) {
 int position = tab.getPosition();
 DataUpdate dataUpdate = (DataUpdate) TabAdapter.getItem(position);
 // Update the master workdata from the unselected fragment
 this.workData = dataUpdate.getData();
}

@Override
public void onTabReselected(ActionBar.Tab tab, android.support.v4.app.FragmentTransaction ft) {
 // This might be pointless, but we'll do it anyway..
 int position = tab.getPosition();
 DataUpdate dataUpdate = (DataUpdate) TabAdapter.getItem(position);
 // Pass the master workdata to the selected fragment
 dataUpdate.setData(this.workData);
}

这里要注意的重要一点是，每次调用getItem（）时，TabPagerAdapter都会创建一个新的片段。这意味着我们将永远不会得到任何更新，因为每次尝试获取该片段时，它都会返回一个新的空片段。我们需要对此进行更改，以便在第一次请求时仍会创建片段，但只能创建一次，以便我们不会继续丢弃我们的工作。

public class TabPagerAdapter extends FragmentStatePagerAdapter {
 private static final int NUMBER_OF_TABS = 3;
 private Fragment[] tabList = new Fragment[NUMBER_OF_TABS];

        public TabPagerAdapter(FragmentManager fm) {
            super(fm);
        }
       @Override
        public Fragment getItem(int i) {
            if (tabList[i] != null) {
              // Return a tab we created earlier..
              return tabList[i];
            } else {
              switch (i) {
                  case 0:
                      tabList[0] = Information.newInstance("name");
                      return  tabList[0];
                  case 1:
                      tabList[1] = WorkForce.newInstance("SubCon");
                      return tabList[1];
                  case 2:
                      tabList[2] = WorkDetailsTable.newInstance();
                      return tabList[2];
              }
            }
            return null ;
        }
        @Override
        public int getCount() {
            return NUMBER_OF_TABS;
        }

希望这可以帮助。祝好运：-）

通过使用Tab Android Studio（而非按钮）滑动视图将数据传递到另一个片段

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