Question

我在1个活动中有4个片段（MainActivity：ViewPager）

fragment1 = edittext1，fragment2 = edittext2，fragment3 = edittext3＆amp; fragment4 = buttonsave

片段4中的

只有一个保存按钮，用于从片段1,2和3中检索数据但是当我单击buttonsave时，fragment1中的数据始终为null

MainActivity：

public class MainActivity extends AppCompatActivity {

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

    ViewPager viewPager = (ViewPager) findViewById(R.id.pager);
    ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
    adapter.addFragment(new FragmentOne(), "FRAG1");
    adapter.addFragment(new FragmentTwo(), "FRAG2");
    adapter.addFragment(new FragmentThree(), "FRAG3");
    adapter.addFragment(new FragmentFour(), "FRAG4");
    viewPager.setAdapter(adapter);

    TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
    tabLayout.setupWithViewPager(viewPager);
}

class ViewPagerAdapter extends FragmentPagerAdapter {
    private final List<Fragment> mFragmentList = new ArrayList<>();
    private final List<String> mFragmentTitleList = new ArrayList<>();

    public ViewPagerAdapter(FragmentManager manager) {
        super(manager);
    }

    @Override
    public Fragment getItem(int position) {
        return mFragmentList.get(position);
    }

    @Override
    public int getCount() {
        return mFragmentList.size();
    }

    public void addFragment(Fragment fragment, String title) {
        mFragmentList.add(fragment);
        mFragmentTitleList.add(title);
    }

    @Override
    public CharSequence getPageTitle(int position) {
        return mFragmentTitleList.get(position);
    }
}

片段1,2 dan 3

public class FragmentOne extends Fragment {
public FragmentOne() {
    // Required empty public constructor
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment

    return inflater.inflate(R.layout.fragment_one, container, false);
}

}

Fragment4

public class FragmentFour extends Fragment {

private EditText txt1, txt2, txt3;
private Button button;

public FragmentFour() {
    // Required empty public constructor
}

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

    txt1 = (EditText)getActivity().findViewById(R.id.txt1);
    txt2 = (EditText)getActivity().findViewById(R.id.txt2);
    txt3 = (EditText)getActivity().findViewById(R.id.txt3);

    button = (Button)view.findViewById(R.id.button);
    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            getData();
        }
    });
    return view;
}

private void getData() {
    String fragment1 = txt1.getText().toString();
    String fragment2 = txt2.getText().toString();
    String fragment3 = txt3.getText().toString();
}

空问题

text1（片段）中的数据始终为null：

Data from text1 (fragment)always null

我该怎么做才能解决这个问题？

非常感谢...

Answer 1

您必须使用共享首选项来存储FragmentOne数据，FragmentTwo数据，然后在保存按钮上检索到FragmentTree

Answer 2

您可以使用参数在片段之间传递数据，例如

$("#free").val("y").change();

并检索所需片段中的数据

Bundle bundle = new Bundle();
bundle.putString("someEditTextData",someEditTextData);
SomeFragment fragment = new SomeFragment ();
fragment.setArguments(bundle);

Answer 3

您可以为此目的使用共享偏好

创建SharedPreferences

SharedPreferences pref = getApplicationContext().getSharedPreferences("DATA", MODE_PRIVATE); 
Editor editor = pref.edit();
editor.putString("EDITEXT1", "string value");  // Saving string data of your editext
editor.commit(); // commit and save your data in to SharedPreferences

现在检索您的数据，如下面的代码

SharedPreferences pref = getApplicationContext().getSharedPreferences("DATA", MODE_PRIVATE); 
String email=pref.getString("EDITEXT1", "");       // Saving string data of your editext

Answer 4

您可以在活动中定义一个实例字段，并可以通过向片段中的MainActivity引用getActivity（）引用来访问它。

((MainActivity) getActivity()).filedName.setFragmentOneData(data);

Answer 5

如果你想访问Fragment 1 editText数据，那么viewPager总是加载两面连续的1页，然后添加这一行

 viewPager.setOffscreenPageLimit(4);

或使用静态变量

如何使用viewpager从输入数据片段获取值

5 个答案: