我如何使用interface.b共享数据黑白片段，我想在片段2的文本视图中单击打开按钮单击片段1中的编辑文本数据

Question

Main class is

public class MainActivity extends AppCompatActivity implements TabLayout.OnTabSelectedListener, MyInterface {

    ViewPager vp;
    TabLayout tabLayout;

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

        vp = (ViewPager) findViewById(R.id.mViewpager_ID);
        this.addPages();
        tabLayout = (TabLayout) findViewById(R.id.mTab_ID);
        tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
        tabLayout.setupWithViewPager(vp);
        tabLayout.setOnTabSelectedListener(this);
    }

    private void addPages() {
        MyPagerAdapter pagerAdapter = new MyPagerAdapter(this.getSupportFragmentManager());
        pagerAdapter.addFragment(new Fragment1());
        pagerAdapter.addFragment(new Fragment2());
        pagerAdapter.addFragment(new Fragment3());
        vp.setAdapter(pagerAdapter);
    }

    public void onTabSelected(TabLayout.Tab tab) {
        vp.setCurrentItem(tab.getPosition());
    }
    @Override
    public void onTabUnselected(TabLayout.Tab tab) {
    }

    @Override
    public void onTabReselected(TabLayout.Tab tab) {
    }
    @Override
    public String setOnDataChangedListener(String Text) {
    return Text;
    }
    @Override
    public void onFragmentChanged(int value) {
        if (value == 0) {
            vp.setCurrentItem(value);
            }
            if (value == 1) {
            vp.setCurrentItem(value);
             }
          if (value == 2) {
            vp.setCurrentItem(value);
        }
    }}

Fragment1 is:

public class Fragment1 extends Fragment {
    private MyInterface obj;
    String a;
    Context c;
    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        obj = (MyInterface) context;
          }
        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View rootView=inflater.inflate(R.layout.activity_fragment1,container,false);
        EditText edttext=(EditText)rootView.findViewById(R.id.edttxt);
        final String data=edttext.getText().toString();
        a="testing_communication";
        Button btn=(Button)rootView.findViewById(R.id.button);
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                obj.setOnDataChangedListener(data);
                obj.onFragmentChanged(1);
             } 
           });
        return rootView;
    }
    @Override
    public String toString() {
        String title="Fragment:1";
        return title;}}

Fragment2 is..

public class Fragment2 extends Fragment implements MyInterface {
@Nullable

TextView tv;
String text;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View bootView2=inflater.inflate(R.layout.activity_fragment2,container,false);
    tv = (TextView) bootView2.findViewById(R.id.textv);
    setOnDataChangedListener(text);
    tv.setText(text);
    return bootView2;

}

@Override
public String toString() {
    String title="Fragment:2";
    return title;
}

@Override
public String setOnDataChangedListener(String Text) {
return Text;
}
@Override
public void onFragmentChanged(int value) {
 }
 }

Interface is:

public interface MyInterface {
String setOnDataChangedListener(String Text);
void onFragmentChanged(int value);}

Pageadabter is:

public class MyPagerAdapter extends FragmentPagerAdapter {
ArrayList<Fragment> fragments=new ArrayList<>();
public MyPagerAdapter(FragmentManager fm) {
    super(fm);
}
@Override
public Fragment getItem(int position) {
    return fragments.get(position);
}
@Override
public int getCount() {
    return fragments.size();
}
public void addFragment(Fragment f)
{
    fragments.add(f);
}
@Override
public CharSequence getPageTitle(int position) {
    String title=fragments.get(position).toString();
    return title.toString();
}}

On button click fragment1, I am able to move at fragment2 but I am not able to move with the data.it seems in fragment1 under onclicklistener body obj.onFragmentChanged(1); is working fine.but obj.setOnDataChangedListener(data.); is not working.. If anybody can help, I will be very thankful to you.

Answer 1

Many problems here. The two that are causing this problem are mainly

First, in Fragment1 you're casting context as MyInterface and using that to set the data. Context on that case would be the activity containing Fragment1, not Fragment2

Second, your setDataChangedListener does basically nothing. It recieves a String and then returns the same thing without ever storing it anywhere.

You need Fragment2 to implement setDataChangedListener, recieve a String and then stores it in a class variable.

Answer 2

Do you really want to share data using interface? You can share data using Bundle , or using a public field of MainActivity .

Answer 3

https://www.journaldev.com/14207/android-passing-data-between-fragments#comment-45206帮助我解决了问题。