Question

我有一个具有ViewPager的主活动，在此ViewPager中我插入了两个片段：

public class MainActivity extends AppCompatActivity {

    private Toolbar toolbar;
    private TabLayout tabLayout;
    private ViewPager viewPager;

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

        toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        getSupportActionBar().setDisplayHomeAsUpEnabled(true);

        viewPager = (ViewPager) findViewById(R.id.viewpager);
        setupViewPager(viewPager);

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

    private void setupViewPager(ViewPager viewPager) {
        ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
        MyFrag f1 = new MyFrag();
        MyFrag f2 = new MyFrag();

        adapter.addFragment(f1, "F1");
        adapter.addFragment(f2, "F2");

        viewPager.setAdapter(adapter);
    }

    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);
        }
    }
}

然后在MyFrag中我想设置一个按钮点击监听器：

public class MyFrag extends Fragment{

    public void MyFrag(){

    }

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

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

        Button btn = (Button) container.findViewById(R.id.btn);    

        btn.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                addFragment(new MyOtherFrag());
            }
        });

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

    }

    public void addFragment(Fragment fragment){
        FragmentTransaction fragmentTransaction = getChildFragmentManager().beginTransaction();
        fragmentTransaction.add(R.id.fragContainer, fragment, "MyOtherFrag");
        fragmentTransaction.commit();
        getChildFragmentManager().executePendingTransactions();

    }

问题是Button btn = (Button) container.findViewById(R.id.btn);为空，因为容器是ViewPager而不是片段......我如何在这里得到我的片段？

Answer 1

要从MyFrag片段布局访问按钮，请使用从onCreateView方法返回的相同视图：

@Override
    public View onCreateView(...) {
        View view=inflater.inflate(R.layout.myfrag_fragment, container, false);
        Button btn = (Button) view.findViewById(R.id.btn);    
        ....

        return view;
    }

Answer 2

在片段的onCreateView中，更改为此

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             final Bundle savedInstanceState) {
    // Inflate the layout for this fragment
        View view = inflater.inflate(R.layout.myfrag_fragment, container, false);
        addFragment(new OtherFrag());

        Button btn = (Button) view.findViewById(R.id.btn);    

        btn.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                addFragment(new MyOtherFrag());
            }
        });

        return view;

    }

从ViewPager中的片段按钮获取id

2 个答案: