Question

我想重写公共函数getItem（int position）：

public class SectionsPagerAdapter extends FragmentPagerAdapter {

        public SectionsPagerAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int position) {
            switch (position) {
                case 0:
                    Tab1Content tab1 = new Tab1Content();
                    return tab1;
                case 1:
                    Tab2Content tab2 = new Tab2Content();
                    return tab2;
                case 2:
                    Tab3Content tab3 = new Tab3Content();
                    return tab3;
            }
            return null;
        }
}

Tab1Content看起来像这样：

public class Tab1Content extends Fragment {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.tab1_content, container, false);
        return rootView;
    }
}

但Android Studio会在日志中引发错误：

Error:(141, 28) error: incompatible types: Tab1Content cannot be converted to Fragment

我做错了什么？

Answer 1

Your fragment should be extending the android.support.v4.Fragment.

And apart from that, you should use an Empty Constructor in your fragment.

You can also use newInstance method if you want to pass some data in your fragment:

In Fragment:

   public static TestFragment newInstance(int type) {

        TestFragment f = new TestFragment();
        Bundle b = new Bundle();
        b.putInt("type", type);

        f.setArguments(b);

        return f;
    }

Your getItem would look like this:

@Override public Fragment getItem(int position) {
        switch (position) {
            case 0:
                return TestFragment.newInstance(1);
            case 1:
                return TestFragment1.newInstance(2);
            case 2:
                return TestFragment2.newInstance(3);
        }
        return null;
    }

TestFragment1 and TestFragment2 is similar to your TestFragment.

包含碎片的返回类

1 个答案: