Android——导航栏，Fragment，FragmentPaperAdapter，ViewPaper

介绍

　　Android的导航栏是由Fragment，FragmentPagerAdapter，ViewPaper组成。

 

使用

　　1. 建立Layout资源文件，构造成Fragment

　　2. 重写FragmentPagerAdapter返回对应标号的Fragment

　　3. Viewpager进行适配

 

vp = findViewById(R.id.vp);
myFragmentAdapter = new MyFragmentAdapter(getSupportFragmentManager());
vp.setAdapter(myFragmentAdapter);

 

 

Fragment代码　　

public class Fragment1 extends Fragment {

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View item = inflater.inflate(R.layout.vp1, container, false);

        return item;
    }
}

 

FragmentPagerAdapter代码

public class MyFragmentAdapter extends FragmentPagerAdapter {
    public MyFragmentAdapter(@NonNull FragmentManager fm) {
        super(fm);
    }

    @NonNull
    @Override
    public Fragment getItem(int position) {
        switch ( position ){
            case 0:
                return new Fragment1();
            case 1:
                return new Fragment2();
            case 2:
                return new Fragment3();
        }
        return null;
    }

    @Override
    public int getCount() {
        return 3;
    }
}

 

最终结合代码

vp = findViewById(R.id.vp);
myFragmentAdapter = new MyFragmentAdapter(getSupportFragmentManager());
vp.setAdapter(myFragmentAdapter);