如何使用导航组件打开具有特定片段的另一个活动？

Question

我正在使用两个活动。一个是 MainActivity，第二个是 NFC。 MainActivity 有nav_graph.xml。

读完NFC后，我想启动MainActivity并移动到MainActivity的某个片段。

我该如何实现？

Answer 1

你可以试试这个：

（在 MainActivity.java 中）

public class SectionsPagerAdapter extends FragmentPagerAdapter {
        public SectionsPagerAdapter(FragmentManager fm) {
            super(fm);
        }
        @Override
        public Fragment getItem(int position) {
            switch(position) {
                case 0:
                    Frag1 frag1 = new Frag1();//this is one activity
                        return frag1;
                case 1:
                    Frag2 frag2 = new Frag2();
                        return frag2;
                default:
                    return null;
            }
        }
        @Override
        public int getCount() {
            return 2; //'the number 2 is 'cause you've got a two activities
        }
    }

如果你想打开另一个带有浮动操作按钮的活动，你可以试试这个：

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
        mViewPager = (ViewPager) findViewById(R.id.container);
        mViewPager.setAdapter(mSectionsPagerAdapter);
        TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
        FloatingActionButton fab = (FloatingActionButton)findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(mViewPager.getCurrentItem()==0){
                    Fragment1();
                    Toast.makeText(MainActivity.this, "Example 1", Toast.LENGTH_SHORT).show();
                }else if(mViewPager.getCurrentItem()==1){
                    Fragmen2();
                    Toast.makeText(MainActivity.this, "Example 2", Toast.LENGTH_SHORT).show();
                }
            }
        });
        mViewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
        tabLayout.addOnTabSelectedListener(new TabLayout.ViewPagerOnTabSelectedListener(mViewPager));
    }
    public void Fragment1(){//Call to the activity Example1
        Intent fragment0 = new Intent(getApplicationContext(), example1.class);
        startActivity(fragment0);
        onResume();
    }
    public void Fragmen2(){ //Call to the activity Example2
        Intent fragment1 = new Intent(getApplicationContext(), example2.class);
        startActivity(fragment1);
        onResume();
    }