如何根据活动/视图更改导航抽屉中的选定项目？

Question

我有一个导航抽屉活动和不同的活动。我希望根据活动选择导航抽屉中的项目或查看任何内容。

public class MainActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                Intent intent = new Intent(view.getContext(), MainAddMedActivity.class);
                /*EditText editText = (EditText) findViewById(R.id.search_medicament);
                String medicament_search = editText.getText().toString();*/
                /*intent.putExtra(EXTRA_MESSAGE, medicament_search);*/
                startActivity(intent);
            }
        });

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.setDrawerListener(toggle);
        toggle.syncState();

        NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this);

        navigationView.getMenu().getItem(0).setChecked(true);


    }

    @Override
    public void onBackPressed() {
        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        if (drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }


        /*navigationView.getMenu().getItem(0).setChecked(true);*/
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @SuppressWarnings("StatementWithEmptyBody")
    @Override
    public boolean onNavigationItemSelected(MenuItem item) {
        // Handle navigation view item clicks here.
        int id = item.getItemId();

        if (id == R.id.nav_healthdiary) {

        } else if (id == R.id.nav_appointment) {

        } else if (id == R.id.nav_physician) {

        } else if (id == R.id.nav_protocol) {

        } else if (id == R.id.nav_share) {

        } else if (id == R.id.nav_send) {

        }

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        drawer.closeDrawer(GravityCompat.START);
        return true;

例如，我进入MainAddMedActivity 并按返回。然后我想要一些代码来检查我在哪个视图或活动中并在导航抽屉中选择项目。

Answer 1

好像你还没有实现内容区的切换。我建议你为此使用片段。 因此，如果您使用片段，请覆盖您的活动的 onAttachFragment，例如：

@Override
public void onAttachFragment(Fragment fragment) {
    super.onAttachFragment(fragment);
    int id;
    if(fragment instanceof HealthDiaryFragment) id = R.id.nav_healthdiary;
    else
    if(fragment instanceof AppointmentFragment) id = R.id.nav_appointment;
    ...
    else return;
    NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
    navigationView.setCheckedItem(id);
}

另外，修改你的 onBackPressed：

@Override
public void onBackPressed() {
    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    if (drawer.isDrawerOpen(GravityCompat.START)) {
        drawer.closeDrawer(GravityCompat.START);
    } else {
        if(getFragmentManager().getBackStackEntryCount()>1) {
            getFragmentManager().popBackStack();
        }
        else {
            super.onBackPressed();
        }
    }


    /*navigationView.getMenu().getItem(0).setChecked(true);*/
}

这是假设在您处理抽屉选择时，您将片段替换为将它们推入后堆栈。