Question

我无法构建相应的代码..它在manager.beginTransaction（）下显示红线。替换（R.id.relativelayout_for_fragment，attendanceFragment）.commit（）;我该怎么办？

public class HomeActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {

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

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

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

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.home, 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_attendance) {
            Toast.makeText(HomeActivity.this, "Attendance", Toast.LENGTH_SHORT).show();
            AttendanceFragment attendanceFragment = new AttendanceFragment();
            FragmentManager manager = getSupportFragmentManager();
            manager.beginTransaction().replace(R.id.relativelayout_for_fragment, attendanceFragment).commit();



        } else if (id == R.id.nav_marklist) {
            Toast.makeText(HomeActivity.this, "Mark List", Toast.LENGTH_SHORT).show();
        } else if (id == R.id.nav_studentdetails) {
            Toast.makeText(HomeActivity.this, "Student Details", Toast.LENGTH_SHORT).show();
        } else if (id == R.id.nav_settings) {
            Toast.makeText(HomeActivity.this, "Settings", Toast.LENGTH_SHORT).show();
        } else if (id == R.id.nav_sendsms) {
            Toast.makeText(HomeActivity.this, "Send SMS", Toast.LENGTH_SHORT).show();
        } else if (id == R.id.nav_about) {
            Toast.makeText(HomeActivity.this, "About", Toast.LENGTH_SHORT).show();
        }

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

Answer 1

replace方法有以下签名

replace(int containerViewId, Fragment fragment)

所以第二个参数需要instanceof Fragment。因此，AttendanceFragment应扩展Fragment类

错误的第二个参数类型，方法FragmentTransaction不适用

1 个答案: