Android導航抽屜.commit問題

Question

昨天我試圖創建一個導航抽屜。在我的源代碼中，「R.id.content_frame」和「.commit」總是用紅色標出。 任何人都可以幫助我嗎？

import android.os.Bundle; 
import android.support.design.widget.FloatingActionButton; 
import android.support.design.widget.Snackbar; 
import android.support.v4.app.FragmentManager; 
import android.view.View; 
import android.support.design.widget.NavigationView; 
import android.support.v4.view.GravityCompat; 
import android.support.v4.widget.DrawerLayout; 
import android.support.v7.app.ActionBarDrawerToggle; 
import android.support.v7.app.AppCompatActivity; 
import android.support.v7.widget.Toolbar; 
import android.view.Menu; 
import android.view.MenuItem; 

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) { 
       Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG) 
         .setAction("Action", null).show(); 
      } 
     }); 

     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); 
    } 

    @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.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(); 
     android.app.FragmentManager fragmentManager = getFragmentManager();| 

     if (id == R.id.nav_first_layout) { 
      fragmentManager.beginTransaction() 
        .replace(R.id.content_frame) 
          , new FirstFragment() 
      .commit(); 
     } else if (id == R.id.nav_second_layout) { 
      fragmentManager.beginTransaction() 
        .replace(R.id.content_frame) 
        , new SecondFragment()) 
      .commit(); 
     } else if (id == R.id.nav_third_layout) { 
      fragmentManager.beginTransaction() 
        .replace(R.id.content_frame) 
        , new ThirdFragment() 
        .commit(); 
     } 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; 
    } 
    } 

Answer 1

你有問題，用括號：

而不是

fragmentManager.beginTransaction() 
        .replace(R.id.content_frame) 
          , new FirstFragment() 
      .commit(); 

你應該有

fragmentManager.beginTransaction() 
      .replace(R.id.content_frame, new FirstFragment()) 
      .commit(); 

Here is reference to FragmentTransaction#replace method

片段是r的PARAM eplace方法。

Answer 2

嘗試與此：

FragmentTransaction fragmentManager = getSupportFragmentManager（）的BeginTransaction（）;

fragmentManager.replace（R.id.content_frame，new SecondFragment（））; fragmentManager.commit（）;