如何在导航活动中使用按钮在片段之间切换

我刚刚在Android Studio上发布新内容，请耐心等待。我创建了两个片段，名为locate_before和locate_after。我有一个ID为的按钮触发我的locate_before片段。点击该按钮后，我想切换到locate_after。如何在导航活动中使用按钮在片段之间切换

这是我的主要活动。我为我的碎片使用了一个框架容器。我已经为我想要的名称创建了一个代码onSelectFragment但它不起作用。它说： “法onSelectFragment从未使用过”

是OFC

import android.os.Bundle; 
import android.support.design.widget.NavigationView; 
import android.support.v4.app.Fragment; 
import android.support.v4.app.FragmentManager; 
import android.support.v4.app.FragmentTransaction; 
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; 
import android.view.View; 
import android.widget.Button; 

public class MainActivity extends AppCompatActivity 
     implements NavigationView.OnNavigationItemSelectedListener { 

    Button trigger; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 

     //Set the fragment initially 
     locate_before fragment = new locate_before(); 
     android.support.v4.app.FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction(); 
     fragmentTransaction.replace(R.id.fragment_container, fragment); 
     fragmentTransaction.commit(); 

     FragmentManager fm = getSupportFragmentManager(); 
     FragmentTransaction transaction = fm.beginTransaction(); //check this out 

     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.setDrawerListener(toggle); 
     toggle.syncState(); 

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

    } 

    public void onSelectFragment(View v){ 
     Fragment newFragment; 

     if(v == findViewById(R.id.trigger)){ 
      newFragment = new locate_after(); 
     } 
     else{ 
      newFragment = new locate_before(); 
     } 

     FragmentTransaction transaction = getSupportFragmentManager().beginTransaction(); 
     transaction.replace(R.id.fragment_container, newFragment); 
     transaction.addToBackStack(null); 
     transaction.commit(); 
    } 



    @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(); 

     if (id == R.id.nav_camera) { 
      // Handle the camera action 
     } else if (id == R.id.nav_gallery) { 

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

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

     } 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; 
    } 

}

locate_before片段的Java扩展片段

public locate_before() { 
     // Required empty public constructor 

    } 

    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
          Bundle savedInstanceState) { 
     View rootView = inflater.inflate(R.layout.fragment_locate_before, container, false); 

     // Inflate the layout for this fragment 
     return rootView; 
    } 
}

locate_before XML文件按钮

<Button 
     android:id="@+id/trigger" 
     android:layout_width="284dp" 
     android:layout_height="58dp" 
     android:text="View Car's Location" 
     android:layout_marginRight="24dp" 
     app:layout_constraintRight_toRightOf="parent" 
     android:layout_marginLeft="8dp" 
     app:layout_constraintLeft_toLeftOf="parent" 
     app:layout_constraintHorizontal_bias="0.633" 
     app:layout_constraintBottom_toBottomOf="parent" 
     android:layout_marginBottom="133dp" />

locate_after的Java

public class locate_after extends Fragment { 


    public locate_after() { 
     // Required empty public constructor 
    } 


    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
          Bundle savedInstanceState) { 
     View rootView = inflater.inflate(R.layout.fragment_locate_after, container, false); 

     // Inflate the layout for this fragment 
     return rootView; 
    } 
}

谢谢！

来源

2017-08-16 Grace Tanya

您的buttom似乎没有onClickListener。

在您的XML中添加android:onClick="onSelectFragment"或绑定您的Button并在您的OnCreate中添加onClickListener。

来源

2017-08-16 11:58:52 G00fY

谢谢。我被困在这个问题上好几个小时了，我想念这个小细节。 –

您在onCreate()

FragmentManager fm = getSupportFragmentManager(); 
FragmentTransaction transaction = fm.beginTransaction(); //check this out

来源

2017-08-16 11:51:33

是的，我注意到了，但不知道为什么。我把它放在那里，因为我将在我的public void onSelectFragment上使用FragmentTransaction事务 –

它不应该在那里。所有交易必须提交。 –

谢谢！我现在清除它 –

（）使用onNavigationItemSelected后有未提交的事务导航到片段。下面是示例代码

@Override 
public boolean onNavigationItemSelected(MenuItem item) { 

    // Handle navigation view item clicks here. 
    int id = item.getItemId(); 

    FragmentManager fragmentManager = getSupportFragmentManager(); 

    if (id == R.id.nav_home) { 
     Fragment homeFragment = new HomeFragment(); 
     fragmentManager.beginTransaction().replace(R.id.relative_layout_fragment1, homeFragment, homeFragment.getTag()).commit(); 

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

     Toast.makeText(mContext, "logout", Toast.LENGTH_SHORT).show(); 
    } 

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

来源

2017-08-16 11:55:33

谢谢你的回答，但我非常需要通过使用按钮访问其他片段。我会注意到这一点虽然 –

首先，你永远不会使用方法OnSelectFragment（）。在你的OnCreate方法中添加以下

trigger = (Button) findViewById(R.id.trigger); //get Button 
trigger.setOnClickListener(new View.OnClickListener() { // action to do when button is pressed 
     @Override 
     public void onClick(View view) { 
      if(before) 
       onSelectFragment(new locate_after()); 
      else 
       onSelectFragment(new locate_before()); 
      before = !before; //this makes it a switch 
     } 
    });

宣告属性“之前”沿着其他属性

boolean before = true;

，改变你的onSelectFragment方法如下

public void onSelectFragment(Fragment newFragment){ 

     FragmentTransaction transaction = getSupportFragmentManager().beginTransaction(); 
     transaction.replace(R.id.fragment_container, newFragment); 
     transaction.addToBackStack(null); 
     transaction.commit(); 
    }

来源

2017-08-16 11:59:12 Fragile

谢谢！我已经找到了最简单的方法 –

检查当前显示的片段和设置您的相应地期望片段。尝试下面的代码。

 Fragment fragment = fragmentManager.findFragmentById(R.id.fragment_container); 
     if(!(fragment instanceof locate_before)) { 
      newFragment = new locate_after(); 
     } 
     else{ 
      newFragment = new locate_before(); 
     } 
     getSupportFragmentManager().beginTransaction().replace(newFragment).commit();

来源

2017-08-16 12:00:30

谢谢你，但我已经找到了最简单的方法 –

如何在导航活动中使用按钮在片段之间切换

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