2017-09-14 70 views
1

我似乎无法找出这一个。我有MainActivity并创建了我想要导航到的SecondActivity和ThirdActivity。Android Studio - 导航活动

我在我的MainActivity使用BottomNavigation到活动之间导航:

public class MainActivity extends AppCompatActivity { 

protected BottomNavigationView navigationView; 

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

BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener 
      = new BottomNavigationView.OnNavigationItemSelectedListener() { 

     @Override 
     public boolean onNavigationItemSelected(@NonNull MenuItem item) { 
      switch (item.getItemId()) { 
       case R.id.navigation_menuItem1: 
        Intent intent = new Intent(MainActivity.this, MainActivity.class); 
        startActivity(intent); 
        return true; 
       case R.id.navigation_menuItem2: 
        Intent intent = new Intent(MainActivity.this, SecondActivity.class); 
        startActivity(intent); 
        return true; 
       case R.id.navigation_menuItem3: 
        Intent intent = new Intent(MainActivity.this, ThirdActivity.class); 
        startActivity(intent); 
        return true; 
      } 
      return false; 
     } 

    }; 

navigationView = (BottomNavigationView) findViewById(R.id.navigation); 
navigationView.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener); 

任何线索,为什么它不切换页面/活动?

编辑:添加这些行,使其工作:

protected BottomNavigationView navigationView; 

navigationView = (BottomNavigationView) findViewById(R.id.navigation); 
navigationView.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener); 

感谢您的帮助!

+0

检查是否当你点击menuItem ,如果它正在调用正确的案例子句 – joao86

+0

我将日志添加到每个案例,但它不会输出任何内容到控制台。 – user8606632

+0

然后,由于没有被调用,所以监听器出现问题。请把你的主要活动 – joao86

回答

1

万一你错过了什么,请确保你没有忘记的事:

在布局的XML创建BottomNavigationView:

<android.support.design.widget.BottomNavigationView 
     android:id="@+id/navigation" 
     android:layout_width="0dp" 
     android:layout_height="wrap_content" 
     android:layout_marginEnd="0dp" 
     android:layout_marginStart="0dp" 
     android:background="?android:attr/windowBackground" 
     app:layout_constraintBottom_toBottomOf="parent" 
     app:layout_constraintLeft_toLeftOf="parent" 
     app:layout_constraintRight_toRightOf="parent" 
     app:menu="@menu/navigation" /> 

在菜单资源在这里navigation.xml创建一个文件夹。此文件用于BottomNavigationView

提供的MenuItems
<?xml version="1.0" encoding="utf-8"?> 
<menu xmlns:android="http://schemas.android.com/apk/res/android"> 

    <item 
     android:id="@+id/navigation_menuItem1" 
     android:icon="@drawable/ic_home_black_24dp" 
     android:title="@string/menuItem1" /> 

    <item 
     android:id="@+id/navigation_menuItem2" 
     android:icon="@drawable/ic_dashboard_black_24dp" 
     android:title="@string/menuItem2" /> 

    <item 
     android:id="@+id/navigation_menuItem3" 
     android:icon="@drawable/ic_notifications_black_24dp" 
     android:title="@string/menuItem3" /> 


</menu> 

现在可以设置监听的Click事件OnNavigationItemSelectedListener和OnNavigationItemReselectedListener上的菜单项:

private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener 
      = new BottomNavigationView.OnNavigationItemSelectedListener() { 

     @Override 
     public boolean onNavigationItemSelected(@NonNull MenuItem item) { 

      switch (item.getItemId()) { 
       case R.id.navigation_menuItem1: 
        return true; 

       case R.id.navigation_menuItem2: 
        return true; 

       case R.id.navigation_menuItem3: 
        return true; 


      } 
      return true; 
     } 

    }; 

    private BottomNavigationView.OnNavigationItemReselectedListener mOnNavigationItemReselectedListener = new BottomNavigationView.OnNavigationItemReselectedListener() { 
     @Override 
     public void onNavigationItemReselected(@NonNull MenuItem item) { 

      switch (item.getItemId()) { 

       case R.id.navigation_menuItem1: 
        Log.d(TAG, "navigation_menuItem1 Reselected ==="); 
        break; 

       case R.id.navigation_menuItem2: 
        Log.d(TAG, "navigation_menuItem2 Reselected ==="); 
        break; 

       case R.id.navigation_menuItem3: 
        Log.d(TAG, "navigation_menuItem3 Reselected ==="); 
        break; 

      } 

     } 
    }; 

bottomNavigationView.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener); 

bottomNavigationView.setOnNavigationItemReselectedListener(mOnNavigationItemReselectedListener); 

编辑 添加到您的onCreate()

BottomNavigationView bottomNavigationView; 
bottomNavigationView = findViewById(R.id.navigation); 
+0

文件结构全部包括您列出的XML文件。我添加了点击监听器代码,但是我在最后两行发现错误:BottomNavigationView.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener); – user8606632

+0

检查我编辑的答案。 – Orvenito

+0

这仍然给我错误,不会验证。什么工作是在onCreate方法上面添加这个: protected BottomNavigationView navigationView; 而这个BottomNavigationView代码之后: navigationView =(BottomNavigationView)findViewById(R.id.navigation); navigationView.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener); – user8606632