Question

我似乎无法想出这个。我有MainActivity并创建了我希望能够导航到的SecondActivity和ThirdActivity。

我在MainActivity中使用BottomNavigation在活动之间导航：

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);

有什么理由不切换页面/活动？

编辑：添加以下行以使其正常工作：

protected BottomNavigationView navigationView;

和

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

感谢您的帮助！

Answer 1

万一你错过了什么，请确保你没有忘记：

在布局的xml中创建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" />

在菜单资源文件夹中的navigation.xml中创建一个文件。此文件用于在BottomNavigationView

中提供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>

现在让我们在菜单项上设置Click Events OnNavigationItemSelectedListener和OnNavigationItemReselectedListener的监听器：

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);

修改将其添加到您的onCreate()

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

Android Studio - 导航活动

1 个答案: