Question

我是kotlin的新手我正在我的应用程序中添加底栏

val bottomNavigationView = findViewById<View>(R.id.navigation) as BottomNavigationView
    BottomNavigationViewHelper.removeShiftMode(bottomNavigationView)
    bottomNavigationView.setOnNavigationItemSelectedListener { item ->
        var selectedFragment: Fragment? = null
        when (item.itemId) {
            R.id.action_item1 -> selectedFragment = ItemOneFragment.newInstance()
            R.id.action_item2 -> selectedFragment = ItemTwoFragment.newInstance()
            R.id.action_item3 -> selectedFragment = ItemThreeFragment.newInstance()
            R.id.action_item4 -> selectedFragment = ItemThreeFragment.newInstance()
        }
        val transaction = supportFragmentManager.beginTransaction()
        transaction.replace(R.id.frame_layout, selectedFragment)
        transaction.commit()
        true
    }

    //Manually displaying the first fragment - one time only
    val transaction = supportFragmentManager.beginTransaction()
    transaction.replace(R.id.frame_layout, ItemOneFragment.newInstance())
    transaction.commit()

ItemOneFragment.java

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
 import android.view.ViewGroup;
 public class ItemOneFragment extends Fragment {
 public static ItemOneFragment newInstance() {
    ItemOneFragment fragment = new ItemOneFragment();
    return fragment;
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    return inflater.inflate(R.layout.fragment_item_one, container, false);
}}

但我收到错误：类型不匹配必需：ItemOneFragment.newInstance（）处的片段我尝试了所有的东西提前致谢。

Answer 1

您似乎要在包含android.app.Fragment代码的文件中导入bottomNavigationView。 ItemOneFragment.newInstance()会返回android.support.v4.app.Fragment，这与android.app.Fragment不兼容。

将导入更改为android.support.v4.app.Fragment可以解决问题。

如何在Kotlin中加载片段？

1 个答案: