Android Kotlin 底部导航栏

Question

我使用底部导航栏(默认情况下为 xx_activity 底部)，但我遇到了问题。当我点击该项目时它没问题， Activity 很好但 Activity 的项目没有改变......

import android.content.Intent
import android.os.Bundle
import android.support.design.widget.BottomNavigationView
import android.support.v7.app.AppCompatActivity
import kotlinx.android.synthetic.main.activity_grammaire.*

class GrammaireActivity : AppCompatActivity() {

    private val mOnNavigationItemSelectedListener=BottomNavigationView.OnNavigationItemSelectedListener { item ->
        when (item.itemId) {
            R.id.navigation_grammaire -> {
                val intent = Intent(this,GrammaireActivity::class.java)
                startActivity(intent)
                return@OnNavigationItemSelectedListener true
            }
            R.id.navigation_situations -> {
                val intent = Intent(this,SituationsActivity::class.java)
                startActivity(intent)
                return@OnNavigationItemSelectedListener true
            }
            R.id.navigation_lexiquefrsa -> {
                val intent = Intent(this,LexiqueFrSaActivity::class.java)
                startActivity(intent)
                return@OnNavigationItemSelectedListener true
            }
            R.id.navigation_lexiquesafr -> {
                val intent = Intent(this,LexiqueSaFrActivity::class.java)
                startActivity(intent)
                return@OnNavigationItemSelectedListener true
            }
            R.id.navigation_infos -> {
                val intent = Intent(this,InfosActivity::class.java)
                startActivity(intent)
                return@OnNavigationItemSelectedListener true
            }
        }
        false
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_grammaire)

        navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener)
    }

}

Answer 1

我认为建议使用带底部导航的 fragment ，而不是 Activity 。使用 onClick，您可以将当前 fragment 替换为点击所标识的 fragment 。