将数据从 Activity 1 中的 Fraggment_A 发送到 Activity 2 中的 Fragment_B

Question

我在 Activity_1 上有一个 Fragment_A 并且每当在 Fragment_A我要开始Activity_2有个Fragment_B

所以我需要从Fragment_A发送一个user_IdActivity 1到activity_2中的Fragment_B。有什么方法可以直接从Frament_A发送数据到Activity_1到Fragment_B 在 Activity_2?

我是一名学生，所以我是初学者，我确实在这里发现了这个问题，但我不知道该怎么做才能解决这个问题我确实找到了一些关于界面的解决方案，但我不知道该怎么做

我不断得到 class_id null

语言：Kotlin

Class : ClassesAdapter

class ClassesAdapter(val c:Fragment,val l:android.content.Context? ,val classeslist: ArrayList<Classes>) : RecyclerView.Adapter <ClassesAdapter.ClassesViewHolder> (){
    lateinit var auth: FirebaseAuth
    lateinit var DataBase : DatabaseReference
    lateinit var DataBase2 : DatabaseReference
    lateinit var clipboardManager: ClipboardManager


    private lateinit var mListener :onItemClickListener

    interface onItemClickListener {

        fun onItemClick(position :Int)

    }

    /*fun setOnItemClickListener(listener : onItemClickListener){

       // mListener=listener

    }*/

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ClassesViewHolder {
        val itemView = LayoutInflater.from(parent.context).inflate(R.layout.class_items2,parent,false)
        //return ClassesViewHolder(itemView,mListener)
        return ClassesViewHolder(itemView,)
    }


  
    
        override fun onBindViewHolder(holder: ClassesViewHolder, position: Int) {
            val currentitem = classeslist[position]
            holder.classname.text = currentitem.name
            holder.classrole.text = currentitem.role
    
            holder.itemView.setOnClickListener {
    
    
                val intent = Intent(l, DetailedClassActivity::class.java)
                intent.putExtra("classId", currentitem.class_id)
                l!!.startActivity(intent)
    
            }

Class : Activity2 谁有我想发送的片段 class_id`

 package com.example.myclass1
    
    import android.content.Intent
    import android.os.Bundle
    import android.widget.Toast
    import androidx.viewpager2.widget.ViewPager2
    import com.example.myclass1.databinding.ActivityDetailedClassBinding
    import com.google.android.material.tabs.TabLayout
    import com.google.android.material.tabs.TabLayoutMediator
    import com.google.firebase.auth.FirebaseAuth
    
class DetailedClassActivity : DrawerBaseActivity() {

    private lateinit var binding: ActivityDetailedClassBinding
    //lateinit var toggle: ActionBarDrawerToggle
    override lateinit var auth: FirebaseAuth

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding= ActivityDetailedClassBinding.inflate(layoutInflater)
        setContentView(binding.root)

        // add it to change the toolbar title's to the activity name
        val actionBar = supportActionBar
        if (actionBar != null) {
            val dynamicTitle: String = HomeActivity::class.java.simpleName
            //Setting a dynamic title at runtime. Here, it displays the current activity name
            actionBar.setTitle("Home")
        }


        // navigate between documents ,notification and chatroom  :  tabLayout
        val tablayout2 : TabLayout =findViewById(R.id.tab_layout2)
        val viewpager21 : ViewPager2 =findViewById(R.id.viewPager21)
        val adapter =PagerAdapter2(supportFragmentManager,lifecycle)
        viewpager21.adapter = adapter
        TabLayoutMediator(tablayout2, viewpager21) { tab, position ->
            when(position){
                0->{tab.text="Documents"}
                1->{tab.text="Note"}
                2->{tab.text="ChatRoom"}
            }
        }.attach()


       

    val intent=getIntent()
    var classId= intent.getStringExtra("classId")
      

fun getMyData(): String? {
    return classId
    }

    }

class : 片段 B

   enter code here
     btnAddcourse.setOnClickListener {
                var nameofthecourse = Coursename.text.toString().trim()
                var course_id :String?=DataBase3.push().key
                
                var classId = arguments?.getString("classId")
               
                
                val dateofthecourse: String = formatTimeStamp()
    
                if (TextUtils.isEmpty(nameofthecourse)) {
                    // No name added
                    Coursename.error = "No name added !! Please enter the name of the class"
                }
                else{
                    courseList.add(Course(course_id,nameofthecourse,dateofthecourse,classId))
                    coursesAdapter.notifyDataSetChanged()
                    Toast.makeText(activity,"Adding Course Success", Toast.LENGTH_SHORT).show()
                    //Toast.makeText(activity,"class_id is null ", Toast.LENGTH_SHORT).show()
                    if (classId != null) {
                        addCourseToDataBase(course_id!!,nameofthecourse,dateofthecourse,classId)
                    }else{
                        Toast.makeText(activity,"class_id is null ", Toast.LENGTH_SHORT).show()
                    }
                }
            }

Answer 1

片段A

button.setOnClickListener { 
    val intent = Intent(requireContext(), Activity2::class.java)
                intent.putExtra("user_Id", user_Id)
                startActivity(intent)
 }

活动2

val intent = getIntent()
val message = intent.getStringExtra("user_Id")

val bundle = Bundle()
bundle.putString("user_Id", message) //the part i updated
val fragmet= fragment_B()   
fragmet.setArguments(bundle)

片段B

override fun onCreateView(
    inflater: LayoutInflater, container: ViewGroup?,
    savedInstanceState: Bundle?
): View? {
    return inflater.inflate(R.layout.fragment_B, container, false)
    val bundle = this.arguments //the part i updated
    val myString = bundle!!.getString("user_Id", "defaultValue") //the part i updated
}

Answer 2

1-阅读单例设计模式在所有应用程序中使用户 ID 全局化

read it to understand

2-Shared Preference : 保存用户 ID 以供所有应用程序使用

Shared Preferences

3-您可以尝试 Navigation Args ：更好地选择性能并可以使用它在您的应用程序中移动

Navigation

将数据从 Activity 1 中的 Fraggment_A 发送到 Activity 2 中的 Fragment_B

Sending data from Fraggment_A in Activity 1 to Fragment_B in Activity 2

java

android

kotlin

android-studio