我正在尝试克隆 Instagram。使用 mvvm 和数据绑定。我的主页运行良好，但当我进入详细信息页面时，我看不到我的帖子的图片、用户的电子邮件、用户的照片。我认为数据绑定正在获取我的视图模型的空值。所以我决定使用 init 函数。我发送 postId 作为参数。但它仍然是一样的。我看不到我的照片。我看到默认的 android 矢量。这些是我的代码。感谢您的帮助。 ->
package com.example.firebasedeneme.views
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.widget.Toast
import androidx.databinding.DataBindingUtil
import androidx.lifecycle.Observer
import androidx.lifecycle.ViewModelProvider
import androidx.lifecycle.get
import androidx.recyclerview.widget.LinearLayoutManager
import com.example.firebasedeneme.mvvm.DetailedPostViewmodel
import com.example.firebasedeneme.R
import com.example.firebasedeneme.adapter.CommentsAdapter
import com.example.firebasedeneme.databinding.ActivityDetailedPostBinding
import com.example.firebasedeneme.model.Comment
import com.example.firebasedeneme.model.Post
import com.example.firebasedeneme.mvvm.MyViewmodelFactory
import com.google.firebase.auth.ktx.auth
import com.google.firebase.ktx.Firebase
class DetailedPostActivity : AppCompatActivity() {
val auth = Firebase.auth
private lateinit var binding: ActivityDetailedPostBinding
private lateinit var viewmodel: DetailedPostViewmodel
lateinit var post: Post
private lateinit var adapter: CommentsAdapter
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = DataBindingUtil.setContentView(this, R.layout.activity_detailed_post)
binding.homePageActivity = HomePageActivity()
binding.commentRecyclerView.layoutManager = LinearLayoutManager(this@DetailedPostActivity)
adapter = CommentsAdapter(arrayListOf())
binding.commentRecyclerView.adapter = adapter
post = intent.getSerializableExtra("post") as Post
viewmodel = ViewModelProvider(this, MyViewmodelFactory(application, post.postId))
.get(DetailedPostViewmodel::class.java)
binding.detailedPostVM = viewmodel
viewmodel.getData(post.postId)
observeLiveData()
}
fun observeLiveData() {
viewmodel.postLiveData.observe(this@DetailedPostActivity, Observer { post ->
binding.detailedPost.visibility = View.VISIBLE
})
viewmodel.commentsLiveData.observe(this@DetailedPostActivity, Observer { commentList ->
if (!commentList.isEmpty()) {
binding.commentRecyclerView.adapter = adapter
adapter.yorumlariGuncelle(commentList)
binding.commentRecyclerView.visibility = View.VISIBLE
binding.nullCommentText.visibility = View.GONE
} else {
binding.commentRecyclerView.visibility = View.GONE
binding.nullCommentText.visibility = View.VISIBLE
}
})
viewmodel.nullLiveData.observe(this@DetailedPostActivity, Observer { bool ->
if (bool) {
binding.nullCommentText.visibility = View.VISIBLE
binding.commentRecyclerView.visibility = View.GONE
} else {
binding.nullCommentText.visibility = View.GONE
}
})
}
fun send(view: View) {
val commentText = binding.commentText.text.toString()
binding.commentText.text.clear()
if (!commentText.isEmpty()) {
val comment = Comment(auth.uid!!, post.postId, commentText)
viewmodel.addComment(comment)
adapter.notifyDataSetChanged()
}else{
Toast.makeText(this@DetailedPostActivity, "Yorum Yazınız!", Toast.LENGTH_LONG).show()
}
}
fun like(view: View){
val userId = auth.uid
val user = HomePageActivity.hashMapUsers.get(userId)
user?.let {user->
if(user.userId in post.likedUsers){
post.likedUsers.remove(user.userId)
}else{
post.likedUsers.add(user.userId)
}
adapter.notifyDataSetChanged()
}
}
}
package com.example.firebasedeneme.mvvm
import android.app.Application
import android.widget.Toast
import androidx.lifecycle.AndroidViewModel
import androidx.lifecycle.MutableLiveData
import com.example.firebasedeneme.model.Comment
import com.example.firebasedeneme.model.Post
import com.google.firebase.Timestamp
import com.google.firebase.auth.ktx.auth
import com.google.firebase.firestore.Query
import com.google.firebase.firestore.ktx.firestore
import com.google.firebase.ktx.Firebase
class DetailedPostViewmodel(application: Application,val postId: String) : AndroidViewModel(application) {
val auth = Firebase.auth
val firestore = Firebase.firestore
val postLiveData = MutableLiveData<Post>()
val commentsLiveData = MutableLiveData<ArrayList<Comment>>()
val nullLiveData = MutableLiveData<Boolean>()
val commentList = ArrayList<Comment>()
init {
getData(postId)
}
fun getData(postId:String) {
nullLiveData.value = false
//******İLGİLİ POSTU ALIYORUZ**********
firestore.collection("Posts").document(postId).get().addOnSuccessListener {
val hashmap = it.data
hashmap?.let{hashmap->
val userId = hashmap["userId"] as? String
val imageUrl = hashmap["imageUrl"] as? String
val outline = hashmap["outline"] as? String
if(userId != null && imageUrl != null && outline != null){
val post = Post(userId,imageUrl,outline)
postLiveData.value = post
}
}
}
//**************YORUMLARI ALIYORUZ*************
firestore.collection("Posts").document(postId)
.collection("Comments").orderBy("date",Query.Direction.DESCENDING)
.addSnapshotListener { value, error ->
if (error != null) {
Toast.makeText(getApplication(), error.localizedMessage, Toast.LENGTH_LONG)
.show()
} else {
if (value != null && !value.isEmpty) {
val documents = value.documents
commentList.clear()
for (document in documents) {
val commentMap = document.get("comment") as? Map<String, Any>
commentMap?.let { map ->
val userId = map["userId"] as? String
val commentText = map["commentText"] as? String
if (userId != null && commentText != null) {
commentList.add(Comment(userId, postId, commentText))
}
}
}
println(commentList)
commentsLiveData.value = commentList
} else {
nullLiveData.value = true
}
}
}
}
fun addComment(comment:Comment){
firestore.collection("Posts").document(comment.postId)
.collection("Comments")
.add(hashMapOf("comment" to comment,"date" to Timestamp.now()))
.addOnSuccessListener {
Toast.makeText(getApplication(),"YORUMUNUZ PAYLAŞILDI!",Toast.LENGTH_SHORT).show()
getData(comment.postId)
}.addOnFailureListener {
Toast.makeText(getApplication(),"YORUM YAPILAMADI!",Toast.LENGTH_LONG).show()
}
}
fun isAlreadyLiked() : Boolean{
postLiveData.value?.let {
return it.likedUsers.contains(auth.uid)
}
return false
}
}
package com.example.firebasedeneme.mvvm
import android.app.Application
import androidx.lifecycle.ViewModel
import androidx.lifecycle.ViewModelProvider
class MyViewmodelFactory(val application: Application,val postId: String) : ViewModelProvider.AndroidViewModelFactory(application){
override fun <T : ViewModel> create(modelClass: Class<T>): T {
return DetailedPostViewmodel(application, postId) as T
}
}
@BindingAdapter("android:downloadUrl")
fun downloadImage(view: ImageView, url:String?) {
view.downloadFromUrl(url, placeholderProgressBar(view.context))
}
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android">
<data>
<variable
name="detailedPostVM"
type="com.example.firebasedeneme.mvvm.DetailedPostViewmodel" />
<variable
name="homePageActivity"
type="com.example.firebasedeneme.views.HomePageActivity" />
</data>
<androidx.core.widget.NestedScrollView android:layout_height="wrap_content" android:layout_width="wrap_content">
<LinearLayout android:id="@+id/detailedPost"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<ImageView
android:id="@+id/profilePhotoImageView"
android:layout_width="99dp"
android:layout_height="72dp"
android:downloadUrl="@{homePageActivity.Companion.hashMapUsers.get(detailedPostVM.postLiveData.userId).userPhotoUrl}"/>
<TextView
android:id="@+id/postEmailText"
android:layout_width="306dp"
android:layout_height="match_parent"
android:gravity="center"
android:paddingRight="200dp"
android:text="@{homePageActivity.Companion.hashMapUsers.get(detailedPostVM.postLiveData.userId).email}" />
</LinearLayout>
<TextView
android:id="@+id/postOutlineText"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textAlignment="center"
android:text="@{detailedPostVM.postLiveData.outline}"/>
<ImageView
android:id="@+id/postImageView"
android:layout_width="249dp"
android:layout_height="207dp"
android:layout_gravity="left"
android:layout_marginLeft="20dp"
android:downloadUrl="@{detailedPostVM.postLiveData.imageUrl}"/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<TextView
android:id="@+id/likeCountDetail"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:textColor="#2E53BD"
android:textSize="12sp"
android:gravity="left"
android:text='@{String.valueOf(detailedPostVM.postLiveData.likedUsers.size)+" people liked"}'
android:paddingLeft="10dp"/>
</LinearLayout>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:orientation="horizontal">
<Button
android:id="@+id/likeBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:contentDescription="likeBtn"
android:text='@{detailedPostVM.alreadyLiked ? "LIKED" : "LIKE"}'
android:onClick="like"/>
<EditText
android:id="@+id/commentText"
android:layout_width="200dp"
android:layout_height="wrap_content"
android:hint="Yorum Yap..."
android:textSize="22sp"/>
<Button
android:id="@+id/sendBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="SEND"
android:onClick="send"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/commentRecyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="20dp"
android:nestedScrollingEnabled="false"/>
<TextView
android:id="@+id/nullCommentText"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="NO ANY COMMENT!"
android:textAlignment="center"
android:textSize="32sp" />
</LinearLayout>
</LinearLayout>
</androidx.core.widget.NestedScrollView>
</layout>
我刚刚添加了 binding.lifecyclyeOwner = this; 已经解决了。