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我正在開發一個應用程序，它需要我從一個卡片視圖中的兩個Firebase數據庫引用中獲取引用。下面是cardview從一個卡片獲取多個Firebase數據庫引用的值查看
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
android:layout_marginRight="35dp"
android:layout_marginLeft="35dp"
android:layout_marginBottom="60dp">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="75dp"
>
<ImageView
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="match_parent"
android:layout_marginBottom="5dp"
android:layout_marginTop="5dp"
android:layout_marginLeft="5dp"
app:srcCompat="@drawable/action_setup"
android:id="@+id/dPicture"/>
<TextView
android:text="Username"
android:layout_width="0dp"
android:layout_weight="4"
android:layout_height="match_parent"
android:gravity="center_vertical"
android:id="@+id/posted_username"
android:paddingLeft="15dp"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:elevation="10dp">
<ImageView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/posted_image"
android:scaleType="centerCrop"
android:adjustViewBounds="true"
android:src="@color/Orange"
/>
<TextView
android:text="Post Title..."
android:padding="15dp"
android:textSize="16dp"
android:textStyle="bold"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/posted_title"/>
<TextView
android:text="Summary..."
android:paddingLeft="15dp"
android:paddingRight="15dp"
android:paddingBottom="15dp"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:maxLength="300"
android:maxLines="5"
android:id="@+id/posted_sharing"/>
</LinearLayout>
</LinearLayout>
</android.support.v7.widget.CardView>
的模型，這是數據庫看起來怎麼樣在火力地堡
{
"Users" : {
"1" : {
"image" : "http://something.com/something",
"name" : "person 1"
},
"2" : {
"image" : "http://someone.com/someone",
"name" : "person 2"
}
},
"posts" : {
"post 1" : {
"content" : "test content 1",
"dPicture" : "http://something.com/something",
"picture" : "http://postimage.com/postimage",
"title" : "test title 1",
"uid" : 1,
"username" : "person 1"
},
"post 2" : {
"content" : "test content 2",
"dPicture" : "http://someone.com/someone",
"picture" : "http://postimage2.com/postimage2",
"title" : "test title 2",
"uid" : 2,
"username" : "person 2"
}
}
}
以及活動代碼
public class MainActivity extends AppCompatActivity {
private RecyclerView mPostedList;
private LinearLayoutManager mLayoutManager;
private DatabaseReference mDatabaseSharings;
private FirebaseAuth mAuth;
private FirebaseUser mCurrentUser;
private FirebaseAuth.AuthStateListener mAuthListener;
private DatabaseReference mDatabaseUsers;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mAuth = FirebaseAuth.getInstance();
mDatabaseSharings = FirebaseDatabase.getInstance().getReference().child("posts");
mDatabaseUsers = FirebaseDatabase.getInstance().getReference().child("Users");
mCurrentUser = mAuth.getCurrentUser();
mDatabaseSharings.keepSynced(true);
final String uid = mCurrentUser.getUid();
//bring user to login activity when auth-state is null
mAuthListener = new FirebaseAuth.AuthStateListener() {
@Override
public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
if (firebaseAuth.getCurrentUser() == null) {
Intent loginIntent = new Intent(MainActivity.this, LoginActivity.class);
loginIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(loginIntent);
}
}
};
//keep users logged in
mDatabaseUsers.keepSynced(true);
mPostedList = (RecyclerView) findViewById(R.id.posted_list);
mPostedList.setHasFixedSize(true);
mPostedList.setLayoutManager(new LinearLayoutManager(this));
}
@Override
protected void onStart() {
super.onStart();
mAuth.addAuthStateListener(mAuthListener);
//your adapter
FirebaseRecyclerAdapter<PostedModel, PostedModelViewHolder> firebaseRecyclerAdapter = new FirebaseRecyclerAdapter<PostedModel, PostedModelViewHolder>(
PostedModel.class, R.layout.posted_row, PostedModelViewHolder.class, mDatabaseSharings
) {
@Override
protected void populateViewHolder(PostedModelViewHolder viewHolder, PostedModel model, int position) {
viewHolder.setTitle(model.getTitle());
viewHolder.setDPicture(getApplicationContext(), model.getDPicture());
viewHolder.setSummary(model.getSummary());
viewHolder.setImage(getApplicationContext(), model.getImage());
viewHolder.setUsername(model.getUsername());
final String post_key = getRef(position).getKey();
viewHolder.mView.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(View view) {
Intent delete_intent = new Intent(MainActivity.this, DeleteActivity.class);
delete_intent.putExtra("blog_id", post_key);
startActivity(delete_intent);
return false;
}
});
viewHolder.mView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent comment_intent = new Intent (MainActivity.this, CommentActivity.class);
comment_intent.putExtra("blog_id", post_key);
startActivity(comment_intent);
}
});
}
};
mPostedList.setAdapter(firebaseRecyclerAdapter);
mLayoutManager = new LinearLayoutManager(MainActivity.this);
mLayoutManager.setReverseLayout(true);
mLayoutManager.setStackFromEnd(true);
mPostedList.setLayoutManager(mLayoutManager);
}
public static class PostedModelViewHolder extends RecyclerView.ViewHolder{
View mView;
public PostedModelViewHolder(View itemView) {
super(itemView);
mView = itemView;
}
public void setTitle(String title){
TextView post_title = (TextView)mView.findViewById(R.id.posted_title);
post_title.setText(title);
}
public void setDPicture(Context ctx, String dPicture){
ImageView post_dPicture = (ImageView) mView.findViewById(R.id.dPicture);
Picasso.with(ctx).load(dPicture).into(post_dPicture);
}
public void setSummary (String summary){
TextView post_summary = (TextView)mView.findViewById(R.id.posted_sharing);
post_summary.setText(summary);
}
public void setImage(Context ctx, String image){
ImageView post_image = (ImageView) mView.findViewById(R.id.posted_image);
Picasso.with(ctx).load(image).into(post_image);
}
public void setUsername (String username){
TextView post_username = (TextView)mView.findViewById(R.id.posted_username);
post_username.setText(username);
}
}
}
當然還有就是PostedModel。類是它的吸氣和吸氣類
public class PostedModel {
private String title;
private String summary;
private String image;
private String dPicture;
private String username;
public PostedModel(){}
public PostedModel(String title, String summary, String image) {
this.title = title;
this.summary = summary;
this.image = image;
this.dPicture = dPicture;
this.username = username;
}
public String getDPicture() {
return dPicture;
}
public void setDPicture(String dPicture) {this.dPicture = dPicture;}
public String getTitle() {
return title;
}
public void setTitle(String title) {this.title = title;}
public String getSummary() {
return summary;
}
public void setSummary(String summary) {
this.summary = summary;
}
public String getImage() {
return image;
}
public void setImage(String image) {
this.image = image;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
}
現在，您可以看到我有一個發佈活動，它將「用戶」數據庫的用戶名以及圖像值傳遞給「posts」數據庫子（dPicture）。但是，當用戶更新他/她的用戶名時，只有「用戶」數據庫中的值發生變化，而不是從現有的「帖子」中更改。
我認爲最有效的方法是使用數據填充視圖這兩個數據庫引用，連接使用用戶的唯一標識，這是「用戶」數據庫中的關鍵和作爲子（uid）在「posts」數據庫中，但我不知道該怎麼做...我附上與盒數據庫的截圖快照的情況下，說明我很迷惑人跟我欠佳的技術語言
因此我們的目標是讓紅色盒裝的數據和它配對的Wi第三個綠色盒裝數據。
非常感謝所有幫助事先！
編輯： 我不知道如果我在正確的軌道與此......就這麼研究後，我認爲這是使用valueEventListener爲我想要得到數據的數據庫做的正確方法從適配器類的內部...
到目前爲止，我得到這個
FirebaseRecyclerAdapter<PostedModel, PostedModelViewHolder> firebaseRecyclerAdapter = new FirebaseRecyclerAdapter<PostedModel, PostedModelViewHolder>(
PostedModel.class, R.layout.posted_row, PostedModelViewHolder.class, mDatabaseSharings
) {
//calling the value from the Summary.java class
@Override
protected void populateViewHolder(final PostedModelViewHolder viewHolder, final PostedModel model, final int position) {
mDatabaseUsers.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
if(dataSnapshot.getKey().toString() == mDatabaseSharings.child("uid").toString()){
viewHolder.setUsername(model.getUsername());
viewHolder.setDPicture(getApplicationContext(), model.getDPicture());
}
viewHolder.setTitle(model.getTitle());
viewHolder.setSummary(model.getSummary());
viewHolder.setImage(getApplicationContext(), model.getImage());
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
但我拿到鑰匙，而不是值傳遞哈哈
嗨@Ambuj感謝您的評論。嗯，我認爲我應該使用valueEventListener，因爲這似乎是每個人都這樣做...我只是不知道如何正確實施它... – Jagmaster