我的主要活动显示空RecyclerView。我的CardView未显示。
数据存储在Firebase数据库中，但由于某种原因不会显示。
我也在网上搜索过，但没有任何帮助。我尝试了网上和Stack Overflow上列出的所有内容。
MainActivity.java
public class MainActivity1 extends AppCompatActivity {
private RecyclerView mQuestionList;
private CardView mCardVieww;
private DatabaseReference mDatabase;
private FirebaseAuth mAuth;
private FirebaseAuth.AuthStateListener mAuthListener;
private DatabaseReference mDatabaseUsers;
private LinearLayoutManager layoutManager;
private DatabaseReference mDatabaseCurrentUsers;
private DatabaseReference mDatabaseLike;
private boolean mProcessLike = false;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main1);
mAuth=FirebaseAuth.getInstance();
mAuthListener=new FirebaseAuth.AuthStateListener() {
@Override
public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
if (firebaseAuth.getCurrentUser()== null){
Intent loginIntent=new Intent(MainActivity1.this,LoginActivity.class);
loginIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(loginIntent);
}
}
};
mDatabase= FirebaseDatabase.getInstance().getReference().child("Question");
mDatabaseUsers=FirebaseDatabase.getInstance().getReference().child("Users");
mDatabaseLike=FirebaseDatabase.getInstance().getReference().child("Likes");
mDatabaseUsers.keepSynced(true);
mDatabaseLike.keepSynced(true);
mDatabase.keepSynced(true);
mQuestionList=(RecyclerView) findViewById(R.id.question_list);
layoutManager=new LinearLayoutManager(this);
layoutManager.setReverseLayout(true);
layoutManager.setStackFromEnd(true);
mQuestionList.setHasFixedSize(true);
mQuestionList.setLayoutManager(layoutManager);
checkUserExist();
}
@Override
protected void onStart() {
super.onStart();
mAuth.addAuthStateListener(mAuthListener);
FirebaseRecyclerAdapter <Question,QuestionViewHolder> fireRecyclerAdapter = new FirebaseRecyclerAdapter <Question,QuestionViewHolder>(
Question.class,
R.layout.question,
QuestionViewHolder.class,
mDatabase
){
@Override
protected void populateViewHolder(QuestionViewHolder viewHolder,Question model, int position){
final String post_key = getRef(position).getKey()
viewHolder.setTitle(model.getTitle());
viewHolder.setDesc(model.getDesc());
viewHolder.setImage(getApplicationContext(),model.getImage());
viewHolder.setUsername(model.getUsername());
viewHolder.setLikeBtn(post_key);
viewHolder.mView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// Toast.makeText(MainActivity1.this,post_key,Toast.LENGTH_LONG).show();
Intent singleQuestionIntent=new Intent(MainActivity1.this,QuestionSingleActivity.class);
singleQuestionIntent.putExtra("question_id",post_key);
startActivity(singleQuestionIntent);
}
});
viewHolder.mLikeBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
mProcessLike = true;
mDatabaseLike.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (mProcessLike) {
if (dataSnapshot.child(post_key).hasChild(mAuth.getCurrentUser().getUid())) {
mDatabaseLike.child(post_key).child(mAuth.getCurrentUser().getUid()).removeValue();
mProcessLike = false;
} else {
mDatabaseLike.child(post_key).child(mAuth.getCurrentUser().getUid()).setValue("RandomValue");
mProcessLike = false;
}
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
});
}
};
mQuestionList.setHasFixedSize(true);
mQuestionList.setLayoutManager(layoutManager);
mQuestionList.setAdapter(fireRecyclerAdapter);
}
//cgeck user exist or not
private void checkUserExist() {
if (mAuth.getCurrentUser() != null) {
final String user_id = mAuth.getCurrentUser().getUid();
mDatabaseUsers.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (!dataSnapshot.hasChild(user_id)) {
Intent setupIntent = new Intent(MainActivity1.this, SetupActivity.class);
setupIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(setupIntent);
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
}
public static class QuestionViewHolder extends RecyclerView.ViewHolder{
View mView;
ImageButton mLikeBtn;
DatabaseReference mDatabaseLike;
FirebaseAuth mAuth;
public QuestionViewHolder(View itemView) {
super(itemView);
mView=itemView;
mLikeBtn=(ImageButton) mView.findViewById(R.id.likeBtn);
mDatabaseLike= FirebaseDatabase.getInstance().getReference().child("Likes");
mAuth=FirebaseAuth.getInstance();
mDatabaseLike.keepSynced(true);
}
public void setLikeBtn(final String post_key){
mDatabaseLike.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (dataSnapshot.child(post_key).hasChild(mAuth.getCurrentUser().getUid())){
mLikeBtn.setImageResource(R.mipmap.thumb_grey);
}else{
mLikeBtn.setImageResource(R.mipmap.thumb_grey);
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
public void setTitle(String title){
TextView post_title=(TextView) mView.findViewById(R.id.post_title);
post_title.setText(title);
}
public void setDesc(String desc){
TextView post_desc=(TextView) mView.findViewById(R.id.post_desc);
post_desc.setText(desc);
}
public void setUsername(String username){
TextView post_username=(TextView) mView.findViewById(R.id.post_username);
post_username.setText(username);
}
public void setImage(final Context ctx, final String image){
final ImageView post_image=(ImageView) mView.findViewById(R.id.post_image);
//Picasso.with(ctx).load(image).into(post_image);
Picasso.with(ctx).load(image).networkPolicy(NetworkPolicy.OFFLINE).into(post_image, new Callback() {
@Override
public void onSuccess() {
}
@Override
public void onError() {
Picasso.with(ctx).load(image).into(post_image);
}
});
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main_menu,menu);
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
if(item.getItemId()==R.id.action_add){
startActivity(new Intent(MainActivity1.this,PostActivity.class));
}
if(item.getItemId()==R.id.action_logout){
logout();
}
if(item.getItemId()==R.id.action_Qp){
startActivity(new Intent(MainActivity1.this,MainActivity2.class));
}
return super.onOptionsItemSelected(item);
}
private void logout() {
mAuth.signOut();
}
}
Question.java
public class Question {
private CardView mCardView;
private String title;
private String desc;
private String image;
private String username;
public Question(){
}
public Question(String title, String desc, String image,String username) {
this.title = title;
this.desc = desc;
this.image = image;
this.username = username;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getDesc() {
return desc;
}
public void setDesc(String desc) {
this.desc = desc;
}
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;
}
}
activity_main1.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.akhil.rtmnuforum.MainActivity1">
<android.support.v7.widget.RecyclerView
android:id="@+id/question_list"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/background">
</android.support.v7.widget.RecyclerView>
</LinearLayout>
question.xml
<?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"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/cardview"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="20dp"
android:visibility="visible"
tools:context="com.example.akhil.rtmnuforum.MainActivity1">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<ImageView
android:id="@+id/post_image"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:adjustViewBounds="true"
android:scaleType="centerCrop"
android:src="@mipmap/add_btn" />
<TextView
android:id="@+id/post_title"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="15dp"
android:text="Post Title Goes here"
android:textSize="16dp"
android:textStyle="bold" />
<TextView
android:id="@+id/post_desc"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingBottom="15dp"
android:paddingLeft="15dp"
android:paddingRight="15dp"
android:text="Question Description Goes here" />
<TextView
android:id="@+id/post_username"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingBottom="15dp"
android:paddingLeft="15dp"
android:paddingRight="15dp"
android:text="username"
android:textSize="12dp"
android:textStyle="bold" />
<ImageButton
android:id="@+id/likeBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:background="@color/cardview_light_background"
app:srcCompat="@mipmap/ic_thumb_up_black_24dp" />
</LinearLayout>
</android.support.v7.widget.CardView>