我的SearchActivity在搜索时不会向用户显示

Question

我的SearchActivity不会向用户显示。没有显示错误，但是searchForMatch和updateUsersList之间一定有问题，因为在logcat中显示的最后一个日志是（TAG，“searchForMatch：搜索匹配：”+关键字）;我觉得那段代码肯定有问题，但我不知道:(也许Firebase出了问题？请帮忙。

import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.text.Editable;
import android.text.TextWatcher;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.inputmethod.InputMethodManager;
import android.widget.AdapterView;
import android.widget.EditText;
import android.widget.ListView;

import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.Query;
import com.google.firebase.database.ValueEventListener;
import com.ittianyu.bottomnavigationviewex.BottomNavigationViewEx;
import com.stek.ca_ltd.memestackupdating.Profile.ProfileActivity;
import com.stek.ca_ltd.memestackupdating.R;
import com.stek.ca_ltd.memestackupdating.Utils.BottomNavigationViewHelper;
import com.stek.ca_ltd.memestackupdating.Utils.UserListAdapter;
import com.stek.ca_ltd.memestackupdating.models.User;

import java.util.ArrayList;
import java.util.List;
import java.util.Locale;


/**
 * Created by User on 5/28/2017.
 */
public class SearchActivity extends AppCompatActivity{
    private static final String TAG = "SearchActivity";
    private static final int ACTIVITY_NUM = 1;

    private Context mContext = SearchActivity.this;

    //widgets
    private EditText mSearchParam;
    private ListView mListView;

    //vars
    private List<User> mUserList;
    private UserListAdapter mAdapter;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_search);
        mSearchParam = (EditText) findViewById(R.id.search);
        mListView = (ListView) findViewById(R.id.listView);
        Log.d(TAG, "onCreate: started.");

        hideSoftKeyboard();
        setupBottomNavigationView();
        initTextListener();
    }

    private void initTextListener(){
        Log.d(TAG, "initTextListener: initializing");

        mUserList = new ArrayList<>();

        mSearchParam.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {

            }

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {

            }

            @Override
            public void afterTextChanged(Editable s) {

                String text = mSearchParam.getText().toString().toLowerCase(Locale.getDefault());
                searchForMatch(text);
            }
        });
    }

    private void searchForMatch(String keyword){
        Log.d(TAG, "searchForMatch: searching for a match: " + keyword);
        mUserList.clear();
        //update the users list view
        if(keyword.length() ==0){

        }else{
            DatabaseReference reference = FirebaseDatabase.getInstance().getReference();
            Query query = reference.child(getString(R.string.dbname_users))
                    .orderByChild(getString(R.string.field_username)).equalTo(keyword);
            query.addListenerForSingleValueEvent(new ValueEventListener() {
                @Override
                public void onDataChange(DataSnapshot dataSnapshot) {
                    for(DataSnapshot singleSnapshot :  dataSnapshot.getChildren()){
                        Log.d(TAG, "onDataChange: found user:" + singleSnapshot.getValue(User.class).toString());

                        mUserList.add(singleSnapshot.getValue(User.class));
                        //update the users list view
                        updateUsersList();
                    }
                }

                @Override
                public void onCancelled(DatabaseError databaseError) {

                }
            });
        }
    }

    private void updateUsersList(){
        Log.d(TAG, "updateUsersList: updating users list");

        mAdapter = new UserListAdapter(SearchActivity.this, R.layout.layout_user_listitem, mUserList);

        mListView.setAdapter(mAdapter);

        mListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                Log.d(TAG, "onItemClick: selected user: " + mUserList.get(position).toString());

                //navigate to profile activity
                Intent intent =  new Intent(SearchActivity.this, ProfileActivity.class);
                intent.putExtra(getString(R.string.calling_activity), getString(R.string.search_activity));
                intent.putExtra(getString(R.string.intent_user), mUserList.get(position));
                startActivity(intent);
            }
        });
    }


    private void hideSoftKeyboard(){
        if(getCurrentFocus() != null){
            InputMethodManager imm = (InputMethodManager) getSystemService(INPUT_METHOD_SERVICE);
            imm.hideSoftInputFromWindow(getCurrentFocus().getWindowToken(), 0);
        }
    }


    /**
     * BottomNavigationView setup
     */
    private void setupBottomNavigationView(){
        Log.d(TAG, "setupBottomNavigationView: setting up BottomNavigationView");
        BottomNavigationViewEx bottomNavigationViewEx = (BottomNavigationViewEx) findViewById(R.id.bottomNavViewBar);
        BottomNavigationViewHelper.setupBottomNavigationView(bottomNavigationViewEx);
        BottomNavigationViewHelper.enableNavigation(mContext, this,bottomNavigationViewEx);
        Menu menu = bottomNavigationViewEx.getMenu();
        MenuItem menuItem = menu.getItem(ACTIVITY_NUM);
        menuItem.setChecked(true);
    }
}

和UserListAdapter：

import android.content.Context;
import android.support.annotation.LayoutRes;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;

import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.Query;
import com.google.firebase.database.ValueEventListener;
import com.nostra13.universalimageloader.core.ImageLoader;
import com.stek.ca_ltd.memestackupdating.R;
import com.stek.ca_ltd.memestackupdating.models.User;
import com.stek.ca_ltd.memestackupdating.models.UserAccountSettings;

import java.util.List;

import de.hdodenhof.circleimageview.CircleImageView;

/**
 * Created by User on 9/17/2017.
 */
public class UserListAdapter extends ArrayAdapter<User>{

    private static final String TAG = "UserListAdapter";


    private LayoutInflater mInflater;
    private List<User> mUsers = null;
    private int layoutResource;
    private Context mContext;

    public UserListAdapter(@NonNull Context context, @LayoutRes int resource, @NonNull List<User> objects) {
        super(context, resource, objects);
        mContext = context;
        mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        layoutResource = resource;
        this.mUsers = objects;
    }

    private static class ViewHolder{
        TextView username, email;
        CircleImageView profileImage;
    }


    @NonNull
    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {


        final ViewHolder holder;

        if(convertView == null){
            convertView = mInflater.inflate(layoutResource, parent, false);
            holder = new ViewHolder();

            holder.username = (TextView) convertView.findViewById(R.id.username);
            holder.email = (TextView) convertView.findViewById(R.id.email);
            holder.profileImage = (CircleImageView) convertView.findViewById(R.id.profile_image);

            convertView.setTag(holder);
        }else{
            holder = (ViewHolder) convertView.getTag();
        }


        holder.username.setText(mUsers.get(position).getUsername());
        holder.email.setText(getItem(position).getEmail());

        DatabaseReference reference = FirebaseDatabase.getInstance().getReference();
        Query query = reference.child(mContext.getString(R.string.dbname_user_account_settings))
                .orderByChild(mContext.getString(R.string.field_user_id))
                .equalTo(getItem(position).getUser_id());
        query.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                for(DataSnapshot singleSnapshot: dataSnapshot.getChildren()){
                    Log.d(TAG, "onDataChange: found user: " +
                            singleSnapshot.getValue(UserAccountSettings.class).toString());

                    ImageLoader imageLoader = ImageLoader.getInstance();

                    imageLoader.displayImage(singleSnapshot.getValue(UserAccountSettings.class).getProfile_photo(),
                            holder.profileImage);
                }
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });

        return convertView;
    }
}

Answer 1

我认为您在活动中采取了一些错误的步骤。您正在多次初始化适配器，如果搜索字符串为空，您还清除用户arraylist。我的下面的代码可以帮助您。

import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.text.Editable;
import android.text.TextWatcher;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.inputmethod.InputMethodManager;
import android.widget.AdapterView;
import android.widget.EditText;
import android.widget.ListView;

import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.Query;
import com.google.firebase.database.ValueEventListener;
import com.ittianyu.bottomnavigationviewex.BottomNavigationViewEx;
import com.stek.ca_ltd.memestackupdating.Profile.ProfileActivity;
import com.stek.ca_ltd.memestackupdating.R;
import com.stek.ca_ltd.memestackupdating.Utils.BottomNavigationViewHelper;
import com.stek.ca_ltd.memestackupdating.Utils.UserListAdapter;
import com.stek.ca_ltd.memestackupdating.models.User;

import java.util.ArrayList;
import java.util.List;
import java.util.Locale;


public class SearchActivity extends AppCompatActivity{
    private static final String TAG = "SearchActivity";
    private static final int ACTIVITY_NUM = 1;

    private Context mContext = SearchActivity.this;

    //widgets
    private EditText mSearchParam;
    private ListView mListView;

    //vars
    private List<User> mUserList;
    private List<User> mUserListTemp;
    private UserListAdapter mAdapter;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_search);
        mSearchParam = (EditText) findViewById(R.id.search);
        mListView = (ListView) findViewById(R.id.listView);
        Log.d(TAG, "onCreate: started.");

        mUserList = new ArrayList<>();
        mUserListTemp = new ArrayList<>();

        mAdapter = new UserListAdapter(SearchActivity.this, R.layout.layout_user_listitem, mUserList);

        mListView.setAdapter(mAdapter);

        hideSoftKeyboard();
        setupBottomNavigationView();
        initTextListener();

        mListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                Log.d(TAG, "onItemClick: selected user: " + mUserList.get(position).toString());

                //navigate to profile activity
                Intent intent =  new Intent(SearchActivity.this, ProfileActivity.class);
                intent.putExtra(getString(R.string.calling_activity), getString(R.string.search_activity));
                intent.putExtra(getString(R.string.intent_user), mUserList.get(position));
                startActivity(intent);
            }
        });


    }

    private void initTextListener(){
        Log.d(TAG, "initTextListener: initializing");


        mSearchParam.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {

            }

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {

            }

            @Override
            public void afterTextChanged(Editable s) {

                String text = mSearchParam.getText().toString().toLowerCase(Locale.getDefault());
                searchForMatch(text);
            }
        });
    }

    private void searchForMatch(String keyword){
        Log.d(TAG, "searchForMatch: searching for a match: " + keyword);

        //update the users list view
        if(keyword.length() ==0){

        }else{
            mUserListTemp.clear();
            DatabaseReference reference = FirebaseDatabase.getInstance().getReference();
            Query query = reference.child(getString(R.string.dbname_users))
                    .orderByChild(getString(R.string.field_username)).equalTo(keyword);
            query.addListenerForSingleValueEvent(new ValueEventListener() {
                @Override
                public void onDataChange(DataSnapshot dataSnapshot) {
                    for(DataSnapshot singleSnapshot :  dataSnapshot.getChildren()){
                        Log.d(TAG, "onDataChange: found user:" + singleSnapshot.getValue(User.class).toString());

                        mUserListTemp.add(singleSnapshot.getValue(User.class));
                        //update the users list view

                    }

                    updateUsersList();
                }

                @Override
                public void onCancelled(DatabaseError databaseError) {

                }
            });
        }
    }

    private void updateUsersList(){
        Log.d(TAG, "updateUsersList: updating users list");

        if(mUserListTemp.size()>0)
        {
            mUserList.clear();
            mUserList.addAll(mUserListTemp);
            mAdapter.notifyDataSetChanged();
        }
    }


    private void hideSoftKeyboard(){
        if(getCurrentFocus() != null){
            InputMethodManager imm = (InputMethodManager) getSystemService(INPUT_METHOD_SERVICE);
            imm.hideSoftInputFromWindow(getCurrentFocus().getWindowToken(), 0);
        }
    }


    /**
     * BottomNavigationView setup
     */
    private void setupBottomNavigationView(){
        Log.d(TAG, "setupBottomNavigationView: setting up BottomNavigationView");
        BottomNavigationViewEx bottomNavigationViewEx = (BottomNavigationViewEx) findViewById(R.id.bottomNavViewBar);
        BottomNavigationViewHelper.setupBottomNavigationView(bottomNavigationViewEx);
        BottomNavigationViewHelper.enableNavigation(mContext, this,bottomNavigationViewEx);
        Menu menu = bottomNavigationViewEx.getMenu();
        MenuItem menuItem = menu.getItem(ACTIVITY_NUM);
        menuItem.setChecked(true);
    }
}