我的Firebase RecyclerView在android studio中添加textwatcher后不显示任何内容

如何解决我的Firebase RecyclerView在android studio中添加textwatcher后不显示任何内容

我想要的实际上是一个搜索文本字段以及一个重载于搜索文本字段中文本的recycleview和show适配器。下面的链接是我引用的代码。 How to implement firebase recycler using TextWatcher?

BindView

@BindView(R.id.searchFood) SearchView mSearchFood;
@BindView(R.id.isharedfood_recyclerview) RecyclerView mISharedFoodRecyclerView;

iFoodSharedActivity.java

       @Override
            protected void onCreate(Bundle savedInstanceState) {
   

             super.onCreate(savedInstanceState);
                setContentView(R.layout.activity_ifoodshared);
                ButterKnife.bind(this);
                setSupportActionBar(mToolbar);
                getSupportActionBar().setTitle("iFoodShared");
                getSupportActionBar().setHomeAsUpIndicator(R.drawable.ic_baseline_keyboard_backspace_24);
                getSupportActionBar().setdisplayHomeAsUpEnabled(true);
                getSupportActionBar().setdisplayShowHomeEnabled(true);
                mAuth = FirebaseAuth.getInstance();
                mFirestore = FirebaseFirestore.getInstance();
                itemRef = mFirestore.collection("FoodShare");
                user = mAuth.getCurrentUser().getdisplayName();
                 mSearchFood.setonQueryTextListener(new SearchView.OnQueryTextListener() {
        @Override
        public boolean onQueryTextSubmit(String s) {
            return false;
        }

        @Override
        public boolean onQueryTextChange(String s) {
            s = mSearchFood.getQuery().toString();
            setUpRecyclerView (s);
            return false;
        }
    });
            }
   


    private void setUpRecyclerView(final String s){
    Query query = itemRef
            .orderBy("timeStamp",Query.Direction.DESCENDING)
            .whereEqualTo("sharerName",user)
            .startAt(s.toupperCase()).endAt(s + "\uf8ff");
    FirestoreRecyclerOptions<FoodModel> options = new FirestoreRecyclerOptions.Builder<FoodModel>()
            .setQuery(query,FoodModel.class)
            .build();

    iFoodSharedAdapter = new iFoodSharedAdapter(options);

    RecyclerView recyclerView = findViewById(R.id.isharedfood_recyclerview);
    recyclerView.setLayoutManager(new GridLayoutManager(this,2));
    recyclerView.setAdapter(iFoodSharedAdapter);
}

    @Override
    public void onStart() {
        super.onStart();
        iFoodSharedAdapter.startListening();

    }

    public void onStop() {
        super.onStop();
        iFoodSharedAdapter.stopListening();
    }

显示错误

  E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.fyp.fypfoodbank,PID: 29614
java.lang.NullPointerException: Attempt to invoke virtual method 'void com.fyp.fypfoodbank.Adapters.iFoodSharedAdapter.startListening()' on a null object reference
    at com.fyp.fypfoodbank.Activities.iFoodSharedActivity.onStart(iFoodSharedActivity.java:125)
    at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1392)
    at android.app.Activity.performStart(Activity.java:7260)
    at android.app.ActivityThread.handleStartActivity(ActivityThread.java:3009)
    at android.app.servertransaction.TransactionExecutor.performlifecycleSequence(TransactionExecutor.java:180)
    at android.app.servertransaction.TransactionExecutor.cycletoPath(TransactionExecutor.java:165)
    at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:142)
    at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:70)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1840)
    at android.os.Handler.dispatchMessage(Handler.java:106)
    at android.os.Looper.loop(Looper.java:207)
    at android.app.ActivityThread.main(ActivityThread.java:6878)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:547)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:876)

解决方法

您想通过OnQueryTextListener向您的SearchView添加setOnQueryTextListener()，每次输入字符串更改时都会调用onQueryTextChange。