java - 在 android studio 中添加 textwatcher 后，我的 firebase RecyclerView 不显示任何内容

问题描述

我想要的实际上是一个搜索文本字段和一个循环视图和显示适配器，它基于搜索文本字段中的文本。下面的链接是我参考的代码。如何使用 TextWatcher 实现 firebase 回收器？

绑定视图

@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();
    }

错误显示

  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)

标签： javaandroidfirebaseandroid-recyclerviewtextwatcher

java - 在 android studio 中添加 textwatcher 后，我的 firebase RecyclerView 不显示任何内容

问题描述

解决方案

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