java在第二个活动的recyclerview中显示单词

Question

我正在尝试显示从第二个活动到我的主要活动的一个单词，这是一个包含textview项的回收器视图

我已经创建了我的适配器，我假设它可以正常工作唯一的问题是，一旦我启动浮动按钮访问我的显示字活动，它就不会显示在主活动上，我做错了什么，我是Android新手

我的适配器：

public class RoomAdapter extends RecyclerView.Adapter<RoomAdapter.RoomViewHolder> {

private List <RoomPojo> word;


public RoomAdapter(List <RoomPojo> word1){
    this.word = word1;

}
    @NonNull

    @Override
    public RoomViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {

        View layoutInflater = LayoutInflater.from(parent.getContext()).inflate(R.layout.word_item,parent,false);

        return new RoomViewHolder(layoutInflater);
    }

    @Override
    public void onBindViewHolder(@NonNull RoomViewHolder holder, int position) {

        holder.wordTextView.setText(word.get(position).getWord());
    }

    @Override
    public int getItemCount() {
        return word.size();
    }

    public class RoomViewHolder extends RecyclerView.ViewHolder{

        private TextView wordTextView;
        public RoomViewHolder(View itemView) {
            super(itemView);

            wordTextView = itemView.findViewById(R.id.display_word);

        }
    }
}

以下是我的主要活动：

public class MainActivity extends AppCompatActivity {


    private  RoomAdapter roomAdapter;
    public static final int NEW_WORD_ACTIVITY_REQUEST_CODE = 1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        RecyclerView recyclerView = findViewById(R.id.rv_word);

        recyclerView.setAdapter(roomAdapter);
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(linearLayoutManager);

        FloatingActionButton floatingActionButton = findViewById(R.id.fab);
        floatingActionButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(getApplicationContext(), DisplayWord.class);
                String word = getIntent().getStringExtra(DisplayWord.EXTRA_KEY);
                startActivityForResult(intent,NEW_WORD_ACTIVITY_REQUEST_CODE);
            }
        });
    }



}

这是我的显示字，它有一个按钮和一个编辑文本，应该只需要一个字符串

public class DisplayWord extends AppCompatActivity {

    public static final String EXTRA_KEY = "key";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_display_word);

        final EditText editText = findViewById(R.id.word_edit_text);
        Button button = findViewById(R.id.word_button);

        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent replyIntent = new Intent();
                if(TextUtils.isEmpty(editText.getText())){
                    setResult(RESULT_CANCELED, replyIntent);
                }else {
                String word = editText.getText().toString();
                replyIntent.putExtra(EXTRA_KEY,word);


                }

                finish();
            }
        });


    }
}

梅因。xml

<?xml version="1.0" encoding="utf-8"?>
<安卓.support.constraint.ConstraintLayout xmlns:安卓="http://schemas.安卓.com/apk/res/安卓"
    xmlns:app="http://schemas.安卓.com/apk/res-auto"
    xmlns:tools="http://schemas.安卓.com/tools"
    安卓:layout_width="match_parent"
    安卓:layout_height="match_parent"
    tools:context=".MainActivity">

    <安卓.support.v7.widget.RecyclerView
        安卓:id="@+id/rv_word"
        安卓:layout_width="368dp"
        安卓:layout_height="433dp"
        安卓:layout_marginLeft="8dp"
        安卓:layout_marginStart="8dp"
        安卓:layout_marginTop="8dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <安卓.support.design.widget.FloatingActionButton
        安卓:id="@+id/fab"
        安卓:layout_width="wrap_content"
        安卓:layout_height="wrap_content"
        安卓:layout_gravity="bottom|end"
        安卓:layout_marginLeft="328dp"
        安卓:layout_marginStart="328dp"
        安卓:layout_marginTop="12dp"
        安卓:src="@drawable/ic_add_black_24dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/rv_word" />
</安卓.support.constraint.ConstraintLayout>

Answer 1

您的代码应该如下所示：

       button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent replyIntent = new Intent();
            if(TextUtils.isEmpty(editText.getText())){
                setResult(RESULT_CANCELED, replyIntent);
            }else {
            String word = editText.getText().toString();
            replyIntent.putExtra(EXTRA_KEY,word);
            setResult(RESULT_OK, replyIntent); //missing
            }

            finish();
        }
    });

然后在MainActivity中处理它。爪哇

    @Override
      protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    try {
        super.onActivityResult(requestCode, resultCode, data);

        if (requestCode == REQUEST_CODE  && resultCode  == RESULT_OK) {

            String requiredValue = data.getStringExtra(DisplayWord.EXTRA_KEY);
        }
    } catch (Exception ex) {
        Toast.makeText(Activity.this, ex.toString(),
                Toast.LENGTH_SHORT).show();
    }

}