移动开发实验二

实验目的：

在任一页面实现列表效果，并在RecycleView的每个item添加点击跳转功能，跳转后显示新的页面

开发技术：

开发工具：Android Studio

版本：API24 Android 7.0

设计流程：

在实验一的基础上增加了 MessageAdapter.java 和 SendMessageActivity.java 以及一些Layout页面(如item_message.xml)

新增JAVA代码

MessageAdapter.java

public class Myadapter extends RecyclerView.Adapter<Myadapter.Myholder> {
    Context context1;
    List list1;
    String[] tabTitles = new String[]{"My File", "FB","DXY","ZYJ","SZF","JZC"};
    int[] avatars =new int[]{R.drawable.file, R.drawable.addrbook_2_24dp, R.drawable.message_1_24dp}; // 你的头像资源ID
    public Myadapter(Context context, List list) {
        context1 = context;
        list1 = list;
    }

    @NonNull
    @Override
    public Myholder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(context1).inflate(R.layout.item_msg, parent, false);
        return new Myholder(view);
    }

    @SuppressLint("SetTextI18n")
    @Override
    public void onBindViewHolder(@NonNull Myholder holder, @SuppressLint("RecyclerView") int position) {
        String data = (String) list1.get(position);
        if (position < tabTitles.length) {
            holder.msgName.setText(tabTitles[position]); // 设置标题
        } else {
            holder.msgName.setText("Default Title"); // 如果position大于tabTitles的长度，设置一个默认标题
        }
        holder.msgContent.setText(data); // 设置内容
        if (position < avatars.length) {
            holder.avatar.setImageResource(avatars[position]); // 设置头像
        } else {
            holder.avatar.setImageResource(R.drawable.discover_3_24dp); // 如果position大于avatars的长度，设置一个默认头像
        }

        holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(context1, SendMessageActivity.class);
                intent.putExtra("username", tabTitles[position]);
                context1.startActivity(intent);
            }
        });
    }

    @Override
    public int getItemCount() {
        return list1.size();
    }

    public class Myholder extends RecyclerView.ViewHolder {
        TextView msgName;
        TextView msgContent;
        ImageView avatar; // 头像
        public Myholder(@NonNull View itemView) {
            super(itemView);
            msgName = itemView.findViewById(R.id.msgName1);
            msgContent = itemView.findViewById(R.id.msgContent1);
            avatar = itemView.findViewById(R.id.avatar);
        }
    }
}

SendMessageActivity.java

public class SendMessageActivity extends AppCompatActivity {
    private TextView textViewUsername;
    private RecyclerView recyclerViewMessages;
    private EditText editTextMessage;
    private Button buttonSend;
    String username;
    private List<String> messages = new ArrayList<>();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_send_message1);
        textViewUsername = this.findViewById(R.id.textViewUsername);
        recyclerViewMessages = this.findViewById(R.id.recyclerViewMessages);
        editTextMessage = this.findViewById(R.id.editTextMessage);
        buttonSend = this.findViewById(R.id.buttonSend);
        username = this.getIntent().getStringExtra("username");
        // 设置用户名
        textViewUsername.setText(username);
        // 设置聊天信息的适配器
        MessageAdapter adapter = new MessageAdapter(this, messages);
        recyclerViewMessages.setAdapter(adapter);
        buttonSend.setOnClickListener(new View.OnClickListener() {
            @SuppressLint("NotifyDataSetChanged")
            @Override
            public void onClick(View v) {
                String message = editTextMessage.getText().toString();
                if (!message.isEmpty()) {
                    // 添加信息到聊天信息列表
                    messages.add(message);
                    adapter.notifyDataSetChanged();
                    // 清空输入框
                    editTextMessage.setText("");
                    Toast.makeText(SendMessageActivity.this, "信息已发送: " + message, Toast.LENGTH_SHORT).show();
                } else {
                    Toast.makeText(SendMessageActivity.this, "请输入信息", Toast.LENGTH_SHORT).show();
                }
            }
        });
    }

新增布局Layout

2023-11-11T06:55:57.png

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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/onechat"
    android:layout_width="match_parent"
    android:layout_height="70dp">

    <ImageView
        android:id="@+id/avatar"
        android:layout_width="60dp"
        android:layout_height="60dp"
        android:src="@drawable/addrbook_2_24dp" /> <!-- 默认头像 -->

    <LinearLayout
        android:layout_width="304dp"
        android:layout_height="match_parent"
        android:layout_weight="1"
        android:orientation="vertical">

        <TextView
            android:id="@+id/msgName1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="20dp"
            android:text="标题"
            android:textColor="@color/black" />

        <TextView
            android:id="@+id/msgContent1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="9dp"
            android:text="内容"
            android:textSize="15sp" />

    </LinearLayout>

</LinearLayout>