Java 如何声明ArrayList？（预期标识符）

我正忙着用我在网上找到的教程在Android上构建一个基本的聊天应用程序。我复制了他们在示例中使用的代码，到目前为止没有任何问题。现在我得到以下错误：

C:\Users\Brian\AndroidStudioProjects\ChatApp\app\src\main\java\com\example\brian\chatapp\ChatAdapter.java
Error:(20, 14) error: <identifier> expected
Error:(20, 17) error: <identifier> expected
Error:(20, 29) error: <identifier> expected
Error:(20, 32) error: <identifier> expected
Error:(20, 49) error: <identifier> expected
Error:(22, 52) error: <identifier> expected
Error:(22, 53) error: ';' expected
Error:(22, 67) error: <identifier> expected
Error:(22, 70) error: <identifier> expected
Error:(22, 76) error: <identifier> expected
C:\Users\Brian\AndroidStudioProjects\ChatApp\app\src\main\java\com\example\brian\fragments\Chats.java
Error:(26, 28) error: <identifier> expected
Error:(26, 31) error: <identifier> expected
Error:(26, 43) error: <identifier> expected
Error:(26, 46) error: <identifier> expected
Error:(26, 56) error: <identifier> expected
Error:(47, 33) error: '(' or '[' expected
Error:(47, 48) error: not a statement
Error:(47, 54) error: lambda expressions are not supported in -source 1.7
(use -source 8 or higher to enable lambda expressions)
:app:compileDebugJavaWithJavac FAILED
Error:Execution failed for task ':app:compileDebugJavaWithJavac'.
> Compilation failed; see the compiler error output for details.
Information:BUILD FAILED
Information:Total time: 1.069 secs
Information:19 errors
Information:0 warnings
Information:See complete output in console

任何帮助都将不胜感激！以下是我正在使用的教程的链接：

：编辑：

它似乎已经用@krzyk的方法解决了。但是现在我在Chats.java类中遇到了另一个问题，下面是代码：

package com.example.brian.chatapp;

import java.util.ArrayList;

import android.app.Activity;
import android.content.Context;
import android.graphics.Color;
import android.util.Log;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.LinearLayout;
import android.widget.TextView;

public class ChatAdapter extends BaseAdapter {

private static LayoutInflater inflater = null;

ArrayList<
ChatMessage>
chatMessageList;

public ChatAdapter(Activity activity, ArrayList<ChatMessage> list) {
    chatMessageList = list;
    inflater = (LayoutInflater) activity
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

}

@Override
public int getCount() {
    return chatMessageList.size();
}

@Override
public Object getItem(int position) {
    return position;
}

@Override
public long getItemId(int position) {
    return position;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    ChatMessage message = (ChatMessage) chatMessageList.get(position);
    View vi = convertView;
    if (convertView == null)
        vi = inflater.inflate(R.layout.chatbubble, null);

    TextView msg = (TextView) vi.findViewById(R.id.message_text);
    msg.setText(message.body);
    LinearLayout layout = (LinearLayout) vi
            .findViewById(R.id.bubble_layout);
    LinearLayout parent_layout = (LinearLayout) vi
            .findViewById(R.id.bubble_layout_parent);

    // if message is mine then align to right
    if (message.isMine) {
        layout.setBackgroundResource(R.drawable.bubble2);
        parent_layout.setGravity(Gravity.RIGHT);
    }
    // If not mine then align to left
    else {
        layout.setBackgroundResource(R.drawable.bubble1);
        parent_layout.setGravity(Gravity.LEFT);
    }
    msg.setTextColor(Color.BLACK);
    return vi;
}

public void add(ChatMessage object) {
    chatMessageList.add(object);
}
}

package com.example.brian.fragments;

import java.util.ArrayList;
import java.util.Random;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.app.ActionBarActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.ListView;

import com.example.brian.chatapp.ChatAdapter;
import com.example.brian.chatapp.ChatMessage;
import com.example.brian.chatapp.CommonMethods;
import com.example.brian.chatapp.R;

public class Chats extends Fragment implements OnClickListener {

private EditText msg_edittext;
private String user1 = "khushi", user2 = "khushi1";
private Random random;
public static ArrayList<ChatMessage> chatlist;
public static ChatAdapter chatAdapter;
ListView msgListView;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.chat_layout, container, false);
    random = new Random();
    ((ActionBarActivity) getActivity()).getSupportActionBar().setTitle(
            "Chats");
    msg_edittext = (EditText) view.findViewById(R.id.messageEditText);
    msgListView = (ListView) view.findViewById(R.id.msgListView);
    ImageButton sendButton = (ImageButton) view
            .findViewById(R.id.sendMessageButton);
    sendButton.setOnClickListener(this);

    // ----Set autoscroll of listview when a new message arrives----//
    msgListView.setTranscriptMode(ListView.TRANSCRIPT_MODE_ALWAYS_SCROLL);
    msgListView.setStackFromBottom(true);

    chatlist = new ArrayList<ChatMessage>();
    chatAdapter = new ChatAdapter(getActivity(), chatlist);
    msgListView.setAdapter(chatAdapter);
    return view;
}

@Override
public void onSaveInstanceState(Bundle outState) {
}

public void sendTextMessage(View v) {
    String message = msg_edittext.getEditableText().toString();
    if (!message.equalsIgnoreCase("")) {
        final ChatMessage chatMessage = new ChatMessage(user1, user2,
                message, "" + random.nextInt(1000), true);
        chatMessage.setMsgID();
        chatMessage.body = message;
        chatMessage.Date = CommonMethods.getCurrentDate();
        chatMessage.Time = CommonMethods.getCurrentTime();
        msg_edittext.setText("");
        chatAdapter.add(chatMessage);
        chatAdapter.notifyDataSetChanged();
    }
}

@Override
public void onClick(View v) {
    switch (v.getId()) {
        case R.id.sendMessageButton:
            sendTextMessage(v);

    }
}

}

---

您需要删除<和>：

ArrayList<ChatMessage> chatMessageList;

public ChatAdapter(Activity activity, ArrayList<ChatMessage> list) {
    chatMessageList = list;
    inflater = (LayoutInflater) activity
        .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

}

arraylistchatmessagelist；
公共聊天适配器（活动，ArrayList列表）{
chatMessageList=list；
充气器=（充气器）活动
.getSystemService（上下文布局\充气机\服务）；
}

更改：

ArrayList<
ChatMessage>
chatMessageList;

public ChatAdapter(Activity activity, ArrayList<ChatMessage> list) {

致：

arraylistchatmessagelist；
公共聊天适配器（活动，ArrayList列表）{

---

如果你的教程显示了像

或

这样的html实体，那么你的教程写得很糟糕。如果你遇到它们，就把

改成

为什么你的代码中有

和

呢？我不太确定，这正是怎么回事是教程中使用的示例。如我所说，我是ArrayS的noob教程在将其保存到DB时似乎已中断（在内容中转义字符，然后不取消其转义）.

ArrayListChatMessage chatMessageList；

应该是

ArrayList chatMessageList；

你的答案对我真的很有帮助，我现在编辑了这个问题，但我收到了另一个错误。我认为作者在使用自己的代码时犯了很多错误。@Brian不要编辑你的问题，改变它们，请询问其他问题一个只是创建一个全新的问题（这不是一个论坛）。好吧，我对StAcdPoad是相当新的。我仍然不知道问题本身是如何工作的，事实上，XD发现了我以前的问题的难点，如何给它添加代码。不用担心，这里每个人都是新手。（您只能选择一个被接受的答案）并且如果您发现其中许多答案足够好，您也可以向上投票多个答案。谢谢，现在让我等待一段时间，直到我可以再次询问xD是否有办法在90分钟的等待时间内工作？

ArrayList<
ChatMessage>
chatMessageList;

public ChatAdapter(Activity activity, ArrayList<ChatMessage> list) {

ArrayList<ChatMessage> chatMessageList;

public ChatAdapter(Activity activity, ArrayList<ChatMessage> list) {