EChat(简易聊天项目)三、聊天界面UI实现

一、添加部分控件完善登入过程

① 设计应用登录界面加入ImageView

在login_layout.xml中加入以下代码

 

② 设计应用登录界面登录时加入ProgresDialog

修改LoginActivity中代码

...

login.setOnClickListener(new View.OnClickListener(){
    public void onClick(View v) {

...

ProgressDialog progressDialog = new ProgressDialog(LoginActivity.this);
    progressDialog.setTitle("正在登陆");
    progressDialog.setMessage("Loading...");
    progressDialog.setCancelable(true);
    progressDialog.show();
    //创建Intent对象，传入源Activity和目的Activity的类对象
    Intent intent = new Intent(LoginActivity.this, SuccessActivity.class);
    //启动Activity
    startActivity(intent);

    }
});     .

 

③ 设计注册页面的注册确认加上AlertDialog

添加RegistActivity处对注册确定按钮的代码

yes.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        AlertDialog.Builder dialog = new AlertDialog.Builder(RegistActivity.this);
        dialog.setTitle("Attention:");
        dialog.setMessage("确认要进行注册么");
        dialog.setCancelable(false);
        dialog.setPositiveButton("OK", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                EditText username = (EditText)findViewById(R.id.username);
                EditText password = (EditText)findViewById(R.id.password);

                //判断用户注册是否输入了密码和用户名
                //首先学会如何判断EditText中内容为空，要包含trim（去掉首部空格）
                if (username.getText().length()==0||password.getText().length() == 0){
                    Toast.makeText(RegistActivity.this,"用户名和密码不能为空" , Toast.LENGTH_SHORT).show();
                }else {

                    //判断是否已经注册了相同用户名
                    boolean flag = false;
                    List users = DataSupport.findAll(User.class);
                    for(User user : users){
                        if(username.equals(user.getUsername())){
                            flag = true;
                        }
                    }

                    if(flag) {
                        Toast.makeText(RegistActivity.this,"该用户名已经注册",Toast.LENGTH_SHORT).show();
                    }else {
                        //新建LitePal数据库
                        Connector.getDatabase();
                        User user = new User();
                        String strusername=username.getText().toString();
                        String strpassword=password.getText().toString();
                        //存储用户名密码
                        user.setUsername(strusername);
                        user.setPassword(strpassword);
                        user.save();
                        Toast.makeText(RegistActivity.this,"创建用户成功",Toast.LENGTH_SHORT).show();
                        Intent intent = new Intent(RegistActivity.this,SuccessActivity.class);
                        startActivity(intent);
                    }
                }
            }
        });
        dialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
            }
        });
        dialog.show();
    }
});

 

二、聊天界面活动使用之前的SuccessActivity，当登录后来到好友界面FriendActivity，当点击某一同学时会跳转到制作的聊天界面

①首先在app/build.gradle中添加依赖库

compile 'com.android.support:recyclerview-v7:25.3.1'

②编写主界面，修改success_layout.xml中的代码

③ 定义消息的实体类，新建Msg

public class Msg {
    public static final int TYPE_RECEIVED = 0;
    public static final int TYPE_SENT = 1;
    private String content;
    private int type;

    public Msg(String content,int type){
        this.content = content;
        this.type = type;
    }
    public String getContent(){
        return content;
    }
    public int getType(){
        return type;
    }

}

④ 编写RecyclerView子项的布局，新建msg_item.xml

⑤ 创建RecyclerView的适配器类，新建类MsgAdapter

public class MsgAdapter extends RecyclerView.Adapter{
    private List mMsgList;

    static class ViewHolder extends RecyclerView.ViewHolder{
        LinearLayout leftLayout;
        LinearLayout rightLayout;
        TextView leftMsg;
        TextView rightMsg;

        public ViewHolder(View view){
            super(view);
            leftLayout = (LinearLayout)view.findViewById(R.id.left_layout);
            rightLayout = (LinearLayout)view.findViewById(R.id.right_layout);
            leftMsg = (TextView)view.findViewById(R.id.left_msg);
            rightMsg = (TextView)view.findViewById(R.id.right_msg);
        }
    }
    public MsgAdapter(List msgList){
        mMsgList = msgList;
    }
    @Override
    public MsgAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.msg_item,parent,false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(MsgAdapter.ViewHolder holder, int position) {
        Msg msg = mMsgList.get(position);
        if(msg.getType() == Msg.TYPE_RECEIVED){
            //如果是收到的消息，则显示左边的消息布局，将右边的消息布局隐藏
            holder.leftLayout.setVisibility(View.VISIBLE);
            holder.rightLayout.setVisibility(View.GONE);
            holder.leftMsg.setText(msg.getContent());
        }else if (msg.getType() == Msg.TYPE_SENT){
            //如果是发出的消息，则显示右边的消息布局，将左边的消息布局隐藏
            holder.rightLayout.setVisibility(View.VISIBLE);
            holder.leftLayout.setVisibility(View.GONE);
            holder.rightMsg.setText(msg.getContent());
        }
    }

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

⑥最后修改SuccessActivity中的代码，为RecyclerView初始化一些数据，并给发送按钮加入事件响应

public class SuccessActivity extends AppCompatActivity {

    private List msgList = new ArrayList<>();
    private EditText inputText;
    private Button send;
    private RecyclerView msgRecyclerView;
    private MsgAdapter adapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //将正在创建的活动添加到活动管理器中
        ActivityCollector.addActivity(this);
        setContentView(R.layout.success__layout);

        initMsg();//初始化消息数据
        inputText = (EditText) findViewById(R.id.input_text);
        send = (Button) findViewById(R.id.send);
        msgRecyclerView = (RecyclerView) findViewById(R.id.msg_recycle_view);
        LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        msgRecyclerView.setLayoutManager(layoutManager);
        adapter = new MsgAdapter(msgList);
        msgRecyclerView.setAdapter(adapter);
        send.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String content = inputText.getText().toString();
                if (!"".equals(content)){
                    Msg msg = new Msg(content,Msg.TYPE_SENT);
                    msgList.add(msg);
                    adapter.notifyItemInserted(msgList.size() - 1);//当有新消息时，刷新RecyclerView中的显示
                    msgRecyclerView.scrollToPosition(msgList.size() - 1);//将RecyclerView定位到最后一行
                    inputText.setText("");//清空输入框中的内容
                }
            }
        });

    }

    private void initMsg() {
        Msg msg1 = new Msg("Hello guy.", Msg.TYPE_RECEIVED);
        msgList.add(msg1);
        Msg msg2 = new Msg("Hello.Who is that?", Msg.TYPE_SENT);
        msgList.add(msg2);
        Msg msg3 = new Msg("This is Tom. Nice talking to you.",Msg.TYPE_RECEIVED);
        msgList.add(msg3);
    }


    //表明一个要销毁的活动从活动管理器里移除
    @Override
    protected void onDestroy() {
        super.onDestroy();
        ActivityCollector.removeActivity(this);
    }

    //创建Option菜单
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main,menu);
        return true;
    }
    //定义菜单响应事件
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()){
            case R.id.exit://当点击了退出时，退出程序
                ActivityCollector.finishAll();
                android.os.Process.killProcess(android.os.Process.myPid());
                break;
            default:
        }
        return true;
    }
}

效果如图