即时聊天APP - MainActivity

Posted 2021-02-06 Joker

主活动包含三个Fragment，分别是会话、联系人和设置，初始布局隐藏所有碎片，然后把应该显示的显示出来：

//隐藏所有Fragment
private void hideAll(){
    FragmentManager fm = getFragmentManager();
    FragmentTransaction ft = fm.beginTransaction();
    ft.hide(first)
            .hide(second)
            .hide(third)
            .commit();
}
//初始化布局
private void init() {
    textView = findViewById(R.id.common_actionbar);
    textView.setOnClickListener(this);
    textView.setText("会话");
}
//初始化Fragment
private void initFragment() {
    FragmentManager fm = getFragmentManager();
    FragmentTransaction ft = fm.beginTransaction();
    first = new Conversationlist();
    second = new Friends();
    third = new My();
    ft.add(R.id.fragment,first);
    ft.add(R.id.fragment,second);
    ft.add(R.id.fragment,third);
    hideAll();
    //判断当前显示界面
    if(Tips.current == 0 || Tips.current == 1){
        ft.show(first);
        textView.setText("会话");
    }else if(Tips.current == 2){
        ft.show(second);
        textView.setText("联系人");
    }else {
        ft.show(third);
        textView.setText("设置");
    }
    ft.commit();
}  

接下来连接服务器，这里我放置了一个线程，每隔1秒检查检查一次是否连接成功：

//连接服务器
private void connect() {
    //检查网络连接
    if(!NetWork.isNetConnection(this)){
        Toast.makeText(this,"无网络连接！",Toast.LENGTH_SHORT).show();
        isConnect = false;
    }else{
        //每秒检查是否连接
        Timer timer = new Timer();
        timer.schedule(new TimerTask() {
            @Override
            public void run() {
                if(!isConnected())
                    isConnect = false;
                else
                    isConnect = true;
            }
        }, 300,1000);
        try {
            if (!isConnect) {
                if (Tips.MainActivity_fail == 0) {
                    Toast.makeText(MainActivity.this, "服务器连接失败！正在重试...", Toast.LENGTH_SHORT).show();
                    Tips.MainActivity_fail = 1;
                    Tips.MainActivity_success = 0;
                }
                BmobIM.connect(MyUser.getUni(), new ConnectListener() {
                    @Override
                    public void done(String s, BmobException e) {
                        if (e == null) {
                            isConnect = true;
                            retry = 0;
                            if (Tips.MainActivity_success == 0) {
                                Toast.makeText(MainActivity.this, "服务器连接成功！", Toast.LENGTH_SHORT).show();
                                Tips.MainActivity_success = 1;
                                Tips.MainActivity_fail = 0;
                            }
                        }else {
                            if (retry == 0)
                                if (Tips.MainActivity_fail == 0) {
                                    Toast.makeText(MainActivity.this, "服务器连接失败！正在重试...", Toast.LENGTH_SHORT).show();
                                    Tips.MainActivity_fail = 1;
                                    Tips.MainActivity_success = 0;
                                } else
                                    retry++;
                            connect();
                        }
                    }
                });
            }
        }catch (Exception e){}
    }
}  

这里是判断是否连接的代码：

//判断是否连接
private boolean isConnected(){
    boolean IsCon = false;
    try {
        String mg = BmobIM.getInstance().getCurrentStatus().getMsg();
        if(mg.equals("connected"))
            IsCon = true;
    }catch (Exception e){
        IsCon = false;
    }
    return IsCon;
}  

这里是发送自定义广播的代码，使用EventBus来触发事件：

//发送广播
@Subscribe(threadMode = ThreadMode.MAIN)
public void onMessageEvent(cn.edu.sau.joker.MessageEvent event) {
    Intent intent = new Intent("cn.edu.sau.action.MESSAGE");
    intent.putExtra("msg",event.message);
    sendBroadcast(intent);
}  

下面是退出代码，上面的部分是用户在点击退出的时候会finish掉此Activity，下面时用户点击两次返回键finish当前活动退出：

//销毁活动
@Override
protected void onNewIntent(Intent intent){
    super.onNewIntent(intent);
    if (intent != null) {
        boolean isExit = intent.getBooleanExtra(TAG_EXIT, false);
        if (isExit) {
            this.finish();
        }
    }
}
//连续按两次返回键就退出
@Override
public void onBackPressed() {
    // TODO Auto-generated method stub
    if (firstTime + 2000 > System.currentTimeMillis()) {
        super.onBackPressed();
    } else {
        Toast.makeText(this,"再按一次退出程序",Toast.LENGTH_SHORT).show();
        //     Toa("再按一次退出程序");
    }
    firstTime = System.currentTimeMillis();
}  

另外，在使用EventBus时要进行注册和注销：

//注册订阅者
    EventBus.getDefault().register(this);
// 注销订阅者
    EventBus.getDefault().unregister(this);