如何实现账号强制下线

强制用户下线这个功能大家应该见过很多了，到底怎么实现呢现在我们一起来做一做

建立activity的管理类

  public class ActivityCollector
  {
    public static List<Activity> activityList = new ArrayList<>();

    public static void addActivity(Activity activity)
    {
        activityList.add(activity);
    }

    public static void removeActivity(Activity activity)
    {
        activityList.remove(activity);
    }

    public static void finshAllActivity()
    {
        for(Activity activity : activityList)
        {
            if (!activity.isFinishing())
            {
                activity.finish();
            }
        }
    }
}

建立基本的activity,BaseActivity,所有的Activity都继承它，在oncreate , onResume,onDestroy添加以下代码，会注意到这里注册了一个广播，之所以要在BaseActivity里面注册是是因为以后的每个Activity都会继承BaseActivity,这个就可以保证每个界面都可以接收这个广播

  public class BaseActivity extends AppCompatActivity
{
    private ForceOffineReceiver forceOffineReceiver;
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        ActivityCollector.addActivity(this);
    }

    @Override
    protected void onResume()
    {
        super.onResume();
        IntentFilter intentFilter = new IntentFilter();
        intentFilter.addAction("com.zz.mybreadcast.FORCE_OFFINE");
        forceOffineReceiver = new ForceOffineReceiver();
        registerReceiver(forceOffineReceiver , intentFilter);
    }

    @Override
    protected void onDestroy()
    {
        super.onDestroy();
        ActivityCollector.removeActivity(this);
        if (forceOffineReceiver != null)
        {
            unregisterReceiver(forceOffineReceiver);
        }
    }
}

建立一个登陆的界面，界面很简单，界面我就不贴了

1511504182(1).png

  public class LoginActivity extends BaseActivity
{
    private EditText login_view;
    private EditText password_view;
    private Button login_button;
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        initView();
        initData();
    }

    private void initView()
    {
        login_view = findViewById(R.id.login_view);
        password_view = findViewById(R.id.password_view);
        login_button = findViewById(R.id.login_button);
    }

    private void initData()
    {
        login_button.setOnClickListener(v ->
        {
            String loginStr = login_view.getText().toString().trim();
            String passwordStr = password_view.getText().toString().trim();
            if(loginStr.equals("admin") && passwordStr.equals("123456"))
            {
                startActivity(new Intent(this , MainActivity.class));
                finish();
            }
            else
            {
                Toast.makeText(LoginActivity.this , "账号或者密码错误!" , Toast.LENGTH_LONG);
            }
        });
    }


}

建立广播，代码如下

public class ForceOffineReceiver extends BroadcastReceiver
{

    @Override
    public void onReceive(Context context, Intent intent)
    {
        AlertDialog.Builder builder = new AlertDialog.Builder(context);
        builder.setTitle("提示");
        builder.setCancelable(false);
        builder.setMessage("您的账号在另外一台手机已经登录！");
        builder.setPositiveButton("确定" , new DialogInterface.OnClickListener(){
            @Override
            public void onClick(DialogInterface dialog, int which)
            {
                ActivityCollector.finshAllActivity();
                context.startActivity(new Intent(context , LoginActivity.class));
            }
        });
        builder.show();
    }
}

最后是MainActivity，这个类里面只需模仿发送下线广播就行

public class MainActivity extends BaseActivity
{
    private Button main_button;
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        main_button = findViewById(R.id.main_button);
        // lambda表达式
        main_button.setOnClickListener(v -> {
            Intent intent = new Intent("com.zz.mybreadcast.FORCE_OFFINE");
            sendBroadcast(intent);
       });
    }
}