用kotlin实现简单的强制下线功能

强制下线是需要关闭所有的活动，先创建一个类来管理所有的活动。

class ActivityCollector {
    //var activities :MutableList<Activity>=MutableList<Activity>()
    companion object{
        val activities = ArrayList<Activity>()
        fun addActivity( activity:Activity){
            activities.add(activity)
        }
        fun removeActivity(activity:Activity){
            activities.remove(activity)
        }
        fun finsishAll(){
            for(activity:Activity in activities){
                if(!activity.isFinishing){
                    activity.finish()
                }
            }
            activities.clear()
        }
    }
}

然后建立一个所有活动的父类

open class BaseActivity : AppCompatActivity(){
    var activityCollector=ActivityCollector()
    lateinit var receiver:ForceOfflineReceiver
    override fun onCreate(savedInstanceState: Bundle?, persistentState: PersistableBundle?) {
        super.onCreate(savedInstanceState, persistentState)
        ActivityCollector.addActivity(this)
        //activityCollector.addActivity(this)
    }
    override fun onResume() {
        super.onResume()
        var inetnefilter:IntentFilter=IntentFilter()
        inetnefilter.addAction("FORCE_FOOLINE")
        receiver=ForceOfflineReceiver()
        registerReceiver(receiver,inetnefilter)
    }
    override fun onPause() {
        super.onPause()
        if(receiver!=null){
            unregisterReceiver(receiver)
           // receiver=null
        }
    }
    override fun onDestroy() {
        super.onDestroy()
        ActivityCollector.removeActivity(this)
    }
    open class ForceOfflineReceiver : BroadcastReceiver(){
        override fun onReceive(context: Context, intent: Intent?) {
            var builder :AlertDialog.Builder=AlertDialog.Builder(context)
            builder.setTitle("Warning")
            builder.setMessage("you are forced to be offline .please try to login again")
            builder.setCancelable(false)
            builder.setPositiveButton("ok",object :DialogInterface.OnClickListener{
                override fun onClick(dialog: DialogInterface?, which: Int) {
                    ActivityCollector.finsishAll()
                    var intent=Intent(context,LoginActivity::class.java)
                    context.startActivity(intent)
                }
            })
            builder.show()
        }
    }
}

建立一个登录的布局文件

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="60dp"
    android:orientation="horizontal">
    <TextView
        android:layout_width="90dp"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical"
        android:textSize="18sp"
        android:text="account:"
        />
    <EditText
        android:id="@+id/account"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:layout_gravity="center_vertical"
        />
</LinearLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="60dp"
        android:orientation="horizontal">
        <TextView
            android:layout_width="90dp"
            android:layout_height="wrap_content"
            android:layout_gravity="center_vertical"
            android:textSize="18sp"
            android:text="password:"
            />
        <EditText
            android:id="@+id/password"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:layout_gravity="center_vertical"
            android:inputType="textPassword"
            />
    </LinearLayout>
    <Button
        android:id="@+id/login"
        android:layout_width="match_parent"
        android:layout_height="60dp"
        android:text="Login"
        />
</LinearLayout>

然后编写一个登录的活动，这里写了一个简单的登录，密码正确的话就进入主页面，否则给出提示。

class LoginActivity:BaseActivity(){
      lateinit  var accountEdid:EditText
      lateinit var passwordEdit :EditText
       lateinit var login:Button
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.login)
        accountEdid=findViewById(R.id.account)
        passwordEdit=findViewById(R.id.password)
        login=findViewById(R.id.login)
        login.setOnClickListener(View.OnClickListener {
            var account =accountEdid.text.toString()
            var password=passwordEdit.text.toString()
            if(account.equals("admin")&&password.equals("123")){
                var intent:Intent=Intent(this, MainActivity::class.java)
                startActivity(intent)
                finish()
            }else{
                Toast.makeText(this,"账号或密码错误",Toast.LENGTH_SHORT).show()
            }
        })
    }
}

然后修改一下mainactivity的代码

class MainActivity : BaseActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        var forceOffline :Button =findViewById(R.id.force_offline)
        forceOffline.setOnClickListener(View.OnClickListener {
            var intent:Intent=Intent("FORCE_FOOLINE")
            sendBroadcast(intent)
        })
    }
}

最后对AndroidManifest.xml修改，把主活动设置更换一下。

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name=".MainActivity">
    </activity>
    <activity android:name=".LoginActivity" android:launchMode="singleTask">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>