Android uses broadcast to implement forced offline function ———— first line of code

This article has participated in the activity of “New person creation Ceremony”, and started the road of digging gold creation together.

show

Example download

Download.csdn.net/download/lj…

Train of thought

1. First we need to use broadcast, send a broadcast, to say that we need to force offline 2. You need to register a broadcast, and when that broadcast is received, a dialog box pops up, then finish() all activities, and jump to LoginActivity. But now we don’t know which activity will receive this broadcast, so we need to define a BaseActivity. The broadcast receiver is then registered and destroyed in BaseActivity

Code implementation

1. Tool class ActivityCollector

import android.app.Activity

object ActivityCollector {
    private val activities = ArrayList<Activity>()
    / / add
    fun addActivity(activity: Activity) {
        activities.add(activity)
    }
    / / remove
    fun removeActivity(activity: Activity) {
        activities.remove(activity)
    }
    / / finish all
    fun finishAll(a) {
        for (activity in activities) {
            if(! activity.isFinishing) { activity.finish() } } activities.clear() } }Copy the code

2. BaseActivity

import android.content.*
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import androidx.appcompat.app.AlertDialog
import com.example.kotlindemo4.LoginActivity

open class BaseActivity : AppCompatActivity() {

    private lateinit var receiver: OfflineReceiver

    override fun onCreate(savedInstanceState: Bundle?). {
        super.onCreate(savedInstanceState)
        ActivityCollector.addActivity(this)}/** * Registered in the onResume method, meaning that only activities at the top of the stack should be registered */
    override fun onResume(a) {
        super.onResume()
        val intentFilter = IntentFilter("com.example.bddemo.OFFLINE")
        receiver = OfflineReceiver()
        registerReceiver(receiver, intentFilter)
    }
    /** * When the activity exits the top of the stack, the broadcast is not needed, so cancel */ in onPause
    override fun onPause(a) {
        super.onPause()
        unregisterReceiver(receiver)
    }

    override fun onDestroy(a) {
        super.onDestroy()
        ActivityCollector.removeActivity(this)}inner class OfflineReceiver : BroadcastReceiver() {
        override fun onReceive(context: Context? , intent:Intent?). {

            if(context ! =null) {
                AlertDialog.Builder(context).apply {
                    setTitle("Tip")
                    setMessage("Your account is logged in elsewhere. Please log in again.")
                    setCancelable(false)
                    setPositiveButton("Sure") { _, _ ->
                        ActivityCollector.finishAll()
                        val i = Intent(context, LoginActivity::class.java)
                        context.startActivity(i)

                    }
                    create()
                    show()
                }
            }
        }
    }
}

Copy the code

3. MainActivity

import android.content.Intent
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import com.example.bddemo.BaseActivity
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : BaseActivity() {

    override fun onCreate(savedInstanceState: Bundle?). {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        btn_out.setOnClickListener {
            val intent = Intent("com.example.bddemo.OFFLINE")
            sendBroadcast(intent)
        }
    }
}
Copy the code