Kotlin学习笔记——BroadCast

#define 小毛驴 xml

收发广播

使用场景：Fragment想要向外传递信息

1. 在Fragment中发送广播

   class BlankFragment : Fragment() {
       var ctx:Context? = null
       var mPosition:Int = 0
       var mInageId:Int = 0
       var mDesc:String = ""
       var title:String = ""
   
       val colorNames = listOf<String>("红色","黄色","绿色","青色","蓝色")
       val colors = intArrayOf(Color.RED, Color.YELLOW, Color.GREEN, Color.CYAN, Color.BLUE)
       var mSeq:Int = 0
       override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
           ctx = activity
           if (arguments != null) {
               mPosition = arguments!!.getInt("position", 0)
               mInageId = arguments!!.getInt("image_id", 0)
               mDesc = arguments!!.getString("desc")
               title = arguments!!.getString("title")
           }
           val view = inflater.inflate(R.layout.show_info, container, false)
   
           view.findViewById<ImageView>(R.id.imageView).setImageResource(mInageId)
           view.findViewById<TextView>(R.id.textView).text = mDesc
           view.findViewById<Button>(R.id.se).setOnClickListener {
               ctx!!.selector("选择颜色", colorNames) {
                   mSeq = it
   
                   val intent = Intent(BlankFragment.EVENT)
                   intent.putExtra("seq", it)
                   intent.putExtra("color", colors[it])
                   ctx!!.sendBroadcast(intent)//发送广播
               }
           }
           return view
       }
   
       companion object {
           const val EVENT:String = "changeColor"//const，编译期常量
           fun newInstance(position:Int, image_id:Int, desc:String, title:String) : BlankFragment {
   
               val fragment = BlankFragment()
               val bundle = Bundle()
               bundle.putInt("position", position)
               bundle.putInt("image_id", image_id)
               bundle.putString("desc", desc)
               bundle.putString("title", title)
               fragment.arguments = bundle
               return fragment
           }
       }
   }

2. 在要接收广播的页面注册receiver

   class MainActivity : FragmentActivity(){
       private var BGChangeRecever:myBgChangeRecever? = null
       override fun onCreate(savedInstanceState: Bundle?) {
           super.onCreate(savedInstanceState)
           setContentView(R.layout.activity_main)
           var vp:ViewPager = findViewById(R.id.vp)
           var title: PagerTabStrip = findViewById(R.id.title)
   
           val pics = arrayOf(R.mipmap.basic, R.mipmap.close, R.mipmap.debug, R.mipmap.edit)
           val list:MutableList<itemInfo> = mutableListOf()
           for (i in pics.indices) {
               list.add(itemInfo((i+1).toString(), pics[i], ((i+1)*(i+1)).toString()))
           }
           vp.adapter = infoPagerAdapter(supportFragmentManager, list)
           vp.currentItem = 0
       }
   
       public override fun onStart() {
           super.onStart()
           BGChangeRecever = myBgChangeRecever()
   
           val filiter = IntentFilter(BlankFragment.EVENT)//广播过滤器，过滤掉参数以外的广播
           registerReceiver(BGChangeRecever,filiter)//开始时注册接收器
   
       }
   
       public override fun onStop() {
           unregisterReceiver(BGChangeRecever)//结束前注销接收器
           super.onStop()
       }
   
       private inner class myBgChangeRecever : BroadcastReceiver() {//广播接收器
           override fun onReceive(context: Context?, intent: Intent?) {//接收广播后执行的操作
               if (intent != null) {
                   val color = intent.getIntExtra("color", Color.GREEN)
                   textView2.setTextColor(color)
               }
           }
   
       }
   }

接收系统广播

静态注册

没学会

动态注册

class MainActivity : AppCompatActivity() {
    var receiver:broadCastRecever = broadCastRecever()
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
    }

    override fun onDestroy() {
        super.onDestroy()
        receiver.unRegiste()
    }

    override fun onStart() {
        super.onStart()
        receiver.registe(this)
    }

    inner class broadCastRecever : BroadcastReceiver() {
        private var isRegisted = false
        var allBroadCast = arrayOf(Intent.ACTION_TIME_TICK, Intent.ACTION_SCREEN_ON, Intent.ACTION_SCREEN_OFF)
        var registTo:Context? = null
        override fun onReceive(context: Context?, intent: Intent?) {
            text.append("收到：${(intent?.action?:"empty")}\n")
        }
        fun registe(context: Context) {
            if (!isRegisted) {
                var filter:IntentFilter = IntentFilter()
                for (item in allBroadCast) {
                    filter.addAction(item)
                }
                context.registerReceiver(this@broadCastRecever, filter)
                isRegisted = true
                registTo = context
            }
        }
        fun unRegiste() {
            if (isRegisted) {
                registTo?.unregisterReceiver(this@broadCastRecever)
                isRegisted = false
            }
        }
    }
}