各位看官們大家好,上一回中咱們說的是Android中發送與接收有序廣播的例子,這一回咱們繼續說該例子。閒話休提,言歸正轉。讓我們一起Talk Android吧!
看官們,我們在上一章回中介紹了發送與接收有序廣播的操作步驟,本章回中將給出具體的代碼,請大家參考:
package com.example.talk8.blogapp06;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.widget.Button;
public class ActivityBroadCast extends AppCompatActivity {
private static final String TAG = "ActivityBroadCast";
//定義廣播接收器子類的對象
private OrderBroaccastReceiverA mOrderBroaccastReceiverA;
private OrderBroaccastReceiverB mOrderBroaccastReceiverB;
public Button mButtonSendOrderBroadcast;
// 定義廣播名稱;使用string類型的變量作爲廣播名稱;
private static final String NAME_ORDER_BROADCAST= "OrderBroadcast";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_broad_cast);
mButtonSendOrderBroadcast = (Button) findViewById(R.id.id_bt_send_order_bc);
//註冊兩個有序廣播接收器,它們的Action相同,但是優先級不同
//把優先級當作數據放到intentFilter中
IntentFilter intentFilter = null;
intentFilter = new IntentFilter();
intentFilter.addAction(NAME_ORDER_BROADCAST);
intentFilter.setPriority(10);
mOrderBroaccastReceiverA = new OrderBroaccastReceiverA();
registerReceiver(mOrderBroaccastReceiverA,intentFilter);
intentFilter.setPriority(20);
mOrderBroaccastReceiverB = new OrderBroaccastReceiverB();
registerReceiver(mOrderBroaccastReceiverB,intentFilter);
//設置Button的監聽器來發送有序廣播
mButtonSendOrderBroadcast.setOnClickListener(v -> sendOrderBroadcast());
}
@Override
protected void onDestroy() {
super.onDestroy();
Log.i(TAG, "onDestroy: unregisterReceiver");
// 銷燬廣播接收器
unregisterReceiver(mOrderBroaccastReceiverA);
unregisterReceiver(mOrderBroaccastReceiverB);
}
//發送有序廣播
public void sendOrderBroadcast() {
Log.i(TAG, "sendOrderBroadcast: ");
Intent intent = new Intent(NAME_ORDER_BROADCAST);
sendOrderedBroadcast(intent,null);
}
}
// 自定義兩個有序廣播接收器的子類並且重寫onReceive方法
class OrderBroaccastReceiverA extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
Log.i(TAG, "onReceive: data of OrderBroaccastReceiverA: ");
}
}
class OrderBroaccastReceiverB extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
Log.i(TAG, "onReceive: data of OrderBroaccastReceiverB: ");
}
}
}
我們在代碼中沒有像發送接收普通廣播一樣標記數字序號,不過在關鍵的地方都添加了註釋。相信大家可以看明白。另外,在代碼中我們註冊了兩個廣播接收器,發送廣播後這兩個接收器都可以收到廣播,只是優先級高的廣播接收器先收到廣播;這點從運行顯示的log中可以看出來。這裏就不列出運行時的Log了。
最後要說的是,如果在高優先級的廣播接收器中使用abortBroadcast()方法,那麼廣播的傳送就會被中斷,其它廣播接收器就不會收到廣播了。其實這種中斷機制在普通廣播中也可以使用,只是無法確定什麼時候中斷廣播傳輸而有序廣播中就可以放心使用了,我們可以劃定一個固定的廣播接收器優先級,低於此優先級的廣播接收器就不會收到廣播了,這種機制在項目中還是很有用處的。
各位看官,關於Android中發送和接收有序廣播的例子咱們就介紹到這裏,欲知後面還有什麼例子,且聽下回分解!