一、什么是廣播
BroadcastReceiver是android 系統的四大組件之一，本質上就是一個全局的監聽器，用於監聽系統全局的廣播消息，可以方便的實現系統中不同組件之間的通信。
程序可以通過調用context的sendBroadcast()方法來啟動指定的BroadcastReceiver.
二、廣播的生命周期
BroadcastReceiver生命周期只有十秒左右，如果在onReceive()內做超過十秒的事情，就會報錯。所以廣播中不要執行耗時操作，可以考慮啟動一個Service來完成操作。
三、注冊BroadcastReceiver
廣播分為兩種：靜態注冊和動態注冊
1.靜態注冊
AndroidManifest.xml文件中配置
特點：常駐形廣播，程序推出后，廣播依然存在。
在AndroidManifest中進行注冊后，不管該應用程序是否處於活動狀態，都會進行監聽，比如某個程序是監聽 內存 的使用情況的，當在手機上安裝好后，
不管該應用程序是處於什么狀態，都會執行改監聽方法中的內容。
goal：創建廣播，新建一個類，繼承自BroadcastReceiver,並重寫onReceive()方法，在manifest文件中注冊該廣播，再發送廣播
2.動態注冊
代碼中動態指定廣播地址並注冊
在代碼中進行注冊后，當應用程序關閉后，就不再進行監聽。如果是在Activity中進行的注冊和解注冊，則生命周期是跟隨該Activity的。
特點：非常駐型，廣播會跟隨程序的生命周期的結束而結束
goal:新建內部類，繼承BroadcastReceiver,並重寫onReceive()方法，在onStart（）中注冊廣播，在onStop()中解除注冊廣播，在發送廣播
A、Send
1.1 activity_main.xml
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:gravity="center" android:orientation="vertical"> <Button android:id="@+id/btn1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="btn1" android:textSize="32sp" /> <Button android:id="@+id/btn2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="btn2" android:textSize="32sp" /> </LinearLayout>
1.2 MainActivity.java
package com.gatsby.intentfiltersend; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.content.IntentFilter; import android.os.Bundle; import android.view.Gravity; import android.view.View; import android.widget.Button; import android.widget.Toast; import androidx.appcompat.app.AppCompatActivity; public class MainActivity extends AppCompatActivity implements View.OnClickListener { Button btn1, btn2; CrushReceiver crushReceiver; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initView(); } public void initView() { btn1 = (Button) findViewById(R.id.btn1); btn2 = (Button) findViewById(R.id.btn2); btn1.setOnClickListener(this); btn2.setOnClickListener(this); } @Override public void onClick(View v) { switch (v.getId()) { case R.id.btn1: CrushRegister(); //發送動態廣播 Intent intent1 = new Intent(); intent1.setAction("com.android.crushGril"); intent1.putExtra("key", "CrsuhGril"); sendBroadcast(intent1); break; case R.id.btn2: //發送靜態廣播 Intent intent2 = new Intent(); intent2.setAction("com.android.gatsby"); sendBroadcast(intent2); break; } } //動態注冊廣播 public void CrushRegister() { //實例化IntentFilter對象 IntentFilter filter = new IntentFilter(); filter.addAction("com.android.crushGril"); crushReceiver = new CrushReceiver(); //注冊廣播接收 registerReceiver(crushReceiver, filter); } class CrushReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { //通過繼承 BroadcastReceiver建立動態廣播接收器 String action = intent.getAction(); if (action.equals("com.android.crushGril")) { //通過吐司驗證接收到廣播 Toast toast = Toast.makeText(context, "動態廣播：" + action + " value-->" + intent.getStringExtra("key"), Toast.LENGTH_SHORT); toast.setGravity(Gravity.TOP, 0, 0);//將吐司設置在屏幕頂端 toast.show(); } } } /*動態注冊需在Acticity生命周期onPause通過 *unregisterReceiver()方法移除廣播接收器， * 優化內存空間，避免內存溢出 */ @Override protected void onPause() { super.onPause(); unregisterReceiver(crushReceiver); } //在銷毀時要與廣播解綁 @Override protected void onDestroy() { super.onDestroy(); unregisterReceiver(crushReceiver); } }
1.3.XHService 動態注冊廣播
public void SerialPortWrite(String strcmd)
{
try
{
byte[] bytes = strcmd.getBytes();
mOutputBuffer.clear();
mOutputBuffer.put(bytes);
mSerialPort.write(mOutputBuffer, bytes.length);
Thread.sleep(200);
}
catch (Exception e)
{
e.printStackTrace();
}
}
XHService(Context context)
{
Log.d(TAG, "enter XHService");
mContext=context;
XHService_SerialInit();
IntentFilter filter = new IntentFilter();
filter.addAction(Intent.ACTION_TIME_CHANGED);
filter.addAction(Intent.ACTION_SCREEN_ON);
filter.addAction(Intent.ACTION_SCREEN_OFF);
filter.addAction(Intent.ACTION_BOOT_COMPLETED);
filter.addAction("com.xinhua.scheduled");
filter.addAction("com.xinhua.ethernet_static");
filter.addAction("com.xinhua.ethernet_enable");
filter.addAction("com.xinhua.ethernet_dhcp");
filter.addAction("xy.update.third.apk.start");
filter.addAction("com.xinhua.scheduledSysOrApi");
context.registerReceiver(mIntentReceiver, filter);
mEthManager = (EthernetManager) mContext.getSystemService(Context.ETHERNET_SERVICE);
mTelephonyManager = (TelephonyManager) mContext.getSystemService(Context.TELEPHONY_SERVICE);
if(SystemProperties.get("persist.rild.libpath","/system/lib/libreference-ril-ls-u8300.so")
.equals("/system/lib/libreference-ril-huawei-me909s.so")){
Thread thread = new Thread(NetChceck);
thread.start();
}
mHandler = new xhHandler(FgThread.get().getLooper());
}
mIntentReceiver 廣播接收
BroadcastReceiver mIntentReceiver = new BroadcastReceiver()
{
public void onReceive(Context context, Intent intent)
{
Log.d(TAG, "receiver intent :"+intent.getAction());
if (intent.getAction().equals(Intent.ACTION_TIME_CHANGED))
{
SetMcuTime();
}
B、Receiver 靜態注冊廣播、傳遞信息到活動頁面Activity
2.1 activity_main.xml
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:gravity="center" android:orientation="vertical"> <Button android:id="@+id/btn1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="btn1" android:textSize="32sp" /> <TextView android:id="@+id/tv1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="繪梨衣" android:textSize="64sp" /> </LinearLayout>
2.2 AndroidManifest.xml
<receiver android:name=".MyCrushBroadcastReceiver"> <intent-filter> <action android:name="com.android.crushGril" /> <action android:name="com.android.gatsby"/> </intent-filter> </receiver>
2.3 MainActivity.java
package com.gatsby.broadcastreceiver; import android.os.Bundle; import android.util.Log; import android.view.View; import android.widget.Button; import android.widget.TextView; import androidx.appcompat.app.AppCompatActivity; public class MainActivity extends AppCompatActivity implements View.OnClickListener { Button btn1; TextView tv1; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initView(); } public void initView() { tv1 = (TextView) findViewById(R.id.tv1); btn1 = (Button) findViewById(R.id.btn1); btn1.setOnClickListener(this); } @Override public void onClick(View v) { switch (v.getId()){ case R.id.btn1: MyCrushBroadcastReceiver myCrushBroadcastReceiver = new MyCrushBroadcastReceiver(); Log.d("gatsby","receive value!"+myCrushBroadcastReceiver.getGatsbySting()); tv1.setText(myCrushBroadcastReceiver.getGatsbySting()); break; } } }
2.3 MyCrushBroadcastReceiver.java
package com.gatsby.broadcastreceiver; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.widget.Toast; public class MyCrushBroadcastReceiver extends BroadcastReceiver { static String gatsbyString; @Override public void onReceive(Context context, Intent intent) { String action = intent.getAction(); if (action.equals("com.android.crushGril")) { Toast toast = Toast.makeText(context, "靜態廣播CrushGril:" + action + " value->" + intent.getStringExtra("key"), Toast.LENGTH_SHORT); toast.show(); } else if (action.equals("com.android.gatsby")) { gatsbyString = "Gatsby receive CrushGril"; Toast toast = Toast.makeText(context, "靜態廣Gatsby：->" + action + " value->", Toast.LENGTH_SHORT); toast.show(); } } //處理返回信息 public static String getGatsbySting() { return gatsbyString; } }