定义
广播，是一个全局的监听器，属于Android四大组件之一.
Android 广播分为两个角色：广播发送者、广播接收者
2.广播接收器注册
注册的方式分为两种：静态注册、动态注册
静态注册:在AndroidManifest.xml里通过
动态注册:在代码中调用Context.registerReceiver()方法
3.广播接收代码案例(监听网络状态,动态注册)
①自定义一个类继承BroadcastReceiver
public class MyReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
//获取网络管理器类
ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
//网络信息
NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
if (networkInfo != null && networkInfo.isAvailable()) {
Toast.makeText(context, "有网！", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(context, "没网！", Toast.LENGTH_SHORT).show();
}
}
}
②动态注册广播
public class MainActivity extends AppCompatActivity {
private MyReceiver receiver;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//注册广播
receiver = new MyReceiver();
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction("android.net.conn.CONNECTIVITY_CHANGE");//接收网络变化
registerReceiver(receiver,intentFilter);
}
@Override
protected void onDestroy() {
super.onDestroy();
unregisterReceiver(receiver);//注销广播
}
}
③AndroidManifest.xml
4.广播接收(开启状态,静态注册)
①静态注册
public class MyReceiver2 extends BroadcastReceiver {
//广播接收器：接收系统开机广播
@Override
public void onReceive(Context context, Intent intent) {
Toast.makeText(context, "开机完成！", Toast.LENGTH_SHORT).show();
}
}
②AndroidManifest.xml,创建广播时选择New——Other——Broadcast Receiver会自动生成下面的标签
android:name=".reciver.MyReceiver2" android:enabled="true" android:exported="true"> 5.广播发送 广播的类型主要分为5类： 普通广播（Normal Broadcast） 系统广播（System Broadcast） 有序广播（Ordered Broadcast） 粘性广播（Sticky Broadcast） App应用内广播（Local Broadcast 下面只介绍了普通广播（标准广播）和有序广播 1.创建3个MyReceiver public class MyReceiver01 extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { Toast.makeText(context, "MyReceiver01", Toast.LENGTH_SHORT).show(); } } public class MyReceiver02 extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { Toast.makeText(context, "MyReceiver02", Toast.LENGTH_SHORT).show(); abortBroadcast();//拦截广播 } } public class MyReceiver03 extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { Toast.makeText(context, "MyReceiver03", Toast.LENGTH_SHORT).show(); } } 2.布局文件activity_main.xml android:text="标准" android:layout_width="match_parent" android:layout_height="wrap_content" android:id="@+id/btn_send"/> android:text="无序" android:layout_width="match_parent" android:layout_height="wrap_content"/> 3.MainActivity.java中 public class MainActivity extends AppCompatActivity implements View.OnClickListener { private Button btn_send; private Button btn_sendOrder; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main2); initView(); } private void initView() { btn_send = (Button) findViewById(R.id.btn_send); btn_sendOrder = (Button) findViewById(R.id.btn_sendOrder); btn_send.setOnClickListener(this); btn_sendOrder.setOnClickListener(this); } @Override public void onClick(View v) { switch (v.getId()) { case R.id.btn_send: Intent intent = new Intent("com.ABC"); sendBroadcast(intent);//发送标准广播 break; case R.id.btn_sendOrder: Intent intent2 = new Intent("com.ABC"); sendOrderedBroadcast(intent2, null);//发送有序广播 break; } } } 3.清单文件，AndroidManifest.xml android:name=".reciver2.MyReceiver01" android:enabled="true" android:exported="true"> android:name=".reciver2.MyReceiver02" android:enabled="true" android:exported="true"> android:name=".reciver2.MyReceiver03" android:enabled="true" android:exported="true">