Android之BroadcastReceiver(广播接受者)详解

约定不等于承诺〃 2022-09-28 11:37 214阅读 0赞

## 广播接受者又称全局大喇叭 ##

分为：标准广播、有序广播。
    
    标准广播：属于异步执行广播 ，广播发送出去以后广播接受器可以同时接收到，没有先后顺序 工作效率 无法拦截。
    
    有序广播：属于同步执行广播 广播发出去只有一个广播接受器能接受这一条广播。
    接受完毕以后广播接受器可以选择拦截或者，继续传给下一个接受器，优先级高优先收到广播 效率比较低。
    
    广播的两种注册方式
    静态：在清单文件中注册
    动态：在带代码中注册，必须onDestroy时取消注册

###  ###

### 1 .网络状态监听广播 ###

MainActivity.class

public class MainActivity extends BaseActivity { 
    
        private IntentFilter filter;
        private NetWorkChangeReceiver receiver;
    
        @Override
        protected int bindLayout() {
       //加载布局文件
            return R.layout.activity_main;
        }
    
        @Override
        protected void initView() {
       //初始化控件
            filter = new IntentFilter();//创建意图过滤器
            //添加网络变化的广播 filter.addAction("android.net.conn.CONNECTIVITY_CHANGE");
            receiver = new NetWorkChangeReceiver();//创建广播监听器
            registerReceiver(receiver, filter);//注册广播
        }
    
        protected void onDestroy() {
            super.onDestroy();
            unregisterReceiver(receiver);//解除注册
        }
    
        //监听网络变化的广播
        class NetWorkChangeReceiver extends BroadcastReceiver {
    
            @Override
            public void onReceive(Context context, Intent intent) {
                //判断网络连接还是没有连接
                ConnectivityManager connectivityManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
                NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
                if (networkInfo != null && networkInfo.isAvailable()) {
                    Toast.makeText(MainActivity.this, "网络已连接", Toast.LENGTH_SHORT).show();
                } else {
                    Toast.makeText(MainActivity.this, "网络断开", Toast.LENGTH_SHORT).show();
                }
            }
    
        }
    }

AndroidManifest.xml

### 2.标准广播 ###

MainActivity.class

public class MainActivity extends BaseActivity { 
        /*标准广播 发送标准广播（开启另一个程序） 步骤： 1.首先创建一个新项目 2.在新项目中创建广播接受器，在onReceive方法中 public void onReceive(Context context, Intent intent) { intent = new Intent(context,MainActivity.class); intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);//开启一个新栈 context.startActivity(intent); 3.在新项目清单中注册广播添加发送的广播频道 <action android:name="com.example.androidbroadcastreceiver.receiver.MyBroadcastReceiver" /> **在现在的程序中点击发送广播就能启动另一个程序了。** */
        @Override
        protected int bindLayout() {
            return R.layout.activity_standard_broadcast_receiver;
        }
    
        public void standardBR(View view) {
            Intent intent = new Intent("com.example.androidbroadcastreceiver.receiver.MyBroadcastReceiver");
            //intent.putExtra("广播", 2);//这里可以设置传值
            sendBroadcast(intent);
        }
    }

### 3.有序广播 ###

MainActivity.class

/*有序广播 发送有序广播(优先级高的 优先接收到广播) 3.设置优先级intent-filter android:priority="100" 优先级高的优先收到广播 拦截（abortBroadcast()）以后广播终端 */
    public class MainActivity extends AppCompatActivity { 
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_order_broadcast_receiver);
        }
    
        public void orderBR(View view) {
       //打开有序广播
            Intent intent = new Intent("com.example.androidbroadcastreceiver.receiver.MyBroadcastReceiver");
            intent.putExtra("广播", 3);
            sendOrderedBroadcast(intent, null);//发送有序广播需要两个参数1.intent 2.权限参数设置为null
    
        }
    }

MyBroadcastReceiver.class

//广播接受器
    public class MyBroadcastReceiver extends BroadcastReceiver { 
    
        @Override
        public void onReceive(Context context, Intent intent) {
            if (intent.getIntExtra("广播", 0) == 3) {
                Toast.makeText(context, "发送有序广播(优先级高的 优先接收到广播)\n" +
                        "并且终止广播禁止程序启动", Toast.LENGTH_SHORT).show();
            }
            abortBroadcast();//广播拦截，禁止向下传递
        }
    }

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
    <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.androidbroadcastreceiver">
    
        
        <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
        
        <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
    
        <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:supportsRtl="true" android:theme="@style/AppTheme">
            <activity android:name=".MainActivity">
                <intent-filter>
                    <action android:name="android.intent.action.MAIN" />
    
                    <category android:name="android.intent.category.LAUNCHER" />
                </intent-filter>
            </activity>
    
    
            <receiver android:name=".receiver.MyBroadcastReceiver" android:enabled="true" android:exported="true">
                 
                <intent-filter android:priority="100">
                    <action android:name="com.example.androidbroadcastreceiver.receiver.MyBroadcastReceiver" />
                </intent-filter>
            </receiver>
        </application>
    
    </manifest>

### 4.自定义广播 ###

MainActivity.class

/* 自定义广播 */
    public class MainActivity extends BaseActivity { 
    
        @Override
        protected int bindLayout() {
            return R.layout.activity_custom_broadcast_receiver;
        }
    
        public void customBR(View view) {
       //打开自定义广播
            Intent intent = new Intent("com.example.androidbroadcastreceiver.receiver.CustomBroadcastReceiver");
            intent.putExtra("zdy", "自定义广播");
            sendBroadcast(intent);
        }
    }

CustomBroadcastReceiver.class

/*自定义广播接受器 步骤： 1.创建广播接受器是必须勾选enabled、exported，否者接受不到广播 android:enabled="true" android:exported="true" 2.创建Intent i= new Intent("发送的广播"); 可以传值i.putString("标记"，"值")； sendBroadcast(intent); 然后接受器就能就收到广播啦！ */
    public class CustomBroadcastReceiver extends BroadcastReceiver { 
    
        @Override
        public void onReceive(Context context, Intent intent) {
            Toast.makeText(context, intent.getStringExtra("zdy"), Toast.LENGTH_SHORT).show();
        }
    }

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
    <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.androidbroadcastreceiver">
        <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:supportsRtl="true" android:theme="@style/AppTheme">
            <activity android:name=".MainActivity">
                <intent-filter>
                    <action android:name="android.intent.action.MAIN" />
    
                    <category android:name="android.intent.category.LAUNCHER" />
                </intent-filter>
            </activity>
    
            
            <receiver android:name=".receiver.CustomBroadcastReceiver" android:enabled="true" android:exported="true">
                <intent-filter>
                    <action android:name="com.example.androidbroadcastreceiver.receiver.CustomBroadcastReceiver" />
                </intent-filter>
            </receiver>
        </application>
    
    </manifest>

### 5.本地广播 ###

LocalBroadcastReceiverActivity.class

/* 本地广播 步骤： 1.首先创建LocalBroadcastManager对象管理广播、IntentFilter、LocalReceiver（广播接受器） 2.通过manager来注册、和解绑广播 3.本地广播只能在自身应用程序中使用，安全性高 */
    public class LocalBroadcastReceiverActivity extends AppCompatActivity { 
    
        private LocalBroadcastManager manager;
        private IntentFilter filter;
        private LocalReceiver receiver;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_local_broadcast_receiver);
            manager = LocalBroadcastManager.getInstance(this);
            filter = new IntentFilter();
            filter.addAction("com.example.androidbroadcastreceiver.activity.LocalBroadcastReceiverActivity.LocalReceiver");
            receiver = new LocalReceiver();
            manager.registerReceiver(receiver, filter);
    
        }
    
        public void localBR(View view) {
       //打开本地广播 安全不能跳转到别的程序
            Intent intent = new Intent("com.example.androidbroadcastreceiver.activity.LocalBroadcastReceiverActivity.LocalReceiver");
            intent.putExtra("bd", "我是刚创建的本地广播\n" +
                    "不能走出这个应用程序");
            manager.sendBroadcast(intent);
        }
    
        @Override
        protected void onDestroy() {
            super.onDestroy();
            manager.unregisterReceiver(receiver);
        }
    
        class LocalReceiver extends BroadcastReceiver {
            @Override
            public void onReceive(Context context, Intent intent) {
                Toast.makeText(context, intent.getStringExtra("bd"), Toast.LENGTH_SHORT).show();
            }
        }
    }

End!