一手遮天 Android - ipc（跨进程通信）: 发送广播（有序广播）
一手遮天 Android - ipc（跨进程通信）: 发送广播（有序广播）
示例如下:
/ipc/BroadcastDemo3.java
/**
* 本例用于演示如何发送有序广播，对应的的广播接收器采用动态注册的方式（即在 java 中注册）
*
* 标准广播和有序广播
* 1、标准广播就是发出去后，所有注册的监听器均会收到广播信息。
* 通过 sendBroadcast() 发送
* 2、有序广播就是发出去后，所有注册的监听器按优先级级别顺序接收。某一级接收器收到广播后，可以修改广播内容再向下传递，或者取消广播的向下传递。
* 通过 sendOrderedBroadcast() 发送
* 动态注册时通过 IntentFilter 的 setPriority() 指定优先级
* 静态注册时通过 intent-filter 的 android:priority 指定优先级
* 优先级的取值范围是 -1000 到 1000（值越大越优先）
*/
package com.webabcd.androiddemo.ipc;
import androidx.appcompat.app.AppCompatActivity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import com.webabcd.androiddemo.R;
import java.lang.ref.WeakReference;
public class BroadcastDemo3 extends AppCompatActivity {
public static final String ACTION_NAME = "cn.webabcd.broadcast.BroadcastDemo3";
private boolean mRegistered = false;
private TextView mTextView1;
private Button mButton1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_ipc_broadcastdemo3);
mButton1 = findViewById(R.id.button1);
mTextView1 = findViewById(R.id.textView1);
sample();
}
private void sample() {
registerReceiver();
mButton1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// 指定广播的名称
Intent intent = new Intent(ACTION_NAME);
// 指定广播传递的参数
intent.putExtra("p1", "v1");
// 指定有序广播的初始数据（这部分每一级接收器都是可以修改后再向下传递的）
int initialCode = 100;
String initialData = "abc";
Bundle initialExtras = new Bundle();
initialExtras.putString("p2", "v2");
// 发送有序广播
sendOrderedBroadcast(intent, null, null, null, initialCode, initialData, initialExtras);
}
});
}
@Override
protected void onDestroy() {
unregisterReceiver();
super.onDestroy();
}
public void appendText(String text) {
mTextView1.append(text);
mTextView1.append("\n");
}
// 动态注册指定的广播接收器
public void registerReceiver() {
mMyBroadcastReceiver = new MyBroadcastReceiver(this);
IntentFilter filter = new IntentFilter();
filter.addAction(ACTION_NAME);
filter.setPriority(500); // 指定优先级
this.registerReceiver(mMyBroadcastReceiver, filter);
mMyBroadcastReceiver2 = new MyBroadcastReceiver2(this);
IntentFilter filter2 = new IntentFilter();
filter2.addAction(ACTION_NAME);
filter2.setPriority(100); // 指定优先级
this.registerReceiver(mMyBroadcastReceiver2, filter2);
mRegistered = true;
}
// 动态注销指定的广播接收器
public void unregisterReceiver() {
if (mRegistered) {
try {
this.unregisterReceiver(mMyBroadcastReceiver);
this.unregisterReceiver(mMyBroadcastReceiver2);
mRegistered = false;
} catch (Exception e) {
e.printStackTrace();
}
}
}
// 自定义的广播接收器的实现
private MyBroadcastReceiver mMyBroadcastReceiver;
private static class MyBroadcastReceiver extends BroadcastReceiver {
// 用于保存本例中向此接收器发送广播的 activity（仅用于本例演示用）
private WeakReference<BroadcastDemo3> mActivity;
public MyBroadcastReceiver(BroadcastDemo3 activity) {
mActivity = new WeakReference<>(activity);
}
@Override
public void onReceive(Context context, Intent intent) {
if (BroadcastDemo3.ACTION_NAME.equals(intent.getAction())) {
// 获取接收到的广播的名称
String actionName = intent.getAction();
// 获取广播传递的参数
String p1 = intent.getStringExtra("p1");
// 获取有序广播的数据
int code = getResultCode();
String data = getResultData();
Bundle extras = getResultExtras(true);
String p2 = extras.getString("p2");
// 打印日志
mActivity.get().appendText(String.format("action1:%s, p1:%s, extras p2:%s, data:%s, code:%d", actionName, p1, p2, data, code));
// 修改有序广播的数据（下一级接收器将收到修改后的数据）
extras.putString("p2", "v2_modified");
setResultExtras(extras);
setResultData("xyz");
setResultCode(999);
// 取消有序广播的向下传递
// abortBroadcast();
}
}
}
// 自定义的广播接收器的实现
private MyBroadcastReceiver2 mMyBroadcastReceiver2;
private static class MyBroadcastReceiver2 extends BroadcastReceiver {
// 用于保存本例中向此接收器发送广播的 activity（仅用于本例演示用）
private WeakReference<BroadcastDemo3> mActivity;
public MyBroadcastReceiver2(BroadcastDemo3 activity) {
mActivity = new WeakReference<>(activity);
}
@Override
public void onReceive(Context context, Intent intent) {
if (BroadcastDemo3.ACTION_NAME.equals(intent.getAction())) {
// 获取接收到的广播的名称
String actionName = intent.getAction();
// 获取广播传递的参数
String p1 = intent.getStringExtra("p1");
// 获取有序广播的数据
int code = getResultCode();
String data = getResultData();
Bundle extras = getResultExtras(true);
String p2 = extras.getString("p2");
// 打印日志
mActivity.get().appendText(String.format("action1:%s, p1:%s, extras p2:%s, data:%s, code:%d", actionName, p1, p2, data, code));
}
}
}
}
/layout/activity_ipc_broadcastdemo3.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:orientation="vertical">
<Button
android:id="@+id/button1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textAllCaps="false"
android:text="发送广播" />
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
