动态注册Receiver接收系统广播

需求描述

ToggleButton的状态为不检测时,TextView显示Hello Broad字符串

当点击ToggleButton后,TextView显示当前电量信息(要求能够实时刷新)

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<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity"
android:orientation="vertical"
android:gravity="center_horizontal">

<ToggleButton
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/tb_broad"
android:paddingVertical="20dp"
android:textSize="30sp"
android:textOn="检测"
android:textOff="不检测"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toTopOf="@id/tv_broad"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/tv_broad"
android:text="HelloWorld!"
android:textSize="30sp"/>

</LinearLayout>
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package com.example.broadcasttest;

import androidx.appcompat.app.AppCompatActivity;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.BatteryManager;
import android.os.Bundle;
import android.util.Log;
import android.widget.CompoundButton;
import android.widget.TextView;
import android.widget.ToggleButton;

public class MainActivity extends AppCompatActivity {
private final String TAG = MainActivity.class.getSimpleName();
private ToggleButton mTbBroad;
private TextView mTvBroad;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mTbBroad = findViewById(R.id.tb_broad);
mTvBroad = findViewById(R.id.tv_broad);
MyReceiver myReceiver = new MyReceiver();
mTbBroad.setOnCheckedChangeListener((CompoundButton cb, boolean b)->{
Log.d(TAG, Boolean.valueOf(b).toString());
if(b) {
IntentFilter filter = new IntentFilter();
filter.addAction(Intent.ACTION_BATTERY_CHANGED);
registerReceiver(myReceiver, filter);
}else{
mTvBroad.setText("Hello Broad");
unregisterReceiver(myReceiver);
}
});
}

public class MyReceiver extends BroadcastReceiver {
private final String TAG = MyReceiver.class.getSimpleName();
@Override
public void onReceive(Context context, Intent intent) {
Log.d(TAG, intent.getAction());
if(intent.getAction().equals(Intent.ACTION_BATTERY_CHANGED)) {
Bundle extras = intent.getExtras();
// 当前电量水平
int level = extras.getInt(BatteryManager.EXTRA_LEVEL);
// 电量最大值
int scale = extras.getInt(BatteryManager.EXTRA_SCALE);
// 电量百分数
int percent = (int)(((double)level/(double)scale)*100);
mTvBroad.setText("电量为:"+percent+"%");
}
}
}
}

静态注册Receiver

创建了一个静态的StaticReceiver后,代码如下

使用ide的新建静态Receiver之后,AndroidManifest.xml中就会自动插入以下代码

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<receiver
android:name=".StaticReceiver"
android:enabled="true"
android:exported="true"></receiver>
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package com.example.broadcasttest;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;
import android.widget.Toast;

public class StaticReceiver extends BroadcastReceiver {

@Override
public void onReceive(Context context, Intent intent) {
Log.d("StaticReceiver", "onReceive");
Toast.makeText(context, "From static receive", Toast.LENGTH_SHORT).show();
}
}

MainActivity.java中加入以下声明周期定义,

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@Override
protected void onResume() {
super.onResume();
mBtnStatic.setOnClickListener((View view)->{
Intent intent = new Intent();
intent.setClass(this, StaticReceiver.class);
sendBroadcast(intent);
});
}

普通广播定义

当点击ToggleButton时,若状态为普通广播,则通过广播修改TextView为Normal Broad,否则改为默认的Hello Broad

onResume()生命周期中添加

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NormalReceiver normalReceiver = new NormalReceiver();
mTbNormal.setOnCheckedChangeListener((CompoundButton cb, boolean b)->{
if(b) {
IntentFilter filter = new IntentFilter();
filter.addAction("intent.normal");
registerReceiver(normalReceiver, filter);

Intent intent = new Intent();
intent.setAction("intent.normal");
sendBroadcast(intent);
}else{
mTvBroad.setText("Hello Broad");
unregisterReceiver(normalReceiver);
}
});

定义NormalReceiver内部类

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public class NormalReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
if(intent.getAction().equals("intent.normal")) {
mTvBroad.setText("Normal Broad");
}
}
}

本地广播

效果同普通广播,只不过写代码的方式不同,仅能实现应用程序自身通信

onResume()生命周期中添加

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LocalReceiver localReceiver = new LocalReceiver();
LocalBroadcastManager localBroadcastManager = LocalBroadcastManager.getInstance(this);
mTbLocal.setOnCheckedChangeListener((CompoundButton cb, boolean b)->{
if(b) {
IntentFilter filter = new IntentFilter("intent.local");
localBroadcastManager.registerReceiver(localReceiver,filter);
Intent intent = new Intent("intent.local");
localBroadcastManager.sendBroadcast(intent);
}else{
mTvBroad.setText("Hello Broad");
localBroadcastManager.unregisterReceiver(localReceiver);
}
});

定义 LocalReceiver内部类

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public class LocalReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
if(intent.getAction().equals("intent.local")) {
mTvBroad.setText("Local Broad");
}
}
}

有序广播

onResume添加

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Order1Receiver order1Receiver = new Order1Receiver();
Order2Receiver order2Receiver = new Order2Receiver();
mTbOrder.setOnCheckedChangeListener((CompoundButton cb, boolean b)->{
if(b) {
IntentFilter filter1 = new IntentFilter("intent.order");
filter1.setPriority(99);
registerReceiver(order1Receiver, filter1);

IntentFilter filter2 = new IntentFilter("intent.order");
filter2.setPriority(101);
registerReceiver(order2Receiver, filter2);

Intent intent = new Intent("intent.order");
sendOrderedBroadcast(intent,null);
}else{
mTvBroad.setText("Hello Broad");
unregisterReceiver(order1Receiver);
unregisterReceiver(order2Receiver);
}
});

定义Receiver内部类

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public class Order1Receiver extends BroadcastReceiver {

@Override
public void onReceive(Context context, Intent intent) {
if(intent.getAction().equals("intent.order")) {
mTvBroad.setText("Order1 Broad");
}
}
}
public class Order2Receiver extends BroadcastReceiver {

@Override
public void onReceive(Context context, Intent intent) {
if(intent.getAction().equals("intent.order")) {
mTvBroad.setText("Order2 Broad");
}
}
}

结果如下,

先执行优先级大的,所以先执行order2,最后执行order1

终止传播

修改Order2Receiver定义,加入终止传播的代码

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public class Order2Receiver extends BroadcastReceiver {

@Override
public void onReceive(Context context, Intent intent) {
if(intent.getAction().equals("intent.order")) {
mTvBroad.setText("Order2 Broad");
setResultData("From Order2");
// 终止传播
abortBroadcast();
}
}
}

完整代码如下

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package com.example.broadcasttest;

import androidx.appcompat.app.AppCompatActivity;
import androidx.localbroadcastmanager.content.LocalBroadcastManager;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.BatteryManager;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.CompoundButton;
import android.widget.TextView;
import android.widget.ToggleButton;

public class MainActivity extends AppCompatActivity {
private final String TAG = MainActivity.class.getSimpleName();
private ToggleButton mTbBroad, mTbNormal,mTbLocal, mTbOrder;
private TextView mTvBroad;
private Button mBtnStatic;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mTbBroad = findViewById(R.id.tb_broad);
mTvBroad = findViewById(R.id.tv_broad);
mBtnStatic = findViewById(R.id.btn_static);
mTbNormal = findViewById(R.id.tb_normal_broad);
mTbLocal = findViewById(R.id.tb_local_broad);
mTbOrder = findViewById(R.id.tb_order_broad);

MyReceiver myReceiver = new MyReceiver();
mTbBroad.setOnCheckedChangeListener((CompoundButton cb, boolean b)->{
Log.d(TAG, Boolean.valueOf(b).toString());
if(b) {
IntentFilter filter = new IntentFilter();
filter.addAction(Intent.ACTION_BATTERY_CHANGED);
registerReceiver(myReceiver, filter);
}else{
mTvBroad.setText("Hello Broad");
unregisterReceiver(myReceiver);
}
});
}

@Override
protected void onResume() {
super.onResume();
mBtnStatic.setOnClickListener((View view)->{
Intent intent = new Intent();
intent.setClass(this, StaticReceiver.class);
sendBroadcast(intent);
});

NormalReceiver normalReceiver = new NormalReceiver();
mTbNormal.setOnCheckedChangeListener((CompoundButton cb, boolean b)->{
if(b) {
IntentFilter filter = new IntentFilter();
filter.addAction("intent.normal");
registerReceiver(normalReceiver, filter);

Intent intent = new Intent();
intent.setAction("intent.normal");
sendBroadcast(intent);
}else{
mTvBroad.setText("Hello Broad");
unregisterReceiver(normalReceiver);
}
});

LocalReceiver localReceiver = new LocalReceiver();
LocalBroadcastManager localBroadcastManager = LocalBroadcastManager.getInstance(this);
mTbLocal.setOnCheckedChangeListener((CompoundButton cb, boolean b)->{
if(b) {
IntentFilter filter = new IntentFilter("intent.local");
localBroadcastManager.registerReceiver(localReceiver,filter);
Intent intent = new Intent("intent.local");
localBroadcastManager.sendBroadcast(intent);
}else{
mTvBroad.setText("Hello Broad");
localBroadcastManager.unregisterReceiver(localReceiver);
}
});

Order1Receiver order1Receiver = new Order1Receiver();
Order2Receiver order2Receiver = new Order2Receiver();
mTbOrder.setOnCheckedChangeListener((CompoundButton cb, boolean b)->{
if(b) {
IntentFilter filter1 = new IntentFilter("intent.order");
filter1.setPriority(99);
registerReceiver(order1Receiver, filter1);

IntentFilter filter2 = new IntentFilter("intent.order");
filter2.setPriority(101);
registerReceiver(order2Receiver, filter2);

Intent intent = new Intent("intent.order");
sendOrderedBroadcast(intent,null);
}else{
mTvBroad.setText("Hello Broad");
unregisterReceiver(order1Receiver);
unregisterReceiver(order2Receiver);
}
});
}

public class Order1Receiver extends BroadcastReceiver {

@Override
public void onReceive(Context context, Intent intent) {
if(intent.getAction().equals("intent.order")) {
mTvBroad.setText("Order1 Broad");
}
}
}
public class Order2Receiver extends BroadcastReceiver {

@Override
public void onReceive(Context context, Intent intent) {
if(intent.getAction().equals("intent.order")) {
mTvBroad.setText("Order2 Broad");
setResultData("From Order2");
// 终止传播
abortBroadcast();
}
}
}
public class LocalReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
if(intent.getAction().equals("intent.local")) {
mTvBroad.setText("Local Broad");
}
}
}

public class NormalReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
if(intent.getAction().equals("intent.normal")) {
mTvBroad.setText("Normal Broad");
}
}
}

public class MyReceiver extends BroadcastReceiver {
private final String TAG = MyReceiver.class.getSimpleName();
@Override
public void onReceive(Context context, Intent intent) {
Log.d(TAG, intent.getAction());
if(intent.getAction().equals(Intent.ACTION_BATTERY_CHANGED)) {
Bundle extras = intent.getExtras();
// 当前电量水平
int level = extras.getInt(BatteryManager.EXTRA_LEVEL);
// 电量最大值
int scale = extras.getInt(BatteryManager.EXTRA_SCALE);
// 电量百分数
int percent = (int)(((double)level/(double)scale)*100);
mTvBroad.setText("电量为:"+percent+"%");
}
}
}
}
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<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity"
android:orientation="vertical"
android:gravity="center_horizontal">

<ToggleButton
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/tb_broad"
android:paddingVertical="20dp"
android:textSize="30sp"
android:textOn="检测"
android:textOff="不检测"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/tv_broad"
android:text="HelloWorld!"
android:textSize="30sp"/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/btn_static"
android:textSize="30sp"
android:text="静态注册"/>
<ToggleButton
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/tb_normal_broad"
android:paddingVertical="20dp"
android:textSize="30sp"
android:textOn="普通广播"
android:textOff="不注册普通广播"/>
<ToggleButton
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/tb_local_broad"
android:paddingVertical="20dp"
android:textSize="30sp"
android:textOn="本地广播"
android:textOff="不注册本地广播"/>
<ToggleButton
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/tb_order_broad"
android:paddingVertical="20dp"
android:textSize="30sp"
android:textOn="有序广播"
android:textOff="不注册有序广播"/>

</LinearLayout>