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Android 本地广播和强制下线功能的实现代码

【字号: 日期:2022-09-23 13:42:05浏览:19作者:猪猪

一、使用本地广播

1.本地广播一个举例

package com.example.broadcasttest2;import android.app.Activity;import android.content.BroadcastReceiver;import android.content.Context;import android.content.Intent;import android.content.IntentFilter;import android.net.ConnectivityManager;import android.net.NetworkInfo;import android.os.Bundle;import android.view.Menu;import android.view.MenuItem;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.Toast;public class MainActivity extends Activity { private IntentFilter intentFilter; private LocalReceiver localReceiver; private LocalBroadcastManager localBroadcastManager; private NetworkChangeReceiver networkChangeReceiver; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); intentFilter = new IntentFilter(); intentFilter.addAction('android.net.conn.CONNECTIVITY_CHANGE'); networkChangeReceiver = new NetworkChangeReceiver(); registerReceiver(networkChangeReceiver,intentFilter); localBroadcastManager = LocalBroadcastManager.getInstance(this);//获取实例 Button button = (Button) findViewById(R.id.button); button.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { //下面这行代码是用来全局广播的// Intent intent = new Intent('com.example.broadcasttest.MY_BROADCAST'); //下面这行代码是用来本地广播的(也就是app内部传递广播) Intent intent = new Intent('com.example.broadcasttest.LOCAL_BROADCAST'); localBroadcastManager.sendBroadcast(intent);//发送本地广播 // sendBroadcast(intent); //我们关闭上面一行代码,然后写另一种方法sendOrderedBroadcast,发送有序广播 sendOrderedBroadcast(intent,null); } }); intentFilter = new IntentFilter(); intentFilter.addAction('com.example.broadcasttest.LOCAL_BROACAST'); localReceiver = new LocalReceiver(); localBroadcastManager.registerReceiver(localReceiver,intentFilter);//注册本地广播监听器 } @Override protected void onDestroy() { super.onDestroy();// unregisterReceiver(networkChangeReceiver); localBroadcastManager.unregisterRecerver(localReceiver); } class NetworkChangeReceiver extends BroadcastReceiver{ @Override public void onReceive(Context context,Intent intent) { ConnectivityManager connectionMananger = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE); NetworkInfo networkInfo = connectionMananger.getActiveNetworkInfo(); if(networkInfo != null && networkInfo.isAvailable()) { Toast.makeText(context, 'network is available', Toast.LENGTH_SHORT).show(); } else { Toast.makeText(context, 'network is unavailable', Toast.LENGTH_SHORT).show(); } } } class LocalReceiver extends BroadcastReceiver { @Override public void onReceive(Context context,Intent intent) { Toast.makeText(context,'received local broadcast',Toast.LENGTH_SHORT).show(); } }}

通过LocalBroadcastManager的getInstance()方法来获取一个实例,注册广播是用的registerReceiver()方法,传入的参数一个是localReceiver的内部实例,一个是IntentFilter实例。最后在onCreate方法中调用发送广播的方法。最后我们在按钮的点击事件里面发送一条com.example.broadcasttest.LOCAL_BROADCAST广播,然后在LocalReceiver里面去接收这条广播。

注意点:本地广播是无法通过静态注册的方式来接收的,其实这也完全可以理解,因为静态注册主要就是为了让程序在未启动的时候也能收到广播,而发送本地广播的时候,我们的程序就已经启动了,因为也完全不需要使用静态注册的功能。

2.使用本地广播的优势

(1)程序内部传递,防止机密数据泄露;(2)其他程序无法将广播发送到我们的程序内部,防止安全漏洞的隐患;(3)发送本地广播更加高效。

二、实现强制下线功能

1.实现强制下线的逻辑

无论在我们在程序的哪个活动界面,一旦收到强制下线的广播,就跳出来一个界面,必须点击“确认“,然后直接跳转到登录界面。

2.首先创建一个类用于管理所有的活动

package com.example.broadcastbestpractice;import java.util.ArrayList;import java.util.List;import android.app.Activity;public class ActivityCollector { public static List<Activity> activities = new ArrayList<Activity>(); public static void addActivity(Activity activity) { activities.add(activity); } public static void removeActivity(Activity activity) { activities.remove(activity); } public static void finishAll() { for(Activity activity :activities) { if(!activity.isFinishing()) { activity.finish(); } } }}

3.创建一个基类BaseActivity作为所有活动的父类

package com.example.broadcastbestpractice;import android.app.Activity;import android.os.Bundle;public class BastActivity extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); ActivityCollector.addActivity(this); } @Override public void onDestroy() { super.onDestroy(); ActivityCollector.removeActivity(this); }}

4.接着需要建立一个登录页面的布局

<?xml version='1.0' encoding='utf-8'?><!-- android:shrinkColumns设置允许被收缩的列序号 android:strectColumns设置允许被拉伸的列序号 --><TableLLayout xmlns:android='http://schemas.android.com/apk/res/android' android:layout_width='match_parent' android:layout_height='match_parent' android:strectColumns = '1' > <TableRow> <TextView android:layout_height = 'wrap_content' android:text='Account:' /> <EditText android: android:layout_height='wrap_content' android:hint='Input your account' /> </TableRow> <TableRow> <TextView android:layout_height='wrap_content' android:text='Password:' /> <EditTest android: android:layout_height='wrap_content' android:inputType='textPassword' /> </TableRow> <TableRow> <Button android: android:layout_height='wrap_content' android:layout_span='2' android:text='Login' /> </TableRow></TableLayout>

后面的我们下次连载接着写。

三、源码:

BroadcastTest2BroadcastBestPracticehttps://github.com/ruigege66/Android/tree/master/BroadcastTest2https://github.com/ruigege66/Android/tree/master/BroadcastBestPractice

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