Android进阶之路 - 广播实现强制下线功能
阅读本文需 5分，理解本文需8分，copy本文需3分
修订于2019/11/1
采用的是Android中的广播机制，如果大家不理解广播的使用的话，可以通过以下地址进行学习（可以比较全面的理解和使用）
Android进阶之路 - 四大组件之BroadcaseReceiver
本篇学于郭霖大神的第一行代码（第二版），自我加以理解敲出自己的篇章 （很实用）
实现效果
前置了解
正确账号：123
正确密码：123
AndroidMainfest（进入初始Activity设置）
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.dow.accountintercept">
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/Theme.AppCompat.Light.NoActionBar">
<activity android:name=".LoginActivity"
android:launchMode="singleTask">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".MainActivity"
android:launchMode="singleTask"/>
</application>
</manifest>
准备工作 - 关键部分
- AccountReceiver - 下线广播接收器
package com.example.dow.accountintercept;
import android.app.AlertDialog;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
public class AccoutReceiver extends BroadcastReceiver {
@Override
public void onReceive(final Context context, Intent intent) {
AlertDialog.Builder dialog = new AlertDialog.Builder(context);
dialog.setTitle("警告");
dialog.setMessage("强制下线，请重新登陆");
dialog.setCancelable(false);
dialog.setPositiveButton("OK", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
ActivityCollector.finishAll();
context.startActivity(new Intent(context,LoginActivity.class));
}
});
dialog.show();
}
}
- ActivityCollector（采用的郭神的工具类）- Activity管理工具类
主要作用在当用户跳转登录界面时不会因为操作返回键而返回到app内部界面
package com.example.dow.accountintercept;
import android.app.Activity;
import java.util.ArrayList;
import java.util.List;
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();
}
}
}
}
- BaseActivity - 将ActivityCollector使用到Base中，从而实现Activity的收集与操作
package com.example.dow.accountintercept;
import android.content.IntentFilter;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
public class BaseActivity extends AppCompatActivity {
private AccountReceiver receiver;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ActivityCollector.addActivity(this);
}
@Override
protected void onResume() {
super.onResume();
IntentFilter intentFilter = new IntentFilter("ForcedDownline");
receiver = new AccountReceiver();
registerReceiver(receiver,intentFilter);
}
@Override
protected void onPause() {
super.onPause();
if(receiver != null){
unregisterReceiver(receiver);
receiver = null;
}
}
@Override
protected void onDestroy() {
super.onDestroy();
ActivityCollector.removeActivity(this);
}
}
实战场景
- MainActivity - 需执行下线操作的场景类
package com.example.dow.accountintercept;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends BaseActivity {
private TextView mBtn;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
init();
}
private void init() {
mBtn = (TextView) findViewById(R.id.tv_btn);
//在事件处理的内部进行发送广播
mBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent("ForcedDownline");
sendBroadcast(intent);
}
});
}
}
Xml - activity_main
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.dow.accountintercept.MainActivity">
<TextView
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:gravity="center"
android:text="登陆成功，这里是主界面" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="5dp"
android:text="强制下线"
android:layout_gravity="center"
android:background="#f00"
android:textColor="#fff"
android:id="@+id/tv_btn"
android:layout_marginBottom="30dp"
/>
</LinearLayout>
- LoginActivity - 执行下线操作后的登录界面
package com.example.dow.accountintercept;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class LoginActivity extends BaseActivity {
private EditText mAccount;
private EditText mPassword;
private TextView mLogin;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
initView();
initData();
}
private void initView() {
mAccount = (EditText) findViewById(R.id.ed_account);
mPassword = (EditText) findViewById(R.id.ed_password);
mLogin = (TextView) findViewById(R.id.tv_login);
}
private void initData() {
mLogin.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String eAccount=mAccount.getText().toString();
String ePassword= mPassword.getText().toString();
if(eAccount.equals("123")&&ePassword.equals("123")){
startActivity(new Intent(LoginActivity.this,MainActivity.class));
finish();
}else{
Toast.makeText(LoginActivity.this,"用户密码错误，请您重新输入",Toast.LENGTH_LONG).show();
}
}
});
}
}
Xml - activity_login
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:orientation="vertical"
android:layout_height="match_parent">
<LinearLayout
android:layout_marginTop="150dp"
android:layout_marginLeft="10dp"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
>
<TextView
android:text="账户："
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<EditText
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="wrap_content"
android:id="@+id/ed_account"/>
</LinearLayout>
<LinearLayout
android:layout_marginLeft="10dp"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
>
<TextView
android:text="密码："
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<EditText
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="wrap_content"
android:id="@+id/ed_password"/>
</LinearLayout>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="10dp"
android:text="登陆"
android:id="@+id/tv_login"
android:textColor="#fff"
android:background="#3F51B5"
android:layout_gravity="center"
/>
</LinearLayout>