Android广播实现强制下线功能

蔚落 2022-01-21 03:21 265阅读 0赞

强制下线这个功能应该比较常见，很多应用都具备这个功能。  
首先创建一个ActivityCollect类用于管理所有活动

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

然后创建一个BaseActivity类作为所有活动的父类

package com.r.mybroadcast;
    
    import android.content.BroadcastReceiver;
    import android.content.Context;
    import android.content.DialogInterface;
    import android.content.Intent;
    import android.content.IntentFilter;
    import android.os.Bundle;
    import android.support.annotation.Nullable;
    import android.support.v7.app.AlertDialog;
    import android.support.v7.app.AppCompatActivity;
    
    public class BaseActivity extends AppCompatActivity {
        private ForceOfflineReceiver receiver;
        @Override
        protected void onCreate(@Nullable Bundle savedInstanceState) {
            super.onCreate (savedInstanceState);
            ActivityCollect.addActivity (this);
        }
    
        @Override
        protected void onResume() {
            super.onResume ();
            IntentFilter intentFilter =  new IntentFilter ();
            intentFilter.addAction ("com.r.mybroadcast.FORCE_OFFLINE");
            receiver = new ForceOfflineReceiver();
            registerReceiver (receiver,intentFilter);
        }
    
        @Override
        protected void onPause() {
            super.onPause ();
            if (receiver != null){
                unregisterReceiver (receiver);
                receiver = null;
            }
        }
    
        @Override
        protected void onDestroy() {
            super.onDestroy ();
            ActivityCollect.removeActivity (this);
        }
        class ForceOfflineReceiver extends BroadcastReceiver{
    
            @Override
            public void onReceive(final Context context, final Intent intent) {
                AlertDialog.Builder builder = new AlertDialog.Builder (context);
                //设置标题
                builder.setTitle ("Warning");
                //设置内容
                builder.setMessage ("You are force to be offline,Please try to login again.");
                //设置按钮以及对应的响应事件
                builder.setPositiveButton ("OK", new DialogInterface.OnClickListener () {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        //销毁所有活动
                        ActivityCollect.finishAll ();
                        Intent intent1 = new Intent (context,LoginActivity.class);
                        context.startActivity (intent1);
                    }
                });
                builder.show ();
            }
        }
    }

我们先创建一个用于登录的活动LoginActivity  
之后编写一下布局文件activity\_login

<?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:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        tools:context=".LoginActivity">
    
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="60dp"
            android:orientation="horizontal">
    
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="center_vertical"
                android:text="Account:"
                android:textSize="18sp" />
    
            <EditText
                android:id="@+id/id_account"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_gravity="center_vertical"
                android:layout_weight="1" />
        </LinearLayout>
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="60dp"
            android:orientation="horizontal">
    
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="center_vertical"
                android:text="Password:"
                android:textSize="18sp" />
    
            <EditText
                android:id="@+id/id_password"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_gravity="center_vertical"
                android:layout_weight="1" />
        </LinearLayout>
        <Button
            android:id="@+id/btn_login"
            android:layout_gravity="center_horizontal"
            android:text="Login"
            android:textStyle="bold"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />
    </LinearLayout>

之后就是LoginActivity的登录事件  
这里的话账号是admin密码是123，一定要对了才可以登录

package com.r.mybroadcast;
    
    import android.content.Intent;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.Button;
    import android.widget.EditText;
    import android.widget.Toast;
    
    public class LoginActivity extends BaseActivity {
    
        private EditText accountEdit;
        private EditText passwordEdit;
        private Button btnLogin;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate (savedInstanceState);
            setContentView (R.layout.activity_login);
            //初始化控件
            initView();
            //响应事件
            btnLogin.setOnClickListener (new View.OnClickListener () {
                @Override
                public void onClick(View v) {
                    String account = accountEdit.getText ().toString ();
                    String password = passwordEdit.getText ().toString ();
                    if (account.equals ("admin") && password.equals ("123") ){
                        Intent intent = new Intent (LoginActivity.this,MainActivity.class);
                        startActivity (intent);
                        finish ();
                    }else {
                        Toast.makeText (LoginActivity.this,"account or password is invalid",Toast.LENGTH_SHORT).show ();
                    }
                }
            });
        }
    
        private void initView() {
            accountEdit = findViewById (R.id.id_account);
            passwordEdit = findViewById (R.id.id_password);
            btnLogin = findViewById (R.id.btn_login);
        }
    }

然后在activity\_main布局里放一个Button  
主要是用于发送广播

BaseActivity类  
主要用于接受广播，收到对应的广播之后显示对话框  
用户只能单击Ok按钮  
然后重新跳转到登录的界面  
这样就实现了强制下线的功能啦

别忘了在AndroidMainfest中把LoginActivity设置为启动页  
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