Android 强制实现下线功能

界面

1.登录界面  activity_login.xml

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

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="60dp"
        android:orientation="horizontal">

        <TextView

            android:layout_width="90dp"
            android:layout_gravity="center_vertical"
            android:layout_height="wrap_content"
            android:textSize="18sp"
            android:text="Account:"/>

        <EditText
            android:id="@+id/account"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:layout_gravity="center_vertical"/>
    </LinearLayout>


    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="60dp"
        android:orientation="horizontal">

        <TextView
            android:layout_width="90dp"
            android:layout_gravity="center_vertical"
            android:layout_height="wrap_content"
            android:textSize="18sp"
            android:text="Password:"/>

        <EditText
            android:id="@+id/password"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:layout_gravity="center_vertical"
            android:inputType="textPassword"/>
    </LinearLayout>

    <Button
        android:layout_width="match_parent"
        android:layout_height="60dp"
        android:id="@+id/login"
        android:text="Login"/>

</LinearLayout>

2.主界面 activity_main.xml

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

    <Button
        android:id="@+id/force_offline"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Send offline broadcast"/>



</LinearLayout>

JAVA
1.MainActivity.java

package com.example.ken.broadcastbestpractice;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class MainActivity extends BaseActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button forceOffline = (Button) findViewById(R.id.force_offline);
        forceOffline.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent("com.example.broadcastbestpractice.FORCE_OFFLINE");
                sendBroadcast(intent);
            }
        });
    }
}

2.BaseActivity.java

package com.example.ken.broadcastbestpractice;

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 ForceOfflineReceive receiver;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ActivityCollector.addActivity(this);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        ActivityCollector.removeActivity(this);
    }

    @Override
    protected void onResume() {
        super.onResume();
        IntentFilter intentFilter = new IntentFilter();
        intentFilter.addAction("com.example.broadcastbestpractice.FORCE_OFFLINE");
        receiver = new ForceOfflineReceive();
        registerReceiver(receiver,intentFilter);
    }

    @Override
    protected void onPause() {
        super.onPause();
        if (receiver !=null){
            unregisterReceiver(receiver);
            receiver = null;
        }
    }

    class ForceOfflineReceive extends BroadcastReceiver{

        @Override
        public void onReceive(final Context context, Intent intent) {
            AlertDialog.Builder builder = new AlertDialog.Builder(context);
            builder.setTitle("Warning");
            builder.setMessage("You are forced to be offline. Please try to login again.");
            builder.setCancelable(false);
            builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialogInterface, int i) {
                    ActivityCollector.finishAll();
                    Intent intent = new Intent(context, LoginActivity.class);
                    context.startActivity(intent);
                }
            });
            builder.show();
        }
    }
}

3.LoginActivity.java

package com.example.ken.broadcastbestpractice;


import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.Nullable;
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 login;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        accountEdit = (EditText) findViewById(R.id.account);
        passwordEdit = (EditText) findViewById(R.id.password);
        login = (Button) findViewById(R.id.login);
        login.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String account = accountEdit.getText().toString();
                String password = passwordEdit.getText().toString();
                if (account.equals("account") && password.equals("123456")){
                    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();
                }
            }
        });
    }
}

4.ActivityCollector.java

package com.example.ken.broadcastbestpractice;

import android.app.Activity;

import java.util.ArrayList;
import java.util.List;

public class ActivityCollector {

    public static List<Activity> activities = new ArrayList<>();

    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();
            }
        }
    }
}

实现的效果：