利用广播机制，实现程序的强制退出。

前面有篇博文，写到了一键退出，这里利用到了那里的ActivityCollector的集合和BaseActivity

功能：打开程序后，先登录，登录成功后，进入主页面，主页面有个按钮，点击后弹出窗口，用户点击 “是”之后退出程序


1、ActivityCollector

packagecom.yuanlp.forceexit;/***Createdby原立鹏on2017/6/28.*/importandroid.app.Activity;importjava.util.ArrayList;importjava.util.List;/***activity集合*/publicclassActivityCollector{publicstaticList<Activity>activityList=newArrayList<>();publicstaticvoidaddActivity(Activityactivity){activityList.add(activity);}publicstaticvoidremove(Activityactivity){activityList.remove(activity);}publicstaticvoidfinishAll(){for(Activityactivity:activityList){if(!activity.isFinishing()){//判断activity是否销毁activity.finish();//销毁activity}}}}2、BaseActivity作为后面activity的父类，继承自AppComapActivitypackagecom.yuanlp.forceexit;importandroid.content.BroadcastReceiver;importandroid.content.Context;importandroid.content.DialogInterface;importandroid.content.Intent;importandroid.content.IntentFilter;importandroid.os.Bundle;importandroid.support.v7.app.AlertDialog;importandroid.support.v7.app.AppCompatActivity;/***Createdby原立鹏on2017/6/28.*/publicclassBaseActivityextendsAppCompatActivity{privateMyForceExitReceiverreceiver;//声明一个自己的广播接收者内部类@OverrideprotectedvoidonCreate(BundlesavedInstanceState){super.onCreate(savedInstanceState);ActivityCollector.addActivity(this);}/***在activity处于返回栈顶，即处于焦点时，注册一个广播接收者*/publicvoidonResume(){super.onResume();IntentFilterintentFilter=newIntentFilter();//实例化一个intent过滤器intentFilter.addAction("com.yuanlp.exit.FORCEXIT");//只关心自己想要的广播receiver=newMyForceExitReceiver();registerReceiver(receiver,intentFilter);//动态注册广播}publicvoidonPause(){//当当前activity被弹出框占用时，解除注册super.onPause();if(receiver!=null){unregisterReceiver(receiver);receiver=null;}}publicvoidonDestroy(){super.onDestroy();ActivityCollector.finishAll();}/***一个广播接收者,接收到广播后，弹出框提示用户重新登录，强制退出*/privateclassMyForceExitReceiverextendsBroadcastReceiver{@OverridepublicvoidonReceive(finalContextcontext,finalIntentintent){AlertDialog.Builderbuilder=newAlertDialog.Builder(context);builder.setTitle("warning");builder.setMessage("你被强制退出，请重新登录");builder.setCancelable(false);//禁止用户取消这个弹框builder.setPositiveButton("OK",newDialogInterface.OnClickListener(){@OverridepublicvoidonClick(DialogInterfacedialog,intwhich){ActivityCollector.finishAll();//销毁所有活动Intentintent=newIntent(context,LoginActivity.class);//跳转至登录界面context.startActivity(intent);}});builder.show();}}}

3、LoginActivity 登录成功后，跳转到MainActivity界面。这里要在AndroidManifext.xml设置为这个activity是launcher,即打开后的第一个界面

packagecom.yuanlp.forceexit;importandroid.content.Intent;importandroid.os.Bundle;importandroid.view.View;importandroid.widget.EditText;publicclassLoginActivityextendsBaseActivity{privateEditTextmName;privateEditTextmPassword;@OverrideprotectedvoidonCreate(BundlesavedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.activity_login);mName=(EditText)findViewById(R.id.et_name);mPassword=(EditText)findViewById(R.id.et_password);}publicvoidlogin(Viewview){Stringname=mName.getText().toString().trim();Stringpassword=mPassword.getText().toString().trim();if("admin".equals(name)&&"123456".equals(password)){Intentintent=newIntent(this,MainActivity.class);startActivity(intent);}}}

4、activity_login.xml 简单的一个LinearLayout,vertical排版，里面放了2个水平布局的LinearLayout,分别放一个用户名和密码的EditText。最下方一个button，实现登录方法

<?xmlversion="1.0"encoding="utf-8"?><LinearLayoutxmlns: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="com.yuanlp.forceexit.LoginActivity"><LinearLayoutandroid:layout_width="match_parent"android:layout_height="60dp"android:orientation="horizontal"><EditTextandroid:id="@+id/et_name"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_weight="1"android:ems="10"android:hint="账号"android:inputType="textPersonName"/></LinearLayout><LinearLayoutandroid:layout_width="match_parent"android:layout_height="60dp"android:orientation="horizontal"><EditTextandroid:id="@+id/et_password"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_weight="1"android:ems="10"android:hint="密码"android:inputType="textPersonName"/></LinearLayout><Buttonandroid:id="@+id/button"android:layout_width="match_parent"android:layout_height="wrap_content"android:onClick="login"android:text="Button"/></LinearLayout>

5、MainActivity

里面主要的是一个button的方法，实现发送广播。

packagecom.yuanlp.forceexit;importandroid.content.Intent;importandroid.os.Bundle;importandroid.view.View;publicclassMainActivityextendsBaseActivity{@OverrideprotectedvoidonCreate(BundlesavedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);}publicvoidexit(Viewview){Intentintent=newIntent("com.yuanlp.exit.FORCEXIT");sendBroadcast(intent);//发送广播}}

6、activity_main.xml

<?xmlversion="1.0"encoding="utf-8"?><android.support.constraint.ConstraintLayoutxmlns: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="com.yuanlp.forceexit.MainActivity"><Buttonandroid:id="@+id/button2"android:layout_width="wrap_content"android:layout_height="wrap_content"android:onClick="exit"android:text="强制退出"app:layout_constraintBottom_toBottomOf="parent"app:layout_constraintTop_toTopOf="parent"tools:layout_editor_absoluteX="126dp"/></android.support.constraint.ConstraintLayout>