文件目录
创建ActivityCollector类用于管理所有活动
package com.example.broadcastbestpratice;
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();
}
}
activities.clear();
}
}
强制下线功能需要关闭所有活动回到登录界面
创建BaseActivity类作为所有活动的父类
package com.example.broadcastbestpratice;
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);
ActivityCollector.addActivity(this);
}
@Override
protected void onPostResume() {
super.onPostResume();
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction("com.example.broadcastbestpratice.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();
ActivityCollector.removeActivity(this);
}
class ForceOfflineReceiver 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 dialog, int which) {
ActivityCollector.finishAll();
Intent intent = new Intent(context, LoginActivity.class);
context.startActivity(intent);
}
});
builder.show();
}
}
}
在BaseActivity动态注册广播接收器onReceive()中弹出对话框，点击OK后销毁所有活动并启动LoginActivity重写了onPostResume()和onPause()方法，在其中分别注册和取消广播接收，因为只有活动在栈顶时我们才需要强制下线功能
编写登陆布局（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:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="60dp">
<TextView
android:layout_width="90dp"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
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:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="60dp">
<TextView
android:layout_width="90dp"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
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:id="@+id/login"
android:layout_width="match_parent"
android:layout_height="60dp"
android:text="Login"/>
</LinearLayout>
修改LoginActivity
package com.example.broadcastbestpratice;
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 login;
@Override
protected void onCreate(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 v) {
String account = accountEdit.getText().toString();
String password = passwordEdit.getText().toString();
if (account.equals("admin") && 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();
}
}
});
}
}
在登陆按钮点击事件中只有输入正确的账户密码才能登陆并跳转至MainActivity
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns: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.example.broadcastbestpratice.MainActivity">
<Button
android:id="@+id/force_offline"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Send force offline broadcast"/>
</android.support.constraint.ConstraintLayout>
只需要一个按钮来实现强制下线
MainActivity
package com.example.broadcastbestpratice;
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 v) {
Intent intent = new Intent("com.example.broadcastbestpratice.FORCE_OFFLINE");
sendBroadcast(intent);
}
});
}
}
在按钮点击事件里发送了一条广播，值为com.example.broadcastbestpratice.FORCE_OFFLINE，这条广播就是用于通知程序强制下线的
将LoginActivity改为主活动
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.broadcastbestpratice">
<!-- To auto-complete the email text field in the login form with the user's emails -->
<uses-permission android:name="android.permission.GET_ACCOUNTS" />
<uses-permission android:name="android.permission.READ_PROFILE" />
<uses-permission android:name="android.permission.READ_CONTACTS" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
</activity>
<activity android:name=".LoginActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
