





<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<EditText
android:id="@+id/account"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:layout_gravity="center_vertical"/>


























两个界面布局

布局一 登录界面
<?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>
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<CheckBox
android:id="@+id/remember_pass"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="18sp"
android:text="Remember password" />
</LinearLayout>
<Button
android:id="@+id/login"
android:layout_width="match_parent"
android:layout_height="60dp"
android:text="Login" />
</LinearLayout>

布局二
主界面
<?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 force offline broadcast" />
</LinearLayout>
登录界面主活动




package com.example.broadcastbestpractice;
import android.content.Intent;
import android.content.SharedPreferences;
import android.preference.PreferenceManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.Toast;
public class LoginActivity extends BaseActivity {
private SharedPreferences pref;
private SharedPreferences.Editor editor;
private EditText accountEdit;
private EditText passwordEdit;
private Button login;
private CheckBox rememberPass;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);// 打开登陆布局
// 读取信息
pref = PreferenceManager.getDefaultSharedPreferences(this);
// 按键 编辑框ID
accountEdit = (EditText) findViewById(R.id.account);
passwordEdit = (EditText) findViewById(R.id.password);
rememberPass = (CheckBox) findViewById(R.id.remember_pass);
login = (Button) findViewById(R.id.login);
// 设置 可选按钮 否
boolean isRemember = pref.getBoolean("remember_password", false);
if (isRemember) {
// 将账号和密码 读取到文本框中
String account = pref.getString("account", "");
String password = pref.getString("password", "");
accountEdit.setText(account);
passwordEdit.setText(password);
rememberPass.setChecked(true);
}
// 登陆 按键函数
login.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String account = accountEdit.getText().toString();
String password = passwordEdit.getText().toString();
// 如果账号是admin且密码是123456,就认为登录成功
if (account.equals("admin") && password.equals("123456")) {
editor = pref.edit();
if (rememberPass.isChecked()) { // 检查复选框是否被选中
editor.putBoolean("remember_password", true);
editor.putString("account", account);
editor.putString("password", password);
} else {
editor.clear();
}
editor.apply();// 执行储存
Intent intent = new Intent(LoginActivity.this, MainActivity.class); //打开下个主界面
startActivity(intent);//开始
finish();//销毁当前
} else {
Toast.makeText(LoginActivity.this, "account or password is invalid",
Toast.LENGTH_SHORT).show();
}
}
});
}
}
主界面活动
package com.example.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 v) {
Intent intent = new Intent("com.example.broadcastbestpractice.FORCE_OFFLINE");
sendBroadcast(intent);
}
});
}
}

需要注册两个界面的关系
1 登录界面是主界面,自动启动
2 主界面是登陆界面,直接传递打开

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.broadcastbestpractice">
<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>

登录界面和主界面都继承了,重写了生成和销毁记录
BaseActivity类,里面添加了功能,能够很快管理所有的活动。例如销毁和生成

BaseActivity
package com.example.broadcastbestpractice;
import android.app.AlertDialog;
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.v7.app.AppCompatActivity;
public class BaseActivity extends AppCompatActivity {
private ForceOfflineReceiver receiver;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ActivityCollector.addActivity(this);
}
@Override
protected void onResume() {
super.onResume();
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction("com.example.broadcastbestpractice.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(); // 销毁所有活动
Intent intent = new Intent(context, LoginActivity.class);
context.startActivity(intent); // 重新启动LoginActivity
}
});
builder.show();
}
}
}
ActivityCollector
package com.example.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();
}
}
}
}
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