Android使用广播(BroadCast)实现强制下线的方法

package com.example.broadcastpractice;
import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
/**
 * 所有活动管理器
 * @author yy
 *
 */
public class ActivityCollector {
  public static List activities = new ArrayList();
  /**
   * 添加活动
   * @param activity
   */
  public static void addActivity(Activity activity){
    if(!activities.contains(activity)){
     activities.add(activity);
 }
  }
  /**
   * 移除活动
   * @param activity
   */
  public static void removeActivity(Activity activity){
    activities.remove(activity);
  }
  /**
   * 结束所有活动
   */
  public static void finishAll(){
    for(Activity activity : activities){
      if(!activity.isFinishing()){
        activity.finish();
      }
    }
  }
}

package com.example.broadcastpractice;
import android.app.Activity;
import android.os.Bundle;
/**
 * 所有活动的基类
 * @author yy
 *
 */
public class BaseActivity extends Activity {
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    //每创建一个活动，就加入到活动管理器中
    ActivityCollector.addActivity(this);
  }
  @Override
  protected void onDestroy() {
    super.onDestroy();
    //每销毁一个活动，就从活动管理器中移除
    ActivityCollector.removeActivity(this);
  }
}

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package com.example.broadcastpractice;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
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 loginButton;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    //首先调用父类的方法
    super.onCreate(savedInstanceState);
    //加载登陆布局
    setContentView(R.layout.login);
    //获取输入内容
    accountEdit = (EditText) findViewById(R.id.account);
    passwordEdit = (EditText) findViewById(R.id.password);
    loginButton = (Button) findViewById(R.id.login);
    //注册按钮点击事件
    loginButton.setOnClickListener(new OnClickListener() {
      @Override
      public void onClick(View v) {
         String account = accountEdit.getText().toString();
         String password = passwordEdit.getText().toString();
        if(account.equals("yy") && password.equals("123456")){
          //登陆成功
          //启用MainActivity活动
          Intent intent = new Intent(LoginActivity.this,MainActivity.class);
          //启动
          startActivity(intent);
          //当前活动销毁
          finish();
        }else{
          //登陆失败
          //清空内容
          accountEdit.setText("");
          passwordEdit.setText("");
          Toast.makeText(LoginActivity.this, "登陆失败，请重新登陆！！", Toast.LENGTH_SHORT).show();
        }
      }
    });
  }
}

package com.example.broadcastpractice;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
/**
 * 继承BaseActivity
 * @author yy
 *
 */
public class MainActivity extends BaseActivity {
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    //获取按钮
    Button forceOffline = (Button) findViewById(R.id.force_offline);
    //注册事件
    forceOffline.setOnClickListener(new OnClickListener() {
      @Override
      public void onClick(View v) {
        //启用广播
        Intent intent = new Intent("com.example.broadcastpractice.FORCE_OFFLINE");
        //发送广播--标准广播
        sendBroadcast(intent);
      }
    });
  }
  @Override
  public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
  }
}

package com.example.broadcastpractice;
import android.app.AlertDialog;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.content.Intent;
import android.view.WindowManager;
/**
 * 强制下线广播接收器
 * @author yy
 *
 */
public class ForceOfflineBroadCastReceiver extends BroadcastReceiver {
  @Override
  public void onReceive(final Context context, Intent intent) {
    //对话框
    AlertDialog.Builder builder = new AlertDialog.Builder(context);
    builder.setTitle("警告");
    //正文
    builder.setMessage("你已被强制下线，请重新登陆。");
    //不可取消
    builder.setCancelable(false);
    //按钮
    builder.setPositiveButton("确定", new OnClickListener() {
      @Override
      public void onClick(DialogInterface dialog, int which) {
        //销毁所有活动
        ActivityCollector.finishAll();
        //启动登陆活动
        Intent intent = new Intent(context,LoginActivity.class);
        //在广播中启动活动，需要添加如下代码
        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        context.startActivity(intent);
      }
    });
    AlertDialog alterDialog = builder.create();
    //添加对话框类型：保证在广播中正常弹出
    alterDialog.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT);
    //对话框展示
    alterDialog.show();
  }
}

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