Android-浅谈广播机制，实现强制下线功能（下）

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() {   //按钮注册事件
            @Override
            public void onClick(View v) {
                String account=accountEdit.getText().toString();    //获取账号输入框的信息
                String password=passwordEdit.getText().toString();  //获取密码输入框的信息
                if(account.equals("admin")&&password.equals("password")){     //判断输入是否正确
                    Intent intent=new Intent(LoginActivity.this,MainActivity.class);
                    startActivity(intent);
                    finish();
                }
                else{
                    Toast.makeText(LoginActivity.this, "输入有误，请重新输入", Toast.LENGTH_SHORT).show();
                }
            }
        });
    }
}

<LinearLayout xmlns: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"
    tools:context=".MainActivity">
    <Button
        android:id="@+id/force_offline"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="强制下线按钮"/>
</LinearLayout>

public class MainActivity extends BaseActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button button=(Button) findViewById(R.id.force_offline);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent=new Intent("com.example.xiaxian");
                sendBroadcast(intent);      //发送广播
            }
        });
    }

public class BaseActivity extends AppCompatActivity {
    private ForceOfflineReceiver receiver;
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ActivityCollector.addActivity(this);
    }
    protected void onResume(){
        super.onResume();
        IntentFilter intentFilter=new IntentFilter();
        intentFilter.addAction("com.example.xiaxian");
        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);     //取消广播
    }
    class ForceOfflineReceiver extends BroadcastReceiver{
        @Override
        public void onReceive(final Context context, Intent intent) {
            AlertDialog.Builder builder=new AlertDialog.Builder(context);       //构建一个对话框
            builder.setTitle("warning");            //对话框标题
            builder.setMessage("You are forced to be offline. Please try to login agaun");      //内容
            builder.setCancelable(false);       //不可取消活动（即无法通过返回键取消活动）
            builder.setPositiveButton("OK",new DialogInterface.OnClickListener(){   //对话框注册确定按钮
                @Override
                    public void onClick(DialogInterface dialog, int which) {
                        ActivityCollector.finish(); //强制下线,即销毁所有活动
                        Intent intent=new Intent(context,LoginActivity.class);
                        context.startActivity(intent);      //重新启动LoginActivity
                    }
                });
            builder.show();
        }
    }
}

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.a15094.broadcastbestpractice">
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        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>