Java android-内存管理

我正在构建一个自定义锁屏，并面临RAM使用问题

服务占用的RAM最初为3MB。锁屏显示完成后，增加到8MB，并随着锁屏的后续启动而不断增加

我能够用下面的示例代码重现这个问题

MyService.java：

public void onCreate() {
    IntentFilter filter = new IntentFilter();
    filter.addAction(Intent.ACTION_SCREEN_ON);
    mReceiver = new MyReceiver();
    registerReceiver(mReceiver, filter);
}

MyReceiver.java

public void onReceive(Context context, Intent intent) {
    if (intent.getAction().equals(Intent.ACTION_SCREEN_ON)) {
        Intent startIntent = new Intent(context, SecondActivity.class);
        startIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK
            | Intent.FLAG_ACTIVITY_CLEAR_TOP);
        context.startActivity(startIntent);
    }
}

MainActivity.java：

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    startService(new Intent(this, MyService.class));
}

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD);
    setContentView(R.layout.activity_two);
}

@Override
public void onBackPressed() {
    finish();
}

SecondActivity.java：

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    startService(new Intent(this, MyService.class));
}

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD);
    setContentView(R.layout.activity_two);
}

@Override
public void onBackPressed() {
    finish();
}

activity_main.xml和activity_two.xml各自只包含一个文本视图