setVisibility（int）在回调中第二次不起作用

Question

I know similar questions have been asked before, however I could not find a thread that solved my problem. I have two overlapping elements (Layout and Button), on which I change the visibility through a callback method. The weird thing is, it works the first time, however if I try it the second time it doesn't work. When I click the button in the layout, the layout is set to View.GONE and the other button btn is set to View.VISIBLE . When I click the btn Button another Activity is started and from that activity this Activity is started again. That's when the visibility cannot be toggled again, but when I restart the entire application it works the first time. I also used a Handler instead of runOnUiThread(..) and it still did not work. I also checked the state of the visibility, the stat is visibile, however it is still not shown.

This is my code:

public class FirstActivity extends AppCompatActivity{

private LinearLayout buttonLayout;
private Button btn;

@Override
protected void onCreate(Bundle savedInstanceState) {
    ..
    buttonLayout = (LinearLayout) findViewById(R.id.buttonLayout);
    btn = (Button) findViewById(R.id.btn);
}

@Override
public void myCallback(int n){

   this.runOnUiThread(() -> {
       buttonLayout.setVisibility(View.GONE);
       btn.setVisibility(View.VISIBLE);

   });       
}

   public void onClick1(View view){
       Intent intent = new Intent(this, Result.class);
       startActivity(intent);
       finish();
   }
}

This is my layout:

<LinearLayout
android:id="@+id/buttonLayout"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="300px"
android:weightSum="1">

<Button
    android:layout_height="wrap_content"
    android:layout_width="wrap_content"
    android:text="x"
    android:textColor="@android:color/white"
    android:id="@+id/testNoBtn"
    android:onClick="onClick1"
    android:background="#f44336"
    android:layout_weight="0.45"
    android:enabled="false"
    android:visibility="visible"
    />

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_weight="0.1"
    />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="✔"
    android:textColor="@android:color/white"
    android:id="@+id/yesBtn"
    android:onClick="onClick2"
    android:background="#4caf50"
    android:layout_weight="0.45"
    />

</LinearLayout>

<Button
    android:id="@+id/btn"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="see result"
    android:background="#03a9f4"
    android:textColor="@android:color/white"
    android:layout_alignParentBottom="true"
    android:layout_marginTop="300px"
    android:onClick="onContinueClicked"
    android:visibility="invisible"
     />

This is the next Activity:

public class Result extends AppCompatActivity{

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_result);
        ...

    }

    public void tryAgain(){

        startActivity(new Intent("android.intent.action.FirstActivity"));
    }
}

Answer 1

before leaving FirstActivity return every visibility as it was meaning ...

add these two lines before leaving FirstActivity

btn.setVisibility(View.INVISIBLE);
buttonLayout.setVisibility(View.VISIBLE);

Answer 2

I finally solved it. The problem was lying in the thread calling the myCallback method. I was reusing the same thread, it would stay idle until I started it internally again. I fixed this by setting the thread to null in the callback method.