Fragment adding - removing

Question

I want to add and remove a Fragment through a Button.. Following is the code for the MainActivity.

When clicking the button for the second time, I get the error message :

java.lang.IllegalStateException: Fragment already added..

Where is my error?

public class MainActivity extends AppCompatActivity {

private Button myBlackButton, myRedButton, myYellowButton;
private TopFragment topFragment;
private YellowFragment yellowFragment;
private RedFragment redFragment;
private boolean status_zwart = true;
private boolean status_geel = true;
private boolean status_rood = true;

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

    myBlackButton = (Button)findViewById(R.id.zwart_button);
    topFragment = new TopFragment();

    myBlackButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (status_zwart = true){
                getSupportFragmentManager()
                    .beginTransaction()
                    .add(R.id.fragment_container, topFragment)
                    .commit();
                status_zwart = false;
            }
            if (status_zwart = false) {
                getSupportFragmentManager()
                        .beginTransaction()
                        .remove(topFragment)
                        .commit();
                status_zwart = true;}
            }
    });

https://stackoverflow.com/questions/24517494/how-to-add-remove-fragment-on-button-click — Quick learner, Jun 15 '18 at 12:39

score 2 · Accepted Answer · edited Jun 15 '18 at 13:19

2

Use double equals for boolean checks:

if (status_zwart == true){
    getSupportFragmentManager()
        .beginTransaction()
        .add(R.id.fragment_container, topFragment)
        .commit();
    status_zwart = false;
}
if (status_zwart == false) {
    getSupportFragmentManager()
        .beginTransaction()
        .remove(topFragment)
        .commit();
    status_zwart = true;}
}

edited Jun 15 '18 at 13:19

AskNilesh

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answered Jun 15 '18 at 12:34

Levi Moreira

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1

even better `if (status_zwart){// logic}else{// logic}` – AskNilesh Jun 15 '18 at 13:20

score 2 · Answer 2 · edited Jun 15 '18 at 13:18

2

Edit your code as below

if (status_zwart) {
    getSupportFragmentManager().beginTransaction()
        .add(R.id.fragment_container, topFragment)
        .commit();
    status_zwart = false;
} else {
    getSupportFragmentManager().beginTransaction().remove(topFragment).commit();
    status_zwart = true;
}

edited Jun 15 '18 at 13:18

AskNilesh

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16
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answered Jun 15 '18 at 12:40

GianhTran

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Fragment adding - removing

2 Answers2