Dynamically change the margin of a Checkbox

Question

This attribute can be changed dynamically in java code?

android:layout_marginTop

I have a CheckBox dynamically generated, and I need him to have a margin.

_{Java code:}

CheckBox cb = new CheckBox(this);
//cb.setId();
//cb.setText();
cb.setChecked();
_relativeLayout.addView(cb);

Without the margin, it is displayed this way:

One on top of the other.

EDITION:

With the margin, it is not displayed.

ViewGroup.MarginLayoutParams ml = new ViewGroup.MarginLayoutParams(10, 10);
ml.setMargins(0, 5, 0, 0);
CheckBox cb = new CheckBox(this);
//cb.setId();
//cb.setText();
cb.setChecked(true);
cb.setLayoutParams(ml);
_relativeLayout.addView(cb);

ISSUE 2

RelativeLayout.LayoutParams ml = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
ml.setMargins(0, 5, 0, 0);
for (int i = 0; i < json.length(); i++) {   
    CheckBox cb = new CheckBox(this);
    //ml.addRule(RelativeLayout.BELOW, _relativeLayoutCbIngredientes);
    cb.setLayoutParams(ml);
    _relativeLayoutCbIngredientes.addView(cb);
}

Even though we set margem continues one on top of the other, the problem is not the margem, and I think so Bellow.

How to add the Bellow in the CheckBox and it is generated dynamically?

Answer 1

Edit: As the View which must be above CheckBox is generated dynamically, this solution using RelativeLayout.BELOW does not meet and generates problems even adding a id auto-generated. To each addView the RelativeLayout will need to reevaluate all rules, generating an "overhead" in the solution.

A simple solution would be to adopt a LinearLayout with orientation="vertical", because to each item inserted the LinearLayout puts it below the previous.

The only modification to the current code would be:

for (int i = 0; i < json.length(); i++) {

    // Precisa gerar um LayoutParams para cada View, não recomendo reutilizar.
    LinearLayout.LayoutParams ml = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);

    // Margem opcional
    ml.setMargins(0, 5, 0, 0);

    CheckBox cb = new CheckBox(this);
    cb.setLayoutParams(ml);

    _linearLayoutCbIngredientes.addView(cb);
}

---

To add dynamic margin in a View which is adding to the Layout, needs:

1. Create the LayoutParams specific to the subclass of ViewGroup that will add to View. The Builder of LayoutParams receives the layout_width and layout_height that the View will have.
2. Set values before calling addView(View view) or use the addView(View view, LayoutParams param).

An example:

RelativeLayout.LayoutParams ml = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);

// A classe RelativeLayout.LayoutParams extende MarginLayoutParams,
// verificado na documentacao: http://developer.android.com/reference/android/widget/RelativeLayout.LayoutParams.html

ml.setMargins(0, 5, 0, 0);

CheckBox cb = new CheckBox(this);

cb.setChecked(true);

// Ou
cb.setLayoutParams(ml);
_relativeLayout.addView(cb);

// Ou
_relativeLayout.addView(cb, ml);

As a suggestion, why not use a rule to position a View below another?

Using the rule would be:

RelativeLayout.LayoutParams ml = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);

// A classe RelativeLayout.LayoutParams extende MarginLayoutParams,
// verificado na documentacao: http://developer.android.com/reference/android/widget/RelativeLayout.LayoutParams.html

// Adiciona uma regra para o CheckBox ficar abaixo da View existente cujo id seja viewAcima.
// Parto do pressuposto que essa View ja esta no layout como mostrado na imagem.

ml.addRule(RelativeLayout.BELOW, R.id.viewAcima);

CheckBox cb = new CheckBox(this);

cb.setChecked(true);

// Ou
cb.setLayoutParams(ml);
_relativeLayout.addView(cb);

// Ou
_relativeLayout.addView(cb, ml);

In the latter case, the RelativeLayout will add one more restriction in your CheckBox should fall below the viewAcima.

I believe this form is more correct, because using a fixed margin can generate problems depending on the density and screen size and etc of the device. Therefore, it may be that in some devices the fixed margin given is not sufficient to place the CheckBox below the other View.