android以编程方式创建RelativeLayout

Question

I'm having some troubles creating a relativeLayout programmatically.For better understanding I attached a picture below. The things with plus and minus are buttons, which should also be dynamically created and added to the layout. The values of tv4 and tv5 should increase/decrease accordingly to button presses.

What I have done so far:

1) creating the layout:

RelativeLayout rl = new RelativeLayout(this);
    rl.setId(i);
    rl.setBackgroundResource(R.drawable.bg);
 RelativeLayout.LayoutParams Lparams = new RelativeLayout.LayoutParams(
                RelativeLayout.LayoutParams.MATCH_PARENT,
                RelativeLayout.LayoutParams.WRAP_CONTENT);
        Lparams.addRule(RelativeLayout.BELOW, R.id.RL_default);
        Lparams.setMargins(3, 5, 3, 0);
        rl.setLayoutParams(Lparams);

2) adding the tv1:

  Lparams = new RelativeLayout.LayoutParams(
            RelativeLayout.LayoutParams.MATCH_PARENT,
            RelativeLayout.LayoutParams.WRAP_CONTENT);
    Lparams.addRule(RelativeLayout.ALIGN_PARENT_LEFT, RelativeLayout.TRUE);
    Lparams.setMargins(10, 0, 0, 0);

    TextView txt = new TextView(this);
    txt.setTextColor(Color.parseColor("#FFFFFF"));
    txt.setId(x);
    txt.setTextSize(25);
    txt.setLayoutParams(Lparams);
    txt.setText(name);
            rl.addView(txt);

3) adding the tv2:

           Lparams = new RelativeLayout.LayoutParams(
            RelativeLayout.LayoutParams.MATCH_PARENT,
            RelativeLayout.LayoutParams.WRAP_CONTENT);
    Lparams.addRule(RelativeLayout.ALIGN_PARENT_LEFT, RelativeLayout.TRUE);
    Lparams.addRule(RelativeLayout.BELOW, txt.getId());
    Lparams.setMargins(10, 0, 0, 0);

    TextView txtS = new TextView(this);
    txtS.setId(y);
    txtS.setText("Test: ");
    txtS.setTextSize(22);

    txtS.setLayoutParams(Lparams);
    txtS.setGravity(Gravity.BOTTOM);
    txtS.setPadding(0, 0, 0, 20);
            rl.addView(txtS);

4) now I want to create the first button:

           Button btnSminus = new Button(this);
    btnSminus.setId(btn1);
    btnSminus.setText("<");
    btnSminus.setTextSize(20);

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

    Lparams.addRule(RelativeLayout.RIGHT_OF, txtS.getId());


    btnSminus.setLayoutParams(Lparams);
            rl.addView(btnSminus);

The problem is, the the button View seems to just disappear from the screen when the line Lparams.addRule(RelativeLayout.RIGHT_OF, txtS.getId()); is executed. What can be the reason?

Answer 1

My guess would be that it's because you set the width of txtS to match_parent , so the button gets pushed off the screen. You can fix that by changing that to wrap_content .