Setting up RelativeLayout in java code

问题:

I'm having a hard time getting two text views to appear on top of each other in my java code. Here's the code I'm experimenting with:

/** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);

        layout = new RelativeLayout(this);
        text1 = new TextView(this);
        text1.setText("1");
        text2 = new TextView(this);
        text2.setText("2");

        RelativeLayout.LayoutParams p = new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT,
                ViewGroup.LayoutParams.WRAP_CONTENT);
        RelativeLayout.LayoutParams q = new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT,
                ViewGroup.LayoutParams.WRAP_CONTENT);

        q.addRule(RelativeLayout.BELOW, layout.getId());
        text1.setLayoutParams(q);
        layout.addView(text1);


        p.addRule(RelativeLayout.BELOW,text1.getId());
        text2.setLayoutParams(p);
        layout.addView(text2);

        setContentView(layout);
    }

This stacks the two text views on the same line, but I want TextView text2, to appear below TextView text1, so in my app I want the following to appear as the output:

1
2

I've tried all sort of things with the "addRule" method, I'm not sure why this isn't working. I want to know how to do this without XML because I plan to build a library of methods that can build up a layout that is easily adjustable through editing an array.

回答1:

Your TextViews don't have an id (by default the id is -1)... put this after their initialization:

text1.setId(1111); // 1111 is just an example,
text2.setId(2222); // just make sure the id are unique

回答2:

I don't think you are looking to layout the text1 view below the RelativeLayout since you added all your views to it as children, right? Try removing the first rule; that rule is asking the text view to be below the same view it is in.

EDIT: Also a help is explicitly setting the id of the view you are laying out relative to.

So here:

text1.setId(2);
p.addRule(RelativeLayout.BELOW,2);

回答3:

you can use xml layout for this :

in relative layout u set the first textview and assign it some id fot the next text view we can assign parameter android:layout_below="id of above text view" in this way we get 2nd text view below 1st text view