How to set RelativeLayout layout params in code not in xml?

For example I want to add 3 buttons on screen: one align left, 开发者_如何学编程one align center, last one align right.

How can I set their layout in code, not in xml?

Just a basic example:

RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
params.addRule(RelativeLayout.ALIGN_PARENT_LEFT, RelativeLayout.TRUE);
Button button1;
button1.setLayoutParams(params);

params = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
params.addRule(RelativeLayout.RIGHT_OF, button1.getId());
Button button2;
button2.setLayoutParams(params);

As you can see, this is what you have to do:

1. Create a RelativeLayout.LayoutParams object.
2. Use addRule(int) or addRule(int, int) to set the rules. The first method is used to add rules that don't require values.
3. Set the parameters to the view (in this case, to each button).

    RelativeLayout layout = new RelativeLayout(this);
    RelativeLayout.LayoutParams labelLayoutParams = new RelativeLayout.LayoutParams(
            LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);
    layout.setLayoutParams(labelLayoutParams);


   // If you want to add some controls in this Relative Layout
    labelLayoutParams = new RelativeLayout.LayoutParams(
            LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
    labelLayoutParams.addRule(RelativeLayout.CENTER_IN_PARENT);


    ImageView mImage = new ImageView(this);
    mImage.setBackgroundResource(R.drawable.popupnew_bg);        
    layout.addView(mImage,labelLayoutParams);

    setContentView(layout);

Something like this..

 RelativeLayout linearLayout = (RelativeLayout) findViewById(R.id.widget43);
                // ListView listView = (ListView) findViewById(R.id.ListView01);

                LayoutInflater inflater = (LayoutInflater) this
                        .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                // View footer = inflater.inflate(R.layout.footer, null);
                View footer = LayoutInflater.from(this).inflate(R.layout.footer,
                        null);
                final RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(
                        RelativeLayout.LayoutParams.FILL_PARENT,
                        RelativeLayout.LayoutParams.FILL_PARENT);
                layoutParams.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM, 1);
footer.setLayoutParams(layoutParams);

How about you just pull the layout params from the view itself if you created it.

$((RelativeLayout)findViewById(R.id.imageButton1)).getLayoutParams();

I hope the below code will help. It will create an EditText and a Log In button. Both placed relatively. All done in MainActivity.java.

package com.example.atul.allison;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.RelativeLayout;
import android.widget.Button;
import android.graphics.Color;
import android.widget.EditText;
import android.content.res.Resources;
import android.util.TypedValue;     
    public class MainActivity extends AppCompatActivity {

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            //Layout
            RelativeLayout atulsLayout = new RelativeLayout(this);
            atulsLayout.setBackgroundColor(Color.GREEN);

            //Button
            Button redButton = new Button(this);
            redButton.setText("Log In");
            redButton.setBackgroundColor(Color.RED);

            //Username input
            EditText username =  new EditText(this);

            redButton.setId(1);
            username.setId(2);

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

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

            //give rules to position widgets
            usernameDetails.addRule(RelativeLayout.ABOVE,redButton.getId());
            usernameDetails.addRule(RelativeLayout.CENTER_HORIZONTAL);
            usernameDetails.setMargins(0,0,0,50);

            buttonDetails.addRule(RelativeLayout.CENTER_HORIZONTAL);
            buttonDetails.addRule(RelativeLayout.CENTER_VERTICAL);

            Resources r = getResources();
            int px = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 200,r.getDisplayMetrics());
            username.setWidth(px);

            //Add widget to layout(button is now a child of layout)
            atulsLayout.addView(redButton,buttonDetails);
            atulsLayout.addView(username,usernameDetails);

            //Set these activities content/display to this view
            setContentView(atulsLayout);
        }
    }