如何在代码中设置 RelativeLayout 布局参数，而不是在 xml 中？

例如，我想在屏幕上添加3个按钮: 一个左对齐，一个中心对齐，最后一个右对齐。

我如何设置他们的布局在代码，而不是在 xml？

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最佳答案

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);

正如你所看到的，这是你必须要做的:

  1. 创建一个 RelativeLayout.LayoutParams对象。
  2. 使用 addRule(int)或 addRule(int, int)设置规则。第一个方法用于添加不需要值的规则。
  3. Set the parameters to the view (in this case, to each button).
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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);
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    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);
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如果您创建了布局参数，那么从视图本身中提取布局参数如何。

$((RelativeLayout)findViewById(R.id.imageButton1)).getLayoutParams();
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我希望下面的代码会有所帮助。它将创建一个 EditText 和一个 LogIn 按钮。两者的排名都相对较高。都在 MainActivity.java 中完成。

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);
}
}

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