通過 Java 代碼設定 layout_width 為 50％

參考前文"怎麼設定layout_width為50％", 我們可以設置 <Button> 的重量參數(weight)設定 layout_width 為 50％.

但當我們使用 Java 代碼, 如果定義按鈕的 LayoutParams 為 LayoutParams, 我們是不能設置重量參數(weight)的!

可以把按鈕的 LayoutParams 定義為 LinearLayout.LayoutParams, 便可以通過 new LinearLayout.LayoutParams() 或 LinearLayout.LayoutParams.weight 設置重量參數(weight).

package com.AndroidWeight;

import android.app.Activity;
import android.os.Bundle;
import android.view.ViewGroup.LayoutParams;
import android.widget.Button;
import android.widget.LinearLayout;

public class AndroidWeightActivity extends Activity {
   /** Called when the activity is first created. */
   @Override
   public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
  
  LinearLayout layout = new LinearLayout(getApplicationContext());
  layout.setOrientation(LinearLayout.HORIZONTAL);
  
  // Half Button 1
  LinearLayout subLayout1 = new LinearLayout(getApplicationContext());
  LinearLayout.LayoutParams paramsSubLayout1
   = new LinearLayout.LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT, 1.0f);
  subLayout1.setLayoutParams(paramsSubLayout1);
  subLayout1.setOrientation(LinearLayout.VERTICAL);
  
  Button buttonHalfWidth1 = new Button(getApplicationContext());
  buttonHalfWidth1.setText("Half Width 1");
  LayoutParams paramsHalfWidth1
   = new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);
  buttonHalfWidth1.setLayoutParams(paramsHalfWidth1);
  
  // Half Button 2
  Button buttonHalfWidth2 = new Button(getApplicationContext());
  buttonHalfWidth2.setText("Half Width 2");
  LinearLayout.LayoutParams paramsHalfWidth2
   = new LinearLayout.LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);
  paramsHalfWidth2.weight = 1.0f;
  buttonHalfWidth2.setLayoutParams(paramsHalfWidth2);
    
  //--------
  subLayout1.addView(buttonHalfWidth1);
  layout.addView(subLayout1);
  layout.addView(buttonHalfWidth2);
  
  setContentView(layout);
   }
}