如果你已经在layout(xml)文件中定义了你的视图，并且只想从语法上改变权重，那么创建新的LayoutParams会覆盖在xml文件中定义的其他参数。

所以首先你应该使用"getLayoutParams"然后setLayoutParams

LinearLayout。LayoutParams params = (LinearLayout.LayoutParams) mButton.getLayoutParams(); 参数个数。重量= 4f; mButton.setLayoutParams (params);

使用Kotlin你可以做以下事情:

import android.content.Context
import android.support.v4.content.ContextCompat
import android.support.v7.widget.CardView
import android.widget.*

import android.widget.LinearLayout

class RespondTo : CardView {
    constructor(context: Context) : super(context) {
        init(context)
    }

    private fun init(context: Context) {


        val parent = LinearLayout(context)

        parent.apply {
            layoutParams = LinearLayout.LayoutParams(FrameLayout.LayoutParams.MATCH_PARENT,
                    FrameLayout.LayoutParams.WRAP_CONTENT, 1.0f).apply {
                orientation = LinearLayout.HORIZONTAL

                addView(EditText(context).apply {
                    id = generateViewId()
                    layoutParams = LinearLayout.LayoutParams(0,
                            LinearLayout.LayoutParams.WRAP_CONTENT, 0.9f).apply {
                    }
                })
                addView(ImageButton(context).apply({
                    layoutParams = LinearLayout.LayoutParams(0,
                            LinearLayout.LayoutParams.WRAP_CONTENT, 0.1f)
                    background = null
                    setImageDrawable(ContextCompat.getDrawable(context, R.drawable.ic_save_black_24px))
                    id = generateViewId()
                    layoutParams = RelativeLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,
                            LinearLayout.LayoutParams.WRAP_CONTENT).apply {
                        addRule(RelativeLayout.ALIGN_PARENT_RIGHT)
                        // addRule(RelativeLayout.LEFT_OF, myImageButton.id)
                    }
                }))
            }
        }
        this.addView(parent)
    }
}

如果我有人在寻找答案，用这个:

LinearLayout.LayoutParams lay = (LinearLayout.LayoutParams) myLayout.getLayoutParams();
lay.weight = 0.5;

如果你从xml文件初始化布局，这将比为线性布局提供新的布局参数方便得多。

你可以把它作为LinearLayout的一部分传递进来。LayoutParams构造函数:

LinearLayout.LayoutParams param = new LinearLayout.LayoutParams(
    LayoutParams.MATCH_PARENT,
    LayoutParams.MATCH_PARENT,
    1.0f
);
YOUR_VIEW.setLayoutParams(param);

最后一个参数是权重。

如果你已经在你的layout(xml)文件中定义了你的视图，只想通过编程改变权重，这种方法更好

LinearLayout.LayoutParams params = (LinearLayout.LayoutParams)   
mButton.getLayoutParams();
params.weight = 1.0f;
mButton.setLayoutParams(params);

new a LayoutParams会覆盖xml文件中定义的其他参数，比如页边距，或者你需要在LayoutParams中指定所有的参数。

我已经通过添加这行代码完成了我的任务!

LinearLayout.LayoutParams mylayout = (LinearLayout.LayoutParams)   
myview.getLayoutParams();
mylayout.weight = 2;
myview.setLayoutParams(mylayout);