测试一下在CSDN博客中插入代码

<LinearLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="2" >

<EditText
android:id="@+id/editScreen"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>

<Button/>

package com.t.layoutdemo1;

import android.app.Activity;
import android.os.Bundle;

public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
}