Android——UI和View——控制方式

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"

tools:context="com.example.chenshuai.test322.MainActivity"
android:orientation="vertical">
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="按钮一"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="按钮二"
android:id="@+id/button"/>

</LinearLayout>

package com.example.chenshuai.test322;

import android.os.Bundle;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.AppCompatActivity;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.LinearLayout;

/**
* Created by chenshuai on 2016/3/22.
*/
public class Activity1 extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);

//创建布局管理器  线性布局 将线性布局放入Activity里
LinearLayout linearLayout = new LinearLayout(this);

linearLayout.setOrientation(LinearLayout.VERTICAL);

linearLayout.setLayoutParams(new DrawerLayout.LayoutParams(
ViewGroup.LayoutParams.MATCH_PARENT,
ViewGroup.LayoutParams.MATCH_PARENT));

Button button = new Button(this);

button.setText("按钮三");

button.setLayoutParams(new DrawerLayout.LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT));

//把View（按钮）放到布局（LinearLayout）里
linearLayout.addView(button);

//关联布局管理器
setContentView(linearLayout);
}
}

package com.example.chenshuai.test322;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.Button;

public class MainActivity extends AppCompatActivity {

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

Button button = (Button)findViewById(R.id.button2);

button.setText("新按钮名称");
}
}