Android——UI和View——控制方式

控制方式

只用xml实现

<?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>

只用java代码实现

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);
    }
}

二者结合使用

将用xml建的按钮一的Text内容用java代码改变

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");
    }
}