使用XML和Java代码混合控制UI界面

//activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

<TextView
        style="@style/title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/title"
         app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
    <TextView
        style="@style/h1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/h1"

/>
    <LinearLayout
        style="@style/h1"
        android:orientation="horizontal"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:background="@drawable/background"
        android:id="@+id/layout"
        >
    </LinearLayout>
</android.support.constraint.ConstraintLayout>

//MainActivity.java
package com.dsxfcb.xmlandjava.xmlandjava;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.LinearLayout;

public class MainActivity extends AppCompatActivity {
    private  ImageView[] img=new ImageView[4];		//声明一个保存ImageView组件的数组
    private int[] imagePath=new int[]{
            R.drawable.img01,R.drawable.img04,R.drawable.img03,R.drawable.img02
    };	//声明并初始化一个保存访问图片的数组

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        LinearLayout layout=(LinearLayout)findViewById(R.id.layout);	//获取XML文件中定义的线性布局管理器
        for(int i=0;i<imagePath.length;i++){
            img[i]=new ImageView(this);	//创建一个ImageView组件
            img[i].setImageResource(imagePath[i]);		//为ImageView组件指定要显示的图片
            img[i].setPadding(5, 5, 5, 5);	//设置ImageView组件的内边距
            ViewGroup.LayoutParams params=new ViewGroup.LayoutParams(253,148);		//设置图片的宽度和高度
            img[i].setLayoutParams(params);	//为ImageView组件设置布局参数
            layout.addView(img[i]);	//将ImageView组件添加到布局管理器中
        }

}
}