Android studio案例Android商城

  本篇文章只是因为做出作业太激动才写的，没什么技术含量，尽量写的通俗易懂一些只是为了能做出来。

1.新建一个新的项目

File-New Project-（取名字）next-next-（选择Empty Activity)next-(取消勾选第二个，如图）Finish

 2.点击app-src-main-res-layout-activity_main.xml

 在左下角Text中复制如下代码（将原本的删掉直接全部复制粘贴就好，复制过去之后Design中会自动出来）

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

    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">


    <TextView
        android:layout_width="match_parent"
        android:layout_height="45dp"
        android:text="购物商城"
        android:textSize="18sp"
        android:textColor="#FFFFFF"
        android:background="#FF8F03"
        android:gravity="center"/>

    <ListView
        android:id="@+id/lv"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</LinearLayout>

3.右键app-src-main-res-layout，选择New-Layout resource file新建一个名为list_item.xml的布局文件

 并在Test中复制如下代码（将原本的删掉直接全部复制粘贴就好）

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="16dp">

    <ImageView
        android:id="@+id/iv"
        android:layout_width="120dp"
        android:layout_height="90dp"
        android:layout_centerVertical="true"/>

    <RelativeLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="10dp"
        android:layout_toRightOf="@+id/iv"
        android:layout_centerVertical="true">

        <TextView
            android:id="@+id/title"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="table"
            android:textSize="20sp"
            android:textColor="#000000" />

        <TextView
            android:id="@+id/tv_price"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="价格"
            android:textSize="20sp"
            android:layout_marginTop="10dp"
            android:layout_below="@id/title"
            android:textColor="#FF8F03" />

        <TextView
            android:id="@+id/price"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="1000"
            android:textSize="20sp"
            android:layout_below="@id/title"
            android:layout_toRightOf="@+id/tv_price"
            android:textColor="#FF8F03"
            android:layout_marginTop="10dp"/>

    </RelativeLayout>
</RelativeLayout>

4.右键app-src-main-res，选择New-Directory

创建一个名为drawable-hdpi的文件夹（此时创建完看不见文件夹需要把左上角切换成Project 

 此刻可以在app-src-main-res看到新创建的文件夹

5.点开我的电脑，搜索drawable-hdpi，并找到此项目对应的文件夹

 将需要的图片拖拽进去，并重命名(只可以使用1-9，a-z，不可使用大写，不可空格），重命名时会弹出一个对话框，点击是

 

 6.打开Android studio,在app-src-main-java-Main Activity中复制如下代码，第一行需要保留Main Activity中自带的（package那行，剩下的可以把原本的删掉，直接复制如下代码）
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;


public class MainActivity extends Activity {
    private String[] titles = {"table", "apple", "cake", "wireclothes", "kiwifruit", "scarf"};
    private String[] prices = {"800元", "10元/kg", "300元", "350元", "10元/kg", "280元"};
    private int[] icons = {R.drawable.table, R.drawable.apple, R.drawable.cake,
            R.drawable.wireclothes, R.drawable.kiwifruit, R.drawable.scarf};

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ListView listView = findViewById(R.id.lv);
        MyBaseAdapter adapter = new MyBaseAdapter();
        listView.setAdapter(adapter);
    }


    class MyBaseAdapter extends BaseAdapter {
        @Override
        public int getCount() {//item总数
            return titles.length;
        }

        @Override
        public Object getItem(int position) { //item数据对象
            return titles[position];
        }

        @Override
        public long getItemId(int position) { // item id
            return position;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) { // view视图
            //将list_item.xml转换为view对象
//            View view = View.inflate(MainActivity.this,R.layout.list_item,null);
//            //初始化控件list_item中的
//            TextView title = view.findViewById(R.id.title);
//            TextView price= view.findViewById(R.id.price);
//            ImageView iv = view.findViewById(R.id.iv);
//            //将数组信息设置在布局中
//            title.setText(titles[position]);
//            price.setText(prices[position]);
//            iv.setImageResource(icons[position]);

            ViewHolder holder = null;
            if (convertView == null) {
                convertView = View.inflate(MainActivity.this, R.layout.list_item, null);
                holder = new ViewHolder();
                holder.title = (TextView) convertView.findViewById(R.id.title);
                holder.price = (TextView) convertView.findViewById(R.id.price);
                holder.iv = (ImageView) convertView.findViewById(R.id.iv);
                convertView.setTag(holder);
            } else {
                holder = (ViewHolder) convertView.getTag();
            }

            holder.title.setText(titles[position]);
            holder.price.setText(prices[position]);
            holder.iv.setBackgroundResource(icons[position]);
            return convertView;

        }

    }

    class ViewHolder {
        TextView title;
        TextView price;
        ImageView iv;

    }
}

然后就可以运行了