Android基础知识【项目实训-实现二级导航“今日活动”及读取数据库】【5】

【该项目实训是Android基础知识的一个综合练习，特别提示：项目中会用到一些图片素材，都是随意整理的，稍后会上传一个资源，包含该事项项目的基本功能，也含有图片素材】

【项目题目】：校园订餐App设计

综合案例
【目标】
主界面中包含两个二级子界面，分别是活动界面和账单界面，下面介绍它们的实现代码和布局文件。

1、下面这个是 活动界面的Activity代码，因为这个界面加载时需要 读取数据库中数据了，所有功能的实现上会涉及到 db那个包中一些类。

注意这个Activity也是继承 ActivityGroup的

public class DiscountFoodActivity extends ActivityGroup implements OnItemClickListener {
TabHost innerTab;
ListView promotionFoodList,discountFoodList;
//促销列表数据，
List<FoodInfo> pdata;
//折扣列表数据
List<FoodInfo> ddata;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_discount_food);
promotionFoodList=(ListView) findViewById(R.id.promotionFoodList);
discountFoodList=(ListView) findViewById(R.id.discountFoodList);
innerTab=(TabHost) findViewById(R.id.innerTab_discount);
//初始化的内部Tab
initInnerTabHost();
initListView();	//初始化列表数据
//添加监听器，监听列表项的点击
promotionFoodList.setOnItemClickListener(this);
discountFoodList.setOnItemClickListener(this);
}
//初始化活动食品列表 和 折扣食品列表
private void initListView() {
//获取数据库
EatDbHelper dbh=new EatDbHelper(this,"fooddb.db3",null,1);
SQLiteDatabase db =dbh.getReadableDatabase();
pdata =new FoodDao().queryFood(db,
"ispromotion=?", new String[]{"1"}, "price DESC");
FoodListAdapter fla =new FoodListAdapter(
this,pdata,R.layout.foodlist_item);
promotionFoodList.setAdapter(fla);

ddata =new FoodDao().queryFood(db,
"discount<?", new String[]{"1"}, "price DESC");
fla =new FoodListAdapter(
this,ddata,R.layout.foodlist_item);
discountFoodList.setAdapter(fla);

}
private void initInnerTabHost() {
innerTab.setup(getLocalActivityManager());
TabSpec t1=innerTab.newTabSpec("inner_dis_t1");
t1.setIndicator("今日活动", getResources().getDrawable(R.drawable.ic_launcher));
t1.setContent(R.id.innerTab_discount_tab1);

TabSpec t2=innerTab.newTabSpec("inner_dis_t2");
t2.setIndicator("今日折扣", getResources().getDrawable(R.drawable.ic_launcher));
t2.setContent(R.id.innerTab_discount_tab2);

innerTab.addTab(t1);
innerTab.addTab(t2);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.discount_food, menu);
return true;
}
@Override
public void onItemClick(AdapterView<?> lv, View view, int index, long arg3) {
Intent intent =new Intent(this,FoodDetailActivity.class);
Bundle bd =new Bundle();
//Log.i("Msg", "当前点击列表"+lv + "  "+lv.getId());
if(lv.getId()==R.id.promotionFoodList){
bd.putSerializable("food",pdata.get(index));
//Log.i("Msg", "当前选择："+pdata.get(index).getFoodName());
}else if(lv.getId()==R.id.discountFoodList){
bd.putSerializable("food",ddata.get(index));
//Log.i("Msg", "当前选择："+ddata.get(index).getFoodName());
}
intent.putExtras(bd);
startActivity(intent);
}

}

2、布局界面，项目中用到很多资源，现在把这些资源的结果 展示一下。





活动Activity使用的界面是activity_discount_food.xml，代码是：

<RelativeLayout 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=".DiscountFoodActivity" >

<TabHost
android:id="@+id/innerTab_discount"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >

<TabWidget
android:id="@android:id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
</TabWidget>
<FrameLayout
android:id="@android:id/tabcontent"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<LinearLayout
android:id="@+id/innerTab_discount_tab1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
>
<ListView
android:id="@+id/promotionFoodList"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
</ListView>
</LinearLayout>
<LinearLayout
android:id="@+id/innerTab_discount_tab2"
android:layout_width="match_parent"
android:orientation="vertical"
android:layout_height="match_parent" >
<ListView
android:id="@+id/discountFoodList"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
</ListView>
</LinearLayout>
</FrameLayout>
</LinearLayout>
</TabHost>

</RelativeLayout>

其实这也是一个tab导航，只是它的标签导航在上面。

3、因为要读取活动和折扣 食物数据，因此准备了两个集合

//促销列表数据，
List<FoodInfo> pdata;
//折扣列表数据
List<FoodInfo> ddata;

这里的FoodInf是一个实体类，请留意对属性的注释。

package com.example.entity;

import java.io.Serializable;

import android.graphics.Bitmap;

public class FoodInfo implements Serializable {
private String _id,foodName;
private String price;
private String isPromotion;	//菜品是否促销活动 1 有活动， 0 没有活动
private String discount="1";	//折扣
private String category;	//食物所属类别，主食、配菜、饮料，其他四类
private String type;	//菜系，酸甜苦辣咸等，鲁粤川苏等
private String score;	//菜品累计得分
private int shopId;	//餐馆ID
private ShopInfo shop;	//食物所属餐馆
private Bitmap img;
private String imgId;
private String description;	//关于食物的描述

public String getFoodName() {
return foodName;
}
public void setFoodName(String foodName) {
this.foodName = foodName;
}
public String getPrice() {
return price;
}
public void setPrice(String price) {
this.price = price;
}
public String getCategory() {
return category;
}
public void setCategory(String category) {
this.category = category;
}
public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
public String getScore() {
return score;
}
public void setScore(String score) {
this.score = score;
}
public ShopInfo getShop() {
return shop;
}
public void setShop(ShopInfo shop) {
this.shop = shop;
}
public String get_id() {
return _id;
}
public void set_id(String _id) {
this._id = _id;
}
public int getShopId() {
return shopId;
}
public void setShopId(int shopId) {
this.shopId = shopId;
}
public String getIsPromotion() {
return isPromotion;
}
public void setIsPromotion(String isPromotion) {
this.isPromotion = isPromotion;
}
public String getDiscount() {
return discount;
}
public void setDiscount(String discount) {
this.discount = discount;
}
public Bitmap getImg() {
return img;
}
public void setImg(Bitmap img) {
this.img = img;
}
public String getImgId() {
return imgId;
}
public void setImgId(String imgId) {
this.imgId = imgId;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
@Override
public String toString() {
return "FoodInfo [_id=" + _id + ", foodName=" + foodName + ", price="
+ price + ", isPromotion=" + isPromotion + ", discount="
+ discount + ", category=" + category + ", type=" + type
+ ", score=" + score + ", shopId=" + shopId + ", shop=" + shop
+ ", img=" + img + ", imgId=" + imgId + "]";
}

}

4、上面的俩集合中的数据是靠 db中的类给填充的。

pdata =new FoodDao().queryFood(db,
"ispromotion=?", new String[]{"1"}, "price DESC");

FoodDao就是一个专门读取 食物数据的类，其代码如下：

public class FoodDao {

public List<FoodInfo> queryFood(SQLiteDatabase db,String sel,String []selArg,String order){
List<FoodInfo> fs=new ArrayList<FoodInfo>();
Cursor c=db.query("tb_foodInfo",
new String[]{"_id","foodName","category","type","price",
"score","imgId","shopId","discount","isPromotion"},
sel,selArg,null,null,order);
Log.i("Msg", "读取记录条数 ："+c.getCount());
c.moveToFirst();
while(!c.isAfterLast()){
FoodInfo f =new FoodInfo();
f.set_id(c.getString(0));
f.setFoodName(c.getString(1));
f.setCategory(c.getString(2));
f.setType(c.getString(3));
f.setPrice(c.getString(4));
f.setScore(c.getString(5));
String imgId=c.getString(6);
f.setImgId(Integer.parseInt(imgId.substring(2),16)+"");
f.setShopId(c.getInt(7));
f.setDiscount(c.getString(8));
f.setIsPromotion(c.getString(9));
//Log.i("Msg", f.toString());
fs.add(f);
c.moveToNext();
}
c.close();
return fs;
}

}

5、读取完数据了，就可以采用适配器 把数据绑定到 列表上了。

FoodListAdapter fla =new FoodListAdapter(

this,pdata,R.layout.foodlist_item);

FoodListAdapter是一个继承了BaseAdapter的适配器。（ 容易理解期间，这个适配器写的并不通用，但应该容易理解了）

代码如下：

public class FoodListAdapter extends BaseAdapter {
private Context context;
private List<FoodInfo> data;
private int layout;

public FoodListAdapter(Context context, List<FoodInfo> data, int layout) {
super();
this.context = context;
this.data = data;
this.layout = layout;
}
@Override
public int getCount() {
return data.size();
}
@Override
public Object getItem(int arg0) {
// TODO Auto-generated method stub
return data.get(arg0);
}
@Override
public long getItemId(int arg0) {
// TODO Auto-generated method stub
return arg0;
}
@Override
public View getView(int index, View arg1, ViewGroup arg2) {
LayoutInflater inflater =LayoutInflater.from(context);
View v =inflater.inflate(layout, null);
ImageView iv =(ImageView) v.findViewById(R.id.foodlist_item_img);
iv.setImageResource(Integer.parseInt(data.get(index).getImgId()));
TextView name=(TextView) v.findViewById(R.id.foodlist_item_name);
name.setText(data.get(index).getFoodName());
TextView category=(TextView) v.findViewById(R.id.foodlist_item_category);
category.setText(data.get(index).getCategory());
TextView type=(TextView) v.findViewById(R.id.foodlist_item_type);
type.setText(data.get(index).getType());
TextView price=(TextView) v.findViewById(R.id.foodlist_item_price);
price.setText("￥"+data.get(index).getPrice());
float zk =Float.parseFloat(data.get(index).getDiscount());
if(zk<1){
TextView discount=(TextView) v.findViewById(R.id.foodlist_item_discount);
discount.setText("折扣:"+(zk*10)+"折");
}
TextView score=(TextView) v.findViewById(R.id.foodlist_item_score);
score.setText("百米分:"+data.get(index).getScore()+"米");
return v;
}

}

6、其中 列表

ListView promotionFoodList,discountFoodList;

它们的列表项布局是一样的，统一采用布局文件：

</pre><pre code_snippet_id="563089" snippet_file_name="blog_20141226_11_5643964" name="code" class="java"><pre name="code" class="html"><?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<ImageView
android:id="@+id/foodlist_item_img"
android:layout_width="60dp"
android:layout_height="60dp"
android:background="@drawable/imgbg"
android:src="@drawable/food_02" />
<TextView
android:id="@+id/foodlist_item_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toRightOf="@id/foodlist_item_img"
android:layout_marginLeft="8dp"
android:text="菜品"
android:textAppearance="?android:attr/textAppearanceLarge" />
<TextView
android:id="@+id/foodlist_item_category"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toRightOf="@id/foodlist_item_name"
android:layout_marginLeft="8dp"
android:text="中餐"
android:textAppearance="?android:attr/textAppearanceMedium" />
<TextView
android:id="@+id/foodlist_item_type"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toRightOf="@id/foodlist_item_category"
android:layout_marginLeft="8dp"
android:text="酸辣"
android:textAppearance="?android:attr/textAppearanceMedium" />
<TextView
android:id="@+id/foodlist_item_price"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/foodlist_item_name"
android:layout_alignLeft="@id/foodlist_item_name"
android:layout_marginTop="8dp"
android:text="￥10.00"
android:textAppearance="?android:attr/textAppearanceSmall" />
<TextView
android:id="@+id/foodlist_item_discount"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toRightOf="@id/foodlist_item_price"
android:layout_alignBottom="@id/foodlist_item_price"
android:layout_marginLeft="8dp"
android:text=""
android:textAppearance="?android:attr/textAppearanceSmall" />
<TextView
android:id="@+id/foodlist_item_score"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toRightOf="@id/foodlist_item_discount"
android:layout_alignBottom="@id/foodlist_item_discount"
android:layout_alignParentRight="true"
android:layout_marginRight="8dp"
android:gravity="right"
android:text="评分：122"
android:textAppearance="?android:attr/textAppearanceSmall" />

</RelativeLayout>

折扣界面说完，下一篇说 账单界面。