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Android ListView与SQLite综合使用（水果商品展示案例）
首先，看一下主页面。
做一个类似这样的页面，点击+号，输入商品名称，金额，商品就会显示在下面的ListView上，数据是从数据库中获取的。
1、我们先把页面做好。
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.bzu.cyz.fruitlistsqlite.MainActivity">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<EditText
android:id="@+id/ed1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:hint="商品名称"/>
<EditText
android:id="@+id/ed2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:hint="金额"/>
<ImageView
android:id="@+id/add"
android:layout_width="wrap_content"
android:layout_height="25dp"
android:layout_weight="1"
android:onClick="add"
android:src="@drawable/add"/>
</LinearLayout>
<ListView
android:id="@+id/list"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="30dp">
</ListView>
</RelativeLayout> |
2、然后是ListView的item页面
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="wrap_content"
android:paddingBottom="3dp"
android:paddingLeft="10dp"
android:layout_height="wrap_content">
<TextView
android:id="@+id/tv1"
android:layout_margin="20dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="1"
android:textSize="25dp"/>
<TextView
android:id="@+id/tv2"
android:layout_margin="20dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="毛巾"
android:layout_toRightOf="@+id/tv1"
android:textSize="25dp"/>
<TextView
android:id="@+id/tv3"
android:layout_margin="20dp"
android:text="233"
android:textSize="30dp"
android:layout_toRightOf="@+id/tv2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
<ImageView
android:layout_toRightOf="@+id/tv3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:srcCompat="@android:drawable/arrow_up_float"
android:id="@+id/iv1"
android:layout_marginTop="22dp"
android:layout_weight="1" />
<ImageView
android:layout_below="@+id/iv1"
android:layout_toRightOf="@+id/tv3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:srcCompat="@android:drawable/arrow_down_float"
android:id="@+id/iv2"
android:layout_weight="0.17" />
<ImageView
android:onClick="delete"
android:layout_margin="17dp"
android:layout_toRightOf="@+id/iv1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:srcCompat="@android:drawable/ic_menu_delete"
android:id="@+id/iv3"
android:layout_weight="1" />
</RelativeLayout> |
3、然后DbHelper类，创建数据库表。
public class DbHelper extends SQLiteOpenHelper {
public DbHelper(Context context) {
super(context, "fruit.db", null, 2);
}
@Override
public void onCreate(SQLiteDatabase db) {
System.out.println("OnCreate");
db.execSQL("Create TABLE fruit(id INTEGER PRIMARY KEY AUTOINCREMENT,name VARCHAR(20), balance INTEGER)");
}
@Override
public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
System.out.println("OnUpgrade");
}
} |
继承SQLiteOpenHelper，重写下面2个方法。
4、实体类Fruit。
public class Fruit {
private Long id;
private String name;
private int balance;
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getBalance() {
return balance;
}
public void setBalance(int balance) {
this.balance = balance;
}
public Fruit(Long id, String name, int balance) {
super();
this.id = id;
this.name = name;
this.balance = balance;
}
public Fruit(String name, int balance) {
super();
this.name = name;
this.balance = balance;
}
public Fruit() {
super();
}
} |
5、对数据库操作类FruitDao
public class FruitDao {
private DbHelper dbHelper;
public FruitDao(Context context) {
dbHelper =new DbHelper(context);
}
public void insert(Fruit fruit){
SQLiteDatabase db =dbHelper.getWritableDatabase();
ContentValues values =new ContentValues();
values.put("name",fruit.getName());
values.put("balance",fruit.getBalance());
long id = db.insert("fruit",null,values);
fruit.setId(id);
db.close();
}
//根据id删除数据
public int delete(long id){
SQLiteDatabase db =dbHelper.getWritableDatabase();
int count=db.delete("fruit","id=?",new String[]{id+""});
db.close();
return count;
}
public List<Fruit> getAll(){
SQLiteDatabase db =dbHelper.getReadableDatabase();
Cursor c =db.query("fruit",null,null,null,null,null,"balance DESC");
List<Fruit> list =new ArrayList<>();
while (c.moveToNext()){
long id =c.getLong(c.getColumnIndex("id"));
String name = c.getString(1);
int balance =c.getInt(2);
list.add(new Fruit(id,name,balance));
}
c.close();
db.close();
return list;
}
} |
6、如果要把数据显示在ListView上，还要自定义一个适配器FruitAdapter
public class FruitAdapter extends ArrayAdapter<Fruit> {
private int resourceID;
public FruitAdapter(Context context, int resource, List<Fruit> objects) {
super(context, resource, objects);
resourceID =resource;
}
@NonNull
@Override
public View getView(int position, View convertView, ViewGroup parent) {
Fruit fruit = getItem(position);
View view= LayoutInflater.from(getContext()).inflate(resourceID,null);
TextView tv_id = (TextView) view.findViewById(R.id.tv1);
TextView tv_name = (TextView) view.findViewById(R.id.tv2);
TextView tv_price = (TextView) view.findViewById(R.id.tv3);
ImageView imageView1 = (ImageView) view.findViewById(R.id.iv1);
ImageView imageView2 = (ImageView) view.findViewById(R.id.iv2);
ImageView imageView3 = (ImageView) view.findViewById(R.id.iv3);
tv_id.setText(fruit.getId()+"");
tv_name.setText(fruit.getName());
tv_price.setText(fruit.getBalance()+"");
return view;
}
} |
7、最后是MainActivity中
public class MainActivity extends AppCompatActivity {
private List<Fruit> list;
private FruitDao fruidao;
private EditText eName;
private EditText eBalance;
private ListView listView;
private FruitAdapter fruitAdapter;
private Fruit f;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
fruidao =new FruitDao(this);
list=fruidao.getAll();
fruitAdapter =new FruitAdapter(this,R.layout.list_item,list);
listView.setAdapter(fruitAdapter);
}
private void initView() {
listView = (ListView) findViewById(R.id.list);
eName = (EditText) findViewById(R.id.ed1);
eBalance = (EditText) findViewById(R.id.ed2);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
Fruit fruit = (Fruit) adapterView.getItemAtPosition(i);
}
});
}
public void add(View view){
String name =eName.getText().toString();
String balance = eBalance.getText().toString();
f =new Fruit(name,balance.equals("")?0:Integer.parseInt(balance));
fruidao.insert(f);
list.add(f);
fruitAdapter.notifyDataSetChanged();
}
} |
现在添加一条就可以在ListView中显示了 。
————————————————
版权声明：本文为CSDN博主「Zander_Chen」的原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接及本声明。
原文链接：https://blog.csdn.net/chen185597989/article/details/70650034
程序猿的技术大观园：www.javathinker.net
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Java技术网站 → 『 Java开发技术 』 → 『 Android技术专题 』 → Android ListView与SQLite综合使用（水果商品展示案例）
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