第十一个作业
MainActivity.java 代码:
public class MainActivity extends ActionBarActivity { private EditText etName, etPrice, etNumber; private ListView listView; private String name, price, number; private MyHelper myHelper; private SQLiteDatabase db; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); myHelper = new MyHelper(this); init(); } public void click(View v) { ContentValues values; // 创建ContentValues对象 switch (v.getId()) { case R.id.button1: name = etPrice.getText().toString(); price = etName.getText().toString(); number = etNumber.getText().toString(); db = myHelper.getWritableDatabase(); values = new ContentValues(); values.put("name", name); // 将数据添加到ContentValues对象 values.put("price", price); values.put("number", number); db.insert("cart", null, values); db.close(); Toast.makeText(this, "信息已添加", Toast.LENGTH_SHORT).show(); break; case R.id.button2: Log.e("yanwenhua", "123"); List<Commodity> list = new ArrayList(); db = myHelper.getWritableDatabase(); Cursor cursor = db .query("cart", null, null, null, null, null, null); if (cursor.getCount() == 0) { Toast.makeText(this, "没有数据", Toast.LENGTH_SHORT).show(); } else { while (cursor.moveToNext()) { Commodity commodity = new Commodity(); int nameIndex = cursor.getColumnIndex("name"); int priceIndex = cursor.getColumnIndex("price"); int numberIndex = cursor.getColumnIndex("number"); String name = cursor.getString(nameIndex); String price = cursor.getString(priceIndex); String number = cursor.getString(numberIndex); Log.e("yanwenhua", "cursor.getCount();--" + cursor.getCount() + "name-" + name + " " + price + " " + number); commodity.setName(name); commodity.setPrice(price); commodity.setNumber(number); list.add(commodity); } MyBaseAdapter adapter = new MyBaseAdapter(MainActivity.this, list); listView.setAdapter(adapter); adapter.notifyDataSetChanged(); } cursor.close(); db.close(); break; case R.id.button3: name = etPrice.getText().toString(); price = etName.getText().toString(); number = etNumber.getText().toString(); db = myHelper.getWritableDatabase(); values = new ContentValues(); // 要修改的数据 values.put("number",number); values.put("price",price); db.update("cart", values, "name=?", new String[]{name}); // 更新并得到行数 db.close(); Toast.makeText(this, "信息已修改", Toast.LENGTH_SHORT).show(); break; case R.id.button4: db = myHelper.getWritableDatabase(); db.delete("cart", null, null); List<Commodity> list2 = new ArrayList(); MyBaseAdapter adapter = new MyBaseAdapter(MainActivity.this,list2); listView.setAdapter(adapter); adapter.notifyDataSetChanged(); db.close(); Toast.makeText(this, "信息已删除", Toast.LENGTH_SHORT).show(); break; } } private void init() { setContentView(R.layout.activity_main); etName = (EditText) findViewById(R.id.editText2); etPrice = (EditText) findViewById(R.id.editText1); etNumber = (EditText) findViewById(R.id.editText3); listView = (ListView) findViewById(R.id.listView); Button add = (Button) findViewById(R.id.button1); Button query = (Button) findViewById(R.id.button2); Button update = (Button) findViewById(R.id.button3); Button delete = (Button) findViewById(R.id.button4); } class MyBaseAdapter extends BaseAdapter { private List<Commodity> list; private LayoutInflater layoutInflater; public MyBaseAdapter(Context context, List<Commodity> list){ this.layoutInflater = LayoutInflater.from(context); this.list = list; } @Override public int getCount() { Log.e("yanwenhua","list.size()--"+list.size()); return list.size(); } @Override public Object getItem(int position) { return null; } @Override public long getItemId(int position) { return 0; } @Override public View getView(int position, View convertView, ViewGroup parent) { ViewHolder viewHolder; if (convertView==null){ convertView=layoutInflater.inflate(R.layout.list_item,null); viewHolder=new ViewHolder(convertView); convertView.setTag(viewHolder); }else { viewHolder=(ViewHolder) convertView.getTag(); } Commodity commodity = list.get(position); viewHolder.tv_name.setText("商品名称:"+commodity.getName()); viewHolder.tv_price.setText("商品价格:"+commodity.getPrice()); viewHolder.tv_number.setText("商品数量:"+commodity.getNumber()); Log.e("yanwenhua","cartBean.getName()-"+commodity.getName()+" "+commodity.getPrice()+" "+commodity.getNumber()); return convertView; } class ViewHolder{ TextView tv_name; TextView tv_price; TextView tv_number; public ViewHolder(View view){ tv_name = (TextView) view.findViewById(R.id.textView1); tv_price = (TextView) view.findViewById(R.id.textView2); tv_number = (TextView) view.findViewById(R.id.textView3); } } } }
MyHepler.java 代码:
public class MyHelper extends SQLiteOpenHelper { public MyHelper(Context context) { super(context, "shoppingcart.db", null, 1); } @Override public void onCreate(SQLiteDatabase db) { db.execSQL("CREATE TABLE cart(_id INTEGER PRIMARY KEY AUTOINCREMENT, name VARCHAR(20), price VARCHAR(20), number VARCHAR(20))"); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { } }
Commodity.java 代码:
public class Commodity { private String name; private String price; private String number; public String getName() { return name; } public void setName(String name) { this.name = name; } public String getPrice() { return price; } public void setPrice(String price) { this.price = price; } public String getNumber() { return number; } public void setNumber(String number) { this.number = number; } }
activity_main.xml 代码:
<LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="15dp" android:background="@android:color/white" android:orientation="horizontal" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:padding="10dp" android:text="名称:" android:textColor="#000" android:textSize="20sp" /> <EditText android:id="@+id/editText1" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginLeft="5dp" android:background="@null" android:maxLines="1" android:padding="10dp" /> </LinearLayout> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="15dp" android:background="@android:color/white" android:orientation="horizontal" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:padding="10dp" android:text="价格:" android:textColor="#000" android:textSize="20sp" /> <EditText android:id="@+id/editText2" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginLeft="5dp" android:background="@null" android:maxLines="1" android:padding="10dp" /> </LinearLayout> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:background="@android:color/white" android:orientation="horizontal" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:padding="10dp" android:text="数量:" android:textColor="#000" android:textSize="20sp" /> <EditText android:id="@+id/editText3" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginLeft="5dp" android:background="@null" android:maxLines="1" android:padding="10dp" /> </LinearLayout> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:orientation="horizontal" > <Button android:id="@+id/button1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:onClick="click" android:text="添加" /> <Button android:id="@+id/button2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:onClick="click" android:text="查询" /> <Button android:id="@+id/button3" android:layout_width="wrap_content" android:layout_height="wrap_content" android:onClick="click" android:text="修改" /> <Button android:id="@+id/button4" android:layout_width="wrap_content" android:layout_height="wrap_content" android:onClick="click" android:text="删除" /> </LinearLayout> <ListView android:id="@+id/listView" android:layout_width="wrap_content" android:layout_height="wrap_content" android:background="#ffffff" > </ListView>
list_item.xml 代码:
<TextView android:id="@+id/textView1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:textSize="15sp"/> <TextView android:id="@+id/textView2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="3dp" android:textSize="15sp"/> <TextView android:id="@+id/textView3" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="3dp" android:textSize="15sp"/>