基于android studio开发的校园二手交易平台APP+源代码+文档说明（毕业设计&期末大作业）

package page.page1; import android.content.DialogInterface; import android.content.Intent; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.util.Log; import android.view.View; import android.view.ViewGroup; import android.widget.AdapterView; import android.widget.BaseAdapter; import android.widget.ImageButton; import android.widget.ImageView; import android.widget.LinearLayout; import android.widget.ListView; import android.widget.RadioButton; import android.widget.RadioGroup; import android.widget.SimpleAdapter; import android.widget.TextView; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; public class main_page extends AppCompatActivity implements View.OnClickListener{ String TABLENAME = "iteminfo"; Intent intent; byte[] imagedata; Bitmap imagebm; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main_page); DatabaseHelper database = new DatabaseHelper(this); final SQLiteDatabase db = database.getWritableDatabase(); ListView listView = (ListView)findViewById(R.id.listView); Map<String, Object> item; // 列表项内容用Map存储 final List<Map<String, Object>> data = new ArrayList<Map<String, Object>>(); // 列表 Cursor cursor = db.query(TABLENAME,null,null,null,null,null,null,null); // 数据库查询 if (cursor.moveToFirst()){ while (!cursor.isAfterLast()){ item = new HashMap<String, Object>(); // 为列表项赋值 item.put("id",cursor.getInt(0)); item.put("userid",cursor.getString(1)); item.put("title",cursor.getString(2)); item.put("kind",cursor.getString(3)); item.put("info",cursor.getString(4)); item.put("price",cursor.getString(5)); imagedata = cursor.getBlob(6); imagebm = BitmapFactory.decodeByteArray(imagedata, 0, imagedata.length); item.put("image",imagebm); cursor.moveToNext(); data.add(item); // 加入到列表中 } } /* item = new HashMap<String, Object>(); item.put("userid","ysh"); item.put("image", R.drawable.buy_item1); item.put("title","一个九成新的篮球"); item.put("kind","体育用品"); item.put("info", "刚买没多久，希望转卖出去..."); item.put("price", "59元"); data.add(item); item = new HashMap<String, Object>(); item.put("userid","xg"); item.put("image", R.drawable.buy_item2); item.put("title","一个八成新的篮球"); item.put("kind","体育用品"); item.put("info", "刚买没多久，希望转卖出去..."); item.put("price", "59元"); data.add(item); item = new HashMap<String, Object>(); item.put("userid","hdq"); item.put("image", R.drawable.buy_item3); item.put("title","一个八成新的篮球"); item.put("kind","体育用品"); item.put("info", "刚买没多久，希望转卖出去..."); item.put("price", "59元"); data.add(item); */ // 使用SimpleAdapter布局listview SimpleAdapter simpleAdapter = new SimpleAdapter(this, data, R.layout.listitem, new String[] { "image", "title", "kind", "info", "price" }, new int[] { R.id.item_image, R.id.title, R.id.kind, R.id.info, R.id.price }); simpleAdapter.setViewBinder(new SimpleAdapter.ViewBinder() { @Override public boolean setViewValue(View view, Object data, String textRepresentation) { if(view instanceof ImageView && data instanceof Bitmap){ ImageView iv = (ImageView)view; iv.setImageBitmap( (Bitmap)data ); return true; }else{ return false; } } }); listView.setAdapter(simpleAdapter); ImageView kind1 = (ImageView) findViewById(R.id.kind1); kind1.setOnClickListener(this); ImageView kind2 = (ImageView) findViewById(R.id.kind2); kind2.setOnClickListener(this); ImageView kind3 = (ImageView) findViewById(R.id.kind3); kind3.setOnClickListener(this); ImageView kind4 = (ImageView) findViewById(R.id.kind4); kind4.setOnClickListener(this); // 为列表项设置监听器 listView.setOnItemClickListener(new AdapterView.OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { intent = new Intent(main_page.this, item_info.class); intent.putExtra("id", data.get(position).get("id").toString()); // 获取该列表项的key为id的键值，即商品的id，将其储存在Bundle传递给打开的页面 startActivity(intent); } }); RadioButton btn1 = (RadioButton)findViewById(R.id.button_1); RadioButton btn2 = (RadioButton)findViewById(R.id.button_2); RadioButton btn3 = (RadioButton)findViewById(R.id.button_3); btn1.setOnClickListener(this); btn2.setOnClickListener(this); btn3.setOnClickListener(this); } @Override public void onClick(View v){ switch (v.getId()){ case R.id.kind1: Intent KindIntent1 = new Intent(this,kind_page1.class); startActivity(KindIntent1); break; case R.id.kind2: Intent KindIntent2 = new Intent(this,kind_page2.class); startActivity(KindIntent2); break; case R.id.kind3: Intent KindIntent3 = new Intent(this,kind_page3.class); startActivity(KindIntent3); break; case R.id.kind4: Intent KindIntent4 = new Intent(this,kind_page4.class); startActivity(KindIntent4); break; case R.id.button_1: Intent button1 = new Intent(main_page.this,main_page.class); startActivity(button1); break; case R.id.button_2: Intent button2 = new Intent(this,AddItem.class); startActivity(button2); break; case R.id.button_3: Intent button3 = new Intent(this,MyselfActivity.class); startActivity(button3); break; } } }