android - 我需要从数据库中获取数据并在另一个 Activity 中显示它们

Question

我是 android 编程的新手。我有一个数据库类，其中有名称、公司、位置列。在主要 Activity 中，我有 AutoCompleteTextBox 和一个按钮。例如，如果我在搜索框中输入 SUGAR 并单击搜索按钮，它应该导航到数据库，在下一页上它应该显示为 Name=Sugar, Company=Annapurna, Location=Panjagutta。我完成了我的 DBHelper 类和主 Activity 。但是我无法完成 Second.java 类，即我需要显示数据库中的值的地方......你能帮帮我吗？我附上代码。

DBHelper类如下

    public class ProductDataBase extends SQLiteOpenHelper{
static String db_name="MY_DB";
    static String TABLENAME="Ipay_ReFro_Retailer_Tablet_Details";
    SQLiteDatabase sdb;
    public ProductDataBase(Context context) {
    super(context, db_name, null, 100);
    // TODO Auto-generated constructor stub
    sdb=getWritableDatabase();
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
    // TODO Auto-generated method stub
    db.execSQL("create table if not exists '"+TABLENAME+"'(Name text,Company text,Location text)");
    }
    public void Insertion(){
    sdb.execSQL("insert or replace into '"+TABLENAME+"'  values ('sugar','annapurna','PANJAGUTTA')");
    sdb.execSQL("insert or replace into '"+TABLENAME+"'  values ('salt','annapurna','ECIL')");
    sdb.execSQL("insert or replace into '"+TABLENAME+"'  values ('milk','heritage','BANJARA HILLS')");
    }
    public ArrayList<String> getItemDetails(String itemName){
    ArrayList<String> itemdetails=new ArrayList<String>();
    Cursor c=sdb.rawQuery("select * from '"+TABLENAME+"' where Name='"+itemName+"'", null);
    if(c!=null){
    while(c.moveToNext()){
    String iName=c.getString(c.getColumnIndex("Name"));
    String iCompany=c.getString(c.getColumnIndex("Company"));
    String iLoc=c.getString(c.getColumnIndex("Location"));
    itemdetails.add(iName);
    itemdetails.add(iCompany);
    itemdetails.add(iLoc);
    }
    }
    return itemdetails;
    }
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    // TODO Auto-generated method stub
    }



    }

主要 Activity 如下

    public class TejaShopActivity extends Activity {String[] items=  {"sugar","salt","milk"};
    ProductDataBase pdb;
    String itemName;

    ArrayList<String> a=new ArrayList<String>();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    final AutoCompleteTextView  sp=(AutoCompleteTextView)findViewById(R.id.autoCompleteTextView1);
    Button btn=(Button)findViewById(R.id.button1);
    pdb=new ProductDataBase(this);
    pdb.Insertion();
    ArrayAdapter<String> adapter=new ArrayAdapter<String>(this,     android.R.layout.simple_spinner_dropdown_item,items);
    sp.setAdapter(adapter);
    sp.setOnItemSelectedListener(new OnItemSelectedListener() {

    @Override
    public void onItemSelected(AdapterView<?> parent, View arg1,
    int pos, long arg3) {
    // TODO Auto-generated method stub
    //int id=(int) parent.getItemIdAtPosition(pos);
    itemName=parent.getItemAtPosition(pos).toString();
    Toast.makeText(TejaShopActivity.this,""+itemName, 10).show();
    a=pdb.getItemDetails(itemName);
    }

    @Override
    public void onNothingSelected(AdapterView<?> arg0) {
    // TODO Auto-generated method stub
    } 
    });
    btn.setOnClickListener(new OnClickListener() {
    @Override
    public void onClick(View v) {
    // TODO Auto-generated method stub
    String iname=a.get(0);
    String icompany=a.get(1);
    String iloc=a.get(2);
    //when you are navigating to Second.class get the values from the bundle
    Intent i=new Intent(TejaShopActivity.this,Second.class);
    i.putExtra(iname, "itemName");
    i.putExtra(icompany, "Company");
    i.putExtra(iloc, "Loc");
    startActivity(i);
    }
    }); 
    }

    /*@Override
    public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;*/
    }

我的Second.java如下

    public class Second extends Activity{
TextView tv1,tv2,tv3;
ProductDataBase pdb;
@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.second);

    tv1=(TextView)findViewById(R.id.textView1);
    tv2=(TextView)findViewById(R.id.textView2);
    tv3=(TextView)findViewById(R.id.textView3);

    pdb=new ProductDataBase(this);


    Bundle b=getIntent().getExtras();

    String x=b.getString("itemName");
    String y=b.getString("Company");
    String z=b.getString("Loc");

    tv1.setText(x);
    tv2.setText(y);
    tv3.setText(z);

}

    }

请问你们中的任何人都可以解决这个问题。我在这里被打动了。不知道怎么办？？？

Answer 1

在 TejaShopActivity 中，您的问题在这里:

i.putExtra(iname, "itemName");
i.putExtra(icompany, "Company");
i.putExtra(iloc, "Loc");

你的论点被颠倒了。应该是:

i.putExtra("itemName", iname);
i.putExtra("Company", icompany);
i.putExtra("Loc", iloc);