Android 使用列表处理来自数据库的更新

我在使用列表处理数据库更新时遇到了一个问题，在编辑类中我有这个方法

private ArrayList<store> store_List = new ArrayList<store>();
list = (ListView) findViewById(R.id.list);
list.setOnItemClickListener(new OnItemClickListener() {

    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
        store store = store_List.get(position);
        Intent intent = new Intent(edit.this,Update.class);
        edit.this.finish();
        startActivity(intent);
    }
});

在DB中，方法更新如下：

   public int updatestore(store s) {
    SQLiteDatabase db = this.getWritableDatabase();
    ContentValues values = new ContentValues();
    values.put(KEY_NAME, s.getName());
    values.put(KEY_CATEGORY, s.getCategory());
    return db.update(TABLE_store, values, KEY_ID + " = ?",
            new String[] { String.valueOf(s.getEid()) });
   }

---

您可以将从store_列表中选择的store项传递到Update.class，如下所示：

list = (ListView) findViewById(R.id.list);
list.setOnItemClickListener(new OnItemClickListener() {

    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
        store store = store_List.get(position);
        Intent intent = new Intent(edit.this,Update.class);
        intent.putExtra("myStore", store);
        edit.this.finish();
        startActivity(intent);
    }
});

Store passedStore = getIntent().getSerializableExtra("myStore");

然后在OnClick Listener中，您将拥有以下内容：

btnUpdate.setOnClickListener(new View.OnClickListener() {
    public void onClick(View v) {
        DB db = new DB(getApplicationContext());
        try {
                db.open();
                db.updatestore(passedStore);  //the store item you became as an extra from your intent
                adapter.notifyDataSetChanged();
            } catch (SQLiteException se) {
                Log.e(getClass().getSimpleName(),
                        "Could not create or Open the database");
            } finally {
                if (db != null)
                    db.close();

            }
    }
});

---

你会变成什么样的错误？我没有错误，我只是想知道我应该在db.updatestoreHERE中传递什么；是的，我看到了，等一下，我会给你写我的建议作为回答你的updatestore方法接受一个存储变量。因此，您必须首先在那里传递一个存储变量。更新数据库后，从数据库获取所有数据并将这些值传递给适配器，然后调用yourAdapter.notifyDataSetChanged；非常感谢。当我写入Store passedStore=getIntent.getSerializableExtramyStore时；告诉您将强制转换添加到存储区或将passedScore的类型更改为可序列化时出错。我应该怎么做？在你的Store类中实现Serilizable.try类型转换Store passedStore=StoregetIntent.getSerializableExtramyStore；05-23 13:46:59.979:E/AndroidRuntime20754:java.lang.RuntimeException:无法实例化活动组件{com.example.storesystem/com.example.storesystem.Update}：java.lang.NullPointerException 05-23 13:46:59.979:E/AndroidRuntime20754:at android.app.ActivityThread.performLaunchActivityActivityThread.java:1573 05-23 13:46:59.979:E/AndroidRuntime20754:at android.app.ActivityThread.HandleLaunchActivityThread.java:1667

btnUpdate.setOnClickListener(new View.OnClickListener() {
    public void onClick(View v) {
        DB db = new DB(getApplicationContext());
        try {
                db.open();
                db.updatestore(passedStore);  //the store item you became as an extra from your intent
                adapter.notifyDataSetChanged();
            } catch (SQLiteException se) {
                Log.e(getClass().getSimpleName(),
                        "Could not create or Open the database");
            } finally {
                if (db != null)
                    db.close();

            }
    }
});