我正在使用列表视图 Activity 将数据发送到编辑数据 Activity，这里有什么问题？

Question

我正在从数据库中检索项目名称、项目描述和项目价格，当用户单击项目时，它将进入编辑 activity，用户可以在其中更新或删除数据，但是当我单击列表时它带我回到主要项目 Activity

当用户点击查看数据时，显示列表视图单击列表视图后，用户应移至编辑数据 activity，其中编辑数据 activity 数据将显示在编辑文本框中以供更新或删除

我的代码运行使用一个参数项目名称没问题，但是当我使用项目描述和项目价格时，出现此错误

private static final String TAG = "ListDataActivity";

DatabaseHelper mDatabaseHelper;

private ListView mListView;

@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_list_data);
    mListView = (ListView) findViewById(R.id.listView);
    mDatabaseHelper = new DatabaseHelper(this);

    populateListView();
}

private void populateListView() {
    Log.d(TAG, "populateListView: Displaying data in the ListView.");

    Cursor data = mDatabaseHelper.getData();
    ArrayList<String> listData = new ArrayList<>();
    while(data.moveToNext()){
        listData.add(data.getString(1));
    }
    ListAdapter adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, listData);
    mListView.setAdapter(adapter);
    mListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {

            String name = adapterView.getItemAtPosition(i).toString();
            String des = adapterView.getItemAtPosition(i).toString();
            String pri = adapterView.getItemAtPosition(i).toString();

            Log.d(TAG, "onItemClick: You Clicked on " + name);

            Cursor data = mDatabaseHelper.getItemID(name, des, pri); //get the id associated with that name
            int itemID = -1;
            while(data.moveToNext()){
                itemID = data.getInt(0);
            }
            if(itemID > -1){
                Log.d(TAG, "onItemClick: The ID is: " + itemID);
                Intent intent = new Intent(ListDataActivity.this, EditDataActivity.class);
                Bundle extras = new Bundle();
                extras.putInt("id",itemID);
                extras.putString("name",name);
                extras.putString("description",des);
                extras.putString("price",pri);
                intent.putExtras(extras);

                startActivity(intent);
            }
            else{
                toastMessage("No ID associated with that name");
            }
        }
    });
}


private void toastMessage(String message){
    Toast.makeText(this,message, Toast.LENGTH_SHORT).show();
}

新的更新代码，我做了以下更改

    package com.example.saveanddisplaysql;


    import android.content.Intent;
    import android.database.Cursor;
    import android.os.Bundle;
    import android.support.annotation.Nullable;
    import android.support.v7.app.AppCompatActivity;
    import android.util.Log;
    import android.view.View;
    import android.widget.AdapterView;
    import android.widget.ArrayAdapter;
    import android.widget.ListAdapter;
    import android.widget.ListView;
    import android.widget.Toast;

    import java.util.ArrayList;



    public class ListDataActivity extends AppCompatActivity {

        private static final String TAG = "ListDataActivity";

        DatabaseHelper mDatabaseHelper;

        private ListView mListView;

        @Override
        protected void onCreate(@Nullable Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_list_data);
            mListView = (ListView) findViewById(R.id.listView);
            mDatabaseHelper = new DatabaseHelper(this);

            populateListView();
        }

        private void populateListView() {
            Log.d(TAG, "populateListView: Displaying data in the ListView.");

            Cursor data = mDatabaseHelper.getData();
            class Model {
                String name;
                String desc;
                int price;
            }
            ArrayList< Model> listData = new ArrayList<>();

            while(data.moveToNext()){ 
            Model model = new Model();
            model.name = data.getString(1); 
            model.desc = data.getString(2); 
            model.price = data.getInt(3); 
            listData.add(model); }
            ListAdapter adapter = new ArrayAdapter<>(this, 
            android.R.layout.simple_list_item_1, listData);
            mListView.setAdapter(adapter);
            mListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                @Override
                public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {

                    Model model = (Model)adapterView.getItemAtPosition(i);
            String name = model.name;
            String des = model.des;
            String pri = model.pri;

            Log.d(TAG, "onItemClick: You Clicked on " + name);

            Cursor data = mDatabaseHelper.getItemID(name, des, pri); //get the id associated with these
                    int itemID = -1;
                    while(data.moveToNext()){
                        itemID = data.getInt(0);
                    }
                    if(itemID > -1){
                        Log.d(TAG, "onItemClick: The ID is: " + itemID);
                        Intent intent = new Intent(ListDataActivity.this, EditDataActivity.class);
                        Bundle extras = new Bundle();
                        extras.putInt("id",itemID);
                        extras.putString("name",name);
                        extras.putString("description",des);
                        extras.putString("price",pri);
                        intent.putExtras(extras);

                        startActivity(intent);
                    }
                    else{
                        toastMessage("No ID associated with that name");
                    }
                }
            });
        }


        private void toastMessage(String message){
            Toast.makeText(this,message, Toast.LENGTH_SHORT).show();
        }
    }

Logcat:

2019-04-11 10:51:34.331 32717-32717/? I/art: 延迟启用 -Xcheck:jni 2019-04-11 10:51:34.351 32717-32717/? D/TidaProvider: TidaProvider() 2019-04-11 10:51:34.364 32717-32717/com.example.saveanddisplaysql W/ReflectionUtils: java.lang.NoSuchMethodException: android.os.MessageQueue#enableMonitor()#bestmatch 在 miui.util.ReflectionUtils.findMethodBestMatch(ReflectionUtils.java:338) 在 miui.util.ReflectionUtils.findMethodBestMatch(ReflectionUtils.java:375) 在 miui.util.ReflectionUtils.callMethod(ReflectionUtils.java:800) 在 miui.util.ReflectionUtils.tryCallMethod(ReflectionUtils.java:818) 在 android.os.BaseLooper.enableMonitor(BaseLooper.java:47) 在 android.os.Looper.prepareMainLooper(Looper.java:112) 在 android.app.ActivityThread.main(ActivityThread.java:6221) 在 java.lang.reflect.Method.invoke（本机方法）在 com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:904) 在 com.android.internal.os.ZygoteInit.main(ZygoteInit.java:794)

Answer 1

你的"listData"ArrayList是一个String类型的数组列表。所以你只能在其中添加字符串。你需要创建一个 class like

class Model {
    String name;
    String desc;
    int price;
}

然后创建模型的数组列表。

ArrayList< Model> listData = new ArrayList<>();

然后将该模型 ArrayList 传递给适配器，并在需要时也可以获取。

我正在使用列表视图 Activity 将数据发送到编辑数据 Activity，这里有什么问题？

I'm using List View Activity to send data to Edit Data Activity, what's the problem here?

java

android

android-listview