Question

我有一个稍微复杂的问题。我有一个listview（每行包含3个textviews），由SimpleCursorAdapter填充，listview上方是Seekbar。意味着要发生的是当移动搜索栏时，中间文本视图的值应该改变（中间textview * seekbar.getProgress（）的值）。

为了做到这一点，我创建了一个Cursor，它从数据库中返回所需的信息，这些值存储在变量中并乘以seekbar进度，最后添加到数组中

我遇到的问题是使用数组中的新值填充listview。当我滑动搜索条时，listview中的原始值就会消失，并且没有新值输入到列表中。

我的问题是，如何将所有3个textviews与数组中的新值一起填充到listview中？

代码

public void onProgressChanged(SeekBar seekBar, int progresValue, boolean fromUser) {
    progress = progresValue;
    textView.setText("Serving Size:" + progress);
    int newServings = seekBar.getProgress();

    //read adapter into array multiplying measurement as you go and display new adapter
    final Cursor ingredient2 = adapter.getRecipesIngredients(recipeCode);
    ingredient2.moveToFirst();
    ArrayList<String> newIngredients = new ArrayList<String>();
    while(ingredient2.moveToNext()) {
        String ingredientName = ingredient2.getString(ingredient2.getColumnIndex("ingredient_name"));
        int newMeasurement = ingredient2.getInt(ingredient2.getColumnIndex("measurement"));
        newMeasurement = newMeasurement * progress;
        String newMes = Integer.toString(newMeasurement);
        String ingredientUnit = ingredient2.getString(ingredient2.getColumnIndex("unit"));
        newIngredients.add(ingredientName);
        newIngredients.add(newMes);
        newIngredients.add(ingredientUnit);
    }
    ingredient2.close();

    ArrayAdapter newList = new ArrayAdapter<String>(getApplicationContext(), R.layout.row4,newIngredients);
    ListView ingredientsRecquired2 = (ListView) findViewById(R.id.ingredientsRequired);
    ingredientsRecquired2.setAdapter(newList);
 }

列表视图行布局（第5行）

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent" android:layout_height="match_parent">

    <TextView
        android:id="@+id/ingredientName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="5dp"
        android:textColor="#000000"/>

    <TextView
        android:id="@+id/ingredientMeasurement"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_toRightOf="@+id/ingredientName"
        android:padding="5dp"
        android:textColor="#000000"/>

    <TextView
        android:id="@+id/ingredientUnit"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_toRightOf="@+id/ingredientMeasurement"
        android:padding="5dp"
        android:textColor="#000000"/>

</RelativeLayout>

Answer 1

我认为有很多不同的方法可以实现这一目标。如果我的问题正确，你想要这样的东西吗？

https://gist.github.com/bradwilson/8423477

以下是我的版本如何实现：为列表视图创建自定义数组适配器，并为自定义Ingredient对象创建每个对象的db信息。从您的数据库获取数据，并在自定义适配器getView方法代码中更改每个SeekBar进度的更新视图。

演示代码：

<强> MainActivity.java

import android.content.Context;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.SeekBar;
import android.widget.TextView;

import java.util.ArrayList;


public class MainActivity extends FragmentActivity implements SeekBar.OnSeekBarChangeListener {
    private SeekBar seekBar;
    private ListView listView;
    private MyCustomAdapter listViewAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        seekBar = (SeekBar) findViewById(R.id.seekBar);

        listView = (ListView) findViewById(R.id.listView);
        seekBar.setOnSeekBarChangeListener(this);
        listViewAdapter =  new MyCustomAdapter(getApplicationContext());
        listView.setAdapter(listViewAdapter);

        updateListDataFromDB();
    }

    private void updateListDataFromDB(){
        ArrayList<Ingredient> data = listViewAdapter.getDataArray();
        data.clear();

        //test data instead of data from db
        data.add(new Ingredient("One", 123, "kg"));
        data.add(new Ingredient("Two", 15, "kg"));
        data.add(new Ingredient("Three", 10, "kg"));

        /*
        final Cursor ingredient2 =  adapter.getRecipesIngredients(recipeCode);

        ingredient2.moveToFirst();

        while(ingredient2.moveToNext()) {
            String ingredientName = ingredient2.getString(ingredient2.getColumnIndex("ingredient_name"));
            int newMeasurement = ingredient2.getInt(ingredient2.getColumnIndex("measurement"));
            String ingredientUnit = ingredient2.getString(ingredient2.getColumnIndex("unit"));
            Ingredient newIngredient = new Ingredient(ingredientName, newMeasurement, ingredientUnit);
            data.add(newIngredient);
        }

        ingredient2.close();
        */

        listViewAdapter.notifyDataSetChanged();
    }

    public void onProgressChanged(SeekBar seekBar, int progressValue, boolean fromUser) {
        listViewAdapter.notifyDataSetChanged();
    }

    @Override
    public void onStartTrackingTouch(SeekBar seekBar) {

    }

    @Override
    public void onStopTrackingTouch(SeekBar seekBar) {

    }

    public class MyCustomAdapter extends BaseAdapter{
        private ArrayList<Ingredient> data = new ArrayList<>();
        private Context context;

        public MyCustomAdapter(Context context){
            this.context = context;
        }

        public ArrayList<Ingredient> getDataArray(){
            return data;
        }

        @Override
        public int getCount() {
            return data.size();
        }

        @Override
        public Ingredient getItem(int position) {
            return data.get(position);
        }

        @Override
        public long getItemId(int position) {
            return position;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            if(convertView == null){
                convertView = LayoutInflater.from(context).inflate(R.layout.row, null);
            }

            TextView nameView = (TextView) convertView.findViewById(R.id.ingredientName);
            TextView measurementView = (TextView) convertView.findViewById(R.id.ingredientMeasurement);
            TextView unitView = (TextView) convertView.findViewById(R.id.ingredientUnit);
            Ingredient ingredient = getItem(position);

            nameView.setText(ingredient.name);
            int currMeasurement = ingredient.measurement * (seekBar.getProgress() + 1); // +1 because seekBar default value is 0;
            measurementView.setText(String.valueOf(currMeasurement));
            unitView.setText(ingredient.unit);

            return convertView;
        }
    }

    private class Ingredient {
        public String name;
        public int measurement;
        public String unit;

        public Ingredient(String name, int measurement, String unit) {
            this.name = name;
            this.measurement = measurement;
            this.unit = unit;
        }
    }
}

<强> activity_main.xml中

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin">

    <SeekBar
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/seekBar"
        android:padding="20dp"/>

    <ListView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/listView"
        android:layout_weight="1" />
</LinearLayout>

row.xml - 与Listview行布局（第5行）相同

Answer 2

你需要调用＆＃34; notifyDataSetChanged＆＃34;适配器上的方法来进行更改。

使用多个文本视图填充列表

2 个答案: