Question

我是Android开发的新手，目前使用listview。我的所有项目都正确显示，但现在我想根据内容从我的drawable文件夹中添加一个图像。

ListView lv=(ListView)findViewById(R.id.listView_event);
    ListAdapter adapter = new SimpleAdapter(
            this, eventList,
            R.layout.list_item_event, new String[] { "name", "date" }, 
new int[]  {R.id.name, R.id.date});
lv.setAdapter( adapter );

我的eventList包含更多字段，例如＆＃34; type＆＃34;它只有三种不同的价值观。现在万一它包含type1我希望它从可绘制文件夹（R.drawable）中取出png图像type1。有没有人这么善良，请给我一个提示？

Answer 1

试用本教程：

http://webdeveloperpadawan.blogspot.co.uk/2014/09/android-listview-with-differing-rows.html

简而言之，在getView（）内部，你需要检查类型并根据它设置图像。

Answer 2

只需制作一个可绘制图像的整数数组，如{R.drawable.image1，R.drawable.image2}; 并根据数据来自array.you必须映射这样的整数值。

Answer 3

基本上，为了将图片包含到列表视图中，您需要有一个自定义适配器。

为此，创建一个扩展Adapter的类（或者在此示例中为ArrayAdapter）：

public class ParticipantAdapter extends ArrayAdapter<Participant> {

private final Context context;
private final List<Participant> values;
private final String urlToProfilePics;

public ParticipantAdapter(Context context, int resource,
        List<Participant> objects) {
    super(context, resource, objects);
    this.context = context;
    this.values = objects;
}

public ParticipantAdapter(Context context, int resource) {
    super(context, resource);
    this.context = context;
    this.values = new ArrayList<Participant>();
    // Obtain the external cache directory
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    LayoutInflater inflater = (LayoutInflater) context
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    View participantView;
    participantView = inflater.inflate(R.layout.participant_item, parent, false);

    TextView textView = (TextView) participantView.findViewById(R.id.participantName);
    textView.setText(getItem(position).getName());
    ImageView imageView = (ImageView) participantView.findViewById(R.id.participantImage);

    //you can add varibles to the class that represents your items and use it like so to determine the image displayed
    int someContext = getItem(position).someContextOfTheCurrentItem;
    switch(someContext) {
        case DOG:
            imageView.setImageResource(R.drawable.dog);
            break;
        case CAT:
            imageView.setImageResource(R.drawable.cat);
            break;
    }

    //here are some other things you can do on the image based on the context of your item
    if(!getItem(position).someBoolean) {
        imageView.setImageAlpha(80);
        int lightGrey = context.getResources().getColor(R.color.light_grey);
        textView.setTextColor(lightGrey);
    } else {
        int black = context.getResources().getColor(R.color.black);
        textView.setTextColor(black);
    }

    return participantView;
}

public List<Participant> getValues() {
    return this.values;
}

注意getView方法。它的作用是获取包含图像的布局的XML文件，并根据每个项目的上下文对其进行操作。

在这个例子中，我有一个名为Participant的单独类，它包含一个整数和一个布尔值，我在getView方法中进行测试，并根据它们的值我可以更改返回的View将代表什么。

这是我在这个例子中使用的布局的xml文件（它只是一张图片，右边是文本视图）：

<?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" >

<ImageView
    android:id="@+id/participantImage"
    android:layout_width="52dp"
    android:layout_height="52dp"
    android:contentDescription="@string/contentDescriptionParticipantImage"
    android:maxWidth="@dimen/tom_max_width_participant_image"
    android:src="@drawable/profile_placeholder" />

<TextView
    android:id="@+id/participantName"
    android:layout_width="match_parent"
    android:layout_height="52dp"
    android:padding="@dimen/tom_small_text_padding"
    android:text="TextView"
    android:textColorHint="@color/black"
    android:textSize="@dimen/tom_participant_item_text_size" />

Answer 4

感谢大家的回答。最后，我可以按照新课程

的建议进行管理

public class EventAdapter extends SimpleAdapter {

private final Activity context;
private final String[] string_event;
private final int[] int_event;
private final ArrayList<HashMap<String, String>> items;

public EventAdapter(Activity context, ArrayList<HashMap<String, String>> items,
                    String[] string_event, int[] int_event) {
    super(context, items, R.layout.list_item_event, string_event, int_event);

    this.context = context;
    this.string_event = string_event;
    this.int_event = int_event;
    this.items = items;
}

@Override
public View getView(int position, View view, ViewGroup parent) {
    LayoutInflater inflater = context.getLayoutInflater();
    View rowView= inflater.inflate(R.layout.list_item_event, null, true);

    System.out.println("Items position: " + items.get(position));
    EventClass currentEvent = new EventClass(items.get(position).get("name").toString(), items.get(position).get("location"), items.get(position).get("date")
                , items.get(position).get("type"), items.get(position).get("theme"),items.get(position).get("link"));

    TextView txtName = (TextView) rowView.findViewById(int_event[0]);
    TextView txtDate = (TextView) rowView.findViewById(int_event[1]);
    ImageView imageView = (ImageView) rowView.findViewById(R.id.imageView_type);

    txtName.setText(currentEvent.getEvent_name());
    txtDate.setText(android.text.format.DateFormat.format("dd MMMM yyyy",currentEvent.getDate()));

    if(currentEvent.getType().equals("triathlon")) {
        imageView.setImageResource(R.drawable.triathlon_70);
    }
    if(currentEvent.getType().equals("run")) {
        imageView.setImageResource(R.drawable.ic_run_70);
    }
    if(currentEvent.getType().equals("cycling")) {
        imageView.setImageResource(R.drawable.ic_cycle_70);
    }

    return rowView;
}

}

我真的假设它首先会更容易:) 再次感谢

Listview与图像取决于上下文

4 个答案: