不同的列表视图项目的不同选择颜色

时间:2014-06-18 12:07:52

标签: java android listview user-interface

我有以下要求:

  • 不同列表视图项目的不同颜色
  • 颜色在代码中动态指定
  • 只应在按下/选择列表视图项目时显示颜色
  • 列表视图项的颜色不应永久更改

无论出于何种原因,似乎没有像我想象的那样直截了当。唯一能够朝着正确方向前进的解决方案是:https://stackoverflow.com/a/16978159/658718

需要注意的是,这不会更改选择的颜色,但会永久更改背景颜色,如果向下滚动,它已经更改了列表视图项的背景颜色。

我该如何处理?

4 个答案:

答案 0 :(得分:2)

我会说state-aware drawables。为您想要单个ListView背景的每种颜色创建一个状态感知的可绘制XML文件。以下是一个名为background_black.xml和background_green.xml的状态感知Drawable的示例。它们使您的默认背景颜色为白色,而按下/选择时会暂时将其更改为黑色或绿色。这两个文件都放在Drawable文件夹中。

<强> background_black.xml     

<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_window_focused="false" android:drawable="@android:color/white" />
    <item android:state_pressed="true" android:color="@android:color/black" />
    <item android:state_selected="true" android:color="@android:color/black" />
</selector>

<强> background_green.xml     

<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_window_focused="false" android:drawable="@android:color/white" />
    <item android:state_pressed="true" android:color="@android:color/green" />
    <item android:state_selected="true" android:color="@android:color/green" />
</selector>

在ListView项目xml文件中,为根布局或任何提供可见背景颜色的元素指定ID。对于此示例,Ill假设它是您的根布局。然后在您的Adapter的getView()中,抓取您已分配id的元素,并使用您想要的背景颜色设置您创建的一个drawable。像这样:

@Override
public View getView(int position, View convertView, ViewGroup parent){
     //inflate your convertView, etc...
     ...
     ViewGroup baseLayout = (ViewGroup)convertView.findViewById(R.id.<your base layout id>);

     //these conditions need to reflect how you decide which list item gets which color
     if(position % 2 == 0){
         baseLayout.setBackground(R.drawable.background_black);
     } else {
         baseLayout.setBackground(R.drawable.background_green);
     //do whatever else you need
     ...
     return convertView;
}

注意:setBackground()是一个新函数,如果编码旧版Android,则使用setBackgroundDrawable()

答案 1 :(得分:2)

这里的难点在于按下/选中的颜色是动态的。您不能使用静态xml color-state-list。但您可以按代码创建ColorStateList。这是如何做到的。

您只需要实现ListAdapter:

private class MyListAdapter implements ListAdapter{

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        if(convertView!=null){
             CheckedTextView textView = (CheckedTextView)convertView;
             textView.setText("the text for item "+position);
             textView.setTextColor(makeColorStateListForItem(position));
             return textView;
        }else{
             CheckedTextView textView = new CheckedTextView(parent.getContext());
             textView.setText("the text for item "+position);
             textView.setTextColor(makeColorStateListForItem(position));
             return textView;
        }
    }

    private ColorStateList makeColorStateListForItem(int position){
        int pressedColor = pressedColorForItem(position);
        int checkedColor = checkedColorForItem(position);
        int defaultColor = defaultColorForItem(position);
        ColorStateList colorStateList = new ColorStateList(
                new int[][]{
                        new int[]{android.R.attr.state_pressed},
                        new int[]{android.R.attr.state_checked},
                        new int[]{0},
                },
                new int[]{
                        pressedColor, //use when state is pressed
                        checkedColor, //use when state is checked, but not pressed
                        defaultColor}); //used when state is not pressed, nor checked 
    }

    private int pressedColorForItem(int position){
        //write your business logic to determine color here
        return ...;
    }

    private int checkedColorForItem(int position){
        //write your business logic to determine color here
        return ...;
    }

    private int defaultColorForItem(int position){
        return Color.WHITE;
    }

    //all other adapter methods
    //...

请注意使用android.R.attr.state_checked而不是更直观的android.R.attr.state_selected,因为state_selected不是用触摸屏非常精确地定义的(即state_selected可以在模拟器上给出预期的行为,但在真实设备上它可能会失败)

另一方面,state_checked + CheckedTextView将在模拟器和真实设备上正常工作。

在clickListener中初始化listView和List.setChoiceMode(...);时,只需调用ListView.setItemChecked

final ListView listView = ...
listView.setAdapter(new MyListAdapter());
listView.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
        listView.setItemChecked(position,true);
    }
});

编辑:更改项目背景:只需创建StateListDrawable而不是简单的ColorStateList:

private Drawable makeBackgroungForItem(int position){
    int pressedColor = pressedBackgroundColorForItem(position);
    int checkedColor = checkedBackgroundColorForItem(position);
    int defaultColor = defaultBackgroundColorForItem(position);
    StateListDrawable stateListDrawable = new StateListDrawable();
    stateListDrawable.addState(new int[]{android.R.attr.state_list_pressed}, new ColorDrawable(pressedColor));
    stateListDrawable.addState(new int[]{android.R.attr.state_list_checked}, new ColorDrawable(checkedColor));
    stateListDrawable.addState(new int[]{0, new ColorDrawable(defaultColor));
    return stateListDrawable;
}

getView(...)

textView.setBackground(makeBackgroungForItem(position));

答案 2 :(得分:1)

我建议采用以下方法:

  • 您需要创建支持多个不同商品的ListView Adapter
  • 每个不同的Item类代表不同的颜色,并且可以自己实现如何处理按下或选择的状态
  • 由于每个ListItem都有自己的.xml布局文件,因此您可以指定所需的选择器

你需要什么:

  • 基类 ListItem ListView中的每个项目都来自
  • 此类提供抽象方法来获取表示项目的View及其类型
  • 如果需要,ListItem类可以有一个Integer字段mColor,用于保存项目所代表的颜色
  • 如果需要,ListItem类可以有一种方法来设置具有特定颜色的选择器

示例:

public abstract class ListItem {

    public static final int TYPE_WHATEVER_1                     = 0;
    public static final int TYPE_WHATEVER_2                     = 1;
    // and so on...

    /** the total number of list-item-types */
    public static final int TYPE_COUNT              = typecounthere;

    // if required for your implementation:
    protected int mColor;

    public abstract int getViewType();
    public abstract View getView(LayoutInflater inflater, View convertView);

    /** creates and sets the selector with your specified color */
    public void setupSelectorColor() {

        StateListDrawable states = new StateListDrawable();

        ColorDrawable cdPressed = new ColorDrawable(mColor);
        ColorDrawable cdSelected = new ColorDrawable(mColor);
        ColorDrawable cdDefault = new ColorDrawable(Color.TRANSPARENT);

        states.addState(new int[] {
                android.R.attr.state_pressed
        },
                cdPressed);
        states.addState(new int[] { 
                android.R.attr.state_selected
        },
                cdSelected);
        states.addState(new int[] {},
                cdDefault);

        setBackgroundDrawable(states);
    }
}
  • 对于每种颜色,请创建ListItem
  • 的子类
  • getView(...)方法内,夸大您想要的布局
  • 不要忘记在getViewType()方法
  • 中返回正确的类型
  • 在这里用你的颜色做任何你想做的事
  • 使用您的颜色设置选择器

示例:

public class ItemTypeOne extends ListItem {

    public ItemTypeOne(int color) {
        mColor = color;
    }

    @Override
    public int getViewType() {
            // return the type
        return TYPE_WHATEVER_1;
    }

    @Override
    public View getView(LayoutInflater inflater, View convertView) {

        if(convertView == null) {
            // inflate the layout 
            convertView = inflater.inflate(R.layout.item_type_one, null);
        }    

        // setup the selector
        setupSelectorColor();

        // do other stuff

        return convertView;
    }
}
  • 支持不同项类型的适配器

示例:

public class ListItemAdapter extends ArrayAdapter<ListItem> {

    public ListItemAdapter(Context context, List<ListItem> objects) {
        super(context, 0, objects);
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        return getItem(position).getView(LayoutInflater.from(getContext()), convertView);
    }

    @Override
    public int getItemViewType(int position) {
        return getItem(position).getViewType();
    }

    @Override
    public int getViewTypeCount() {
        return ListItem.TYPE_COUNT;
    }
}

全部放在一起:

ArrayList<ListItem> list = new ArrayList<ListItem>();
// fill the list
list.add(new ItemTypeOne(somecolor));
list.add(new ItemTypeTwo(somecolor));
list.add(new ItemTypeOne(somecolor));
list.add(new ItemTypeWhatever(somecolor));

ListView lv = (ListView) v.findViewById(R.id.listView1);

ListItemAdapter a = new ListItemAdapter(Context, list);         
lv.setAdapter(a);

关于CustomViews选择器及其行为,我建议您阅读此问题(并回答): How to implement a CustomView with custom selector states?

答案 3 :(得分:-1)

我说不要过分复杂。它可以很简单,因为创建一个包含可能颜色的int数组,并使用Random类将它们设置为每个项目。

// This goes inside hosting fragment or activity
listview.setOnItemClickListner( new OnItemClickListener() {
      @Override
      public void onItemClick(AdapterView parent, View view, int position, long id) {
           if(view.isSelected()){
               view.setSelected(false);
               // also maybe change bg color back to normal?
           }

           else {
                // This one for always a different color
                view.setBackgroundColor(adapter.getColor());

                // This is for foreground color change instead of background
                FrameLayout frameLayout = (FrameLayout) view.findViewById(R.id.my_frame_layout);

                final Drawable drawable = new ColorDrawable( /*  your getColor() function  */ );
                frameLayout.setForeground(drawable);

                // This one for alwyas the same color for the row at position given by {@param position}
                view.setBackgroundColor(adapter.getColor(position));
                view.setSelected(true);
           }
      }
});



// All this goes inside your custom listview Adapter
int[] colors = {
      R.colors.red,
      R.colors.blue,
      ...
}

Random random = new Random();

// If each time the selection will bring a different color, use this implementation
public int getColor() {
    return colors[random.nextInt(colors.length)]; 
}

// If each row should have different color, but always the same color for a row then use this one instead
SparseIntArray spa = new SparseIntArray();
public int getColor(int position) {
     if(spa.get(position) == 0) {
         // the color hasnt been created for that row yet
         spa.put(position, colors[random.nextInt(colors.length)];
     }

     return spa.get(position);     
}

**编辑:**现在,如果您想要的是前景选择,那么您的行应该有一个FrameLayout容器,您应该更改它&#39; android:前景&# 39;属性:

final Drawable drawable = new ColorDrawable( /*  your getColor() function  */ );
frameLayout.setForeground(drawable);