微调器项目的单独背景颜色

Question

我想为旋转器个体的每个项目的背景着色。 这些项目是用这个代码设置的：

Spinner spinner = (Spinner) findViewById(R.id.spinner);
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this,
            R.array.duesentypen, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(adapter);

十六进制值存储在一个数组中。而索引计数是指项目计数。例如：

String[] hex = {"#886da8", "#ffc3cf","#ef9b00", "#2bb430", "#f7dc01", "#bc65a2", "#487ebf","#e00124","#b36634","#949494", "#ffffff","#000000","#4bbbd0", "#8b6d9f", "#8ccff4"};
//color for the first spinner item: hex[0]
//color for the second spinner item: hex[1]

我怎样才能以最好的方式做到这一点？

Answer 1

您需要创建一个自定义的Spinner 适配器并覆盖getView() 来设置每个项目的颜色和文本。

在这里，我使用模运算符 (%) 将颜色环绕在颜色数组周围，以避免在项目大于可用颜色时出现IndexOutOfBoundsExecption。

自定义适配器

public class ColorAdapter extends BaseAdapter {

    private ArrayList<Integer> mColors;
    private String[] mItems;

    ColorAdapter2(String[] items) {
        mItems = items;
        String[] hex = {"#886da8", "#ffc3cf", "#ef9b00", "#2bb430", "#f7dc01", "#bc65a2", "#487ebf", "#e00124", "#b36634", "#949494", "#ffffff", "#000000", "#4bbbd0", "#8b6d9f", "#8ccff4"};

        mColors = new ArrayList<>();
        for (String color : hex) {
            mColors.add(Color.parseColor(color));
        }

    }

    @Override
    public int getCount() {
        return mItems.length;
    }

    @Override
    public Object getItem(int args) {
        return mColors.get(args);
    }

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        ViewHolder holder;

        if (convertView == null) {
            LayoutInflater inflater = LayoutInflater.from(parent.getContext());
            convertView = inflater.inflate(android.R.layout.simple_spinner_dropdown_item, null);
            holder = new ViewHolder();
            holder.textView = convertView.findViewById(android.R.id.text1);
            convertView.setTag(holder);

        } else {
            holder = (ViewHolder) convertView.getTag();
        }

        holder.textView.setBackgroundColor(mColors.get(position % mColors.size()));
        holder.textView.setText( mItems[position]);
        return convertView;
    }

    /* Return spinner text of the item at particular position*/
    public String getItemAtPosition(int position) {
        if (position > -1 && position < mItems.length)
            return mItems[position];
        else
            return null;
    }

    static class ViewHolder {
        TextView textView;
    }

}

用法

Spinner spinner = findViewById(R.id.spinner);
spinner.setAdapter(new ColorAdapter(getResources().getStringArray(R.array.myItems)));

strings.xml

<resources>
    <string name="app_name">Color Activity</string>
    <string-array name="myItems">
        <item>item1</item>
        <item>item2</item>
        <item>item3</item>
        <item>item4</item>
        <item>item5</item>
    </string-array>
</resources>

结果

编辑

如何获取所选项目的文本？ spinner.getItemAtPosition(spinner.getSelectedItemPosition()).toString() 不再工作了。返回值是一个很大的数字。

现在我们创建了一个自定义适配器，那么您必须自定义任何相关数据，并且您不能依赖默认 Spinner 适配器的 API；所以我在上面的自定义适配器中添加了一个getItemAtPosition() 方法，该方法获取一个位置，并返回该项目的文本。

用法

String item = ((ColorAdapter)spinner.getAdapter()).getItemAtPosition(position));

而且你可以在选择一个项目时得到它：

spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {

        Log.d(TAG, "onItemSelected: " + 
              ((ColorAdapter)spinner.getAdapter()).getItemAtPosition(position));

    @Override
    public void onNothingSelected(AdapterView<?> parent) {

    }
});

Answer 2

尝试根据位置改变颜色。

final List<String> plantsList = new ArrayList<>(Arrays.asList(plants));

        ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this,
            R.array.duesentypen, android.R.layout.simple_spinner_item){
            @Override
            public View getDropDownView(int position, View convertView,
                                        ViewGroup parent) {
                View view = super.getDropDownView(position, convertView, parent);
                TextView tv = (TextView) view;

        switch(position) {
             case 0:
                tv.setTextColor(Color.parseColor("#FF7C7967"));
             case 1:
                tv.setTextColor(Color.parseColor("#FF7C7967"));
                   }

                return view;
            }
        };

        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner.setAdapter(adapter);