如何从微调单选变为多选

Question

我正在尝试将微调器从单选更改为多选，并且尝试下载其他库，但似乎无法正常工作。有人可以帮我吗？ ：'（

当前我的代码是：

sp=(Spinner)findViewById(R.id.sp);

String[] dia = new String[]{
    "None",
    "A",
    "B",
    "C",
    "D",
};
sp.setAdapter(new ArrayAdapter<>(context, android.R.layout.simple_spinner_dropdown_item, dia));
sp.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
    @Override
    public void onItemSelected(AdapterView<?> adapterView, View view, int i, long Id) {
        if (i == 0) { 
            return;
        }
        i--;
    }
    @Override
    public void onNothingSelected(AdapterView<?> adapterView) { }
});

Answer 1

这里是用于多项选择的自定义微调器，非常易于集成。试试吧

package com.android.spinnerexample;

public class MultiSpinner extends Spinner implements
        OnMultiChoiceClickListener, OnCancelListener {

    private List<String> items;
    private boolean[] selected;
    private String defaultText;
    private MultiSpinnerListener listener;

    public MultiSpinner(Context context) {
        super(context);
    }

    public MultiSpinner(Context arg0, AttributeSet arg1) {
        super(arg0, arg1);
    }

    public MultiSpinner(Context arg0, AttributeSet arg1, int arg2) {
        super(arg0, arg1, arg2);
    }

    @Override
    public void onClick(DialogInterface dialog, int which, boolean isChecked) {
        if (isChecked)
            selected[which] = true;
        else
            selected[which] = false;
    }

    @Override
    public void onCancel(DialogInterface dialog) {
        // refresh text on spinner
        StringBuffer spinnerBuffer = new StringBuffer();
        boolean someUnselected = false;
        for (int i = 0; i < items.size(); i++) {
            if (selected[i] == true) {
                spinnerBuffer.append(items.get(i));
                spinnerBuffer.append(", ");
            } else {
                someUnselected = true;
            }
        }
        String spinnerText;
        if (someUnselected) {
            spinnerText = spinnerBuffer.toString();
            if (spinnerText.length() > 2)
                spinnerText = spinnerText.substring(0, spinnerText.length() - 2);
        } else {
            spinnerText = defaultText;
        }
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(getContext(),
                android.R.layout.simple_spinner_item,
                new String[] { spinnerText });
        setAdapter(adapter);
        listener.onItemsSelected(selected);
    }

    @Override
    public boolean performClick() {
        AlertDialog.Builder builder = new AlertDialog.Builder(getContext());
        builder.setMultiChoiceItems(
                items.toArray(new CharSequence[items.size()]), selected, this);
        builder.setPositiveButton(android.R.string.ok,
                new DialogInterface.OnClickListener() {

                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.cancel();
                    }
                });
        builder.setOnCancelListener(this);
        builder.show();
        return true;
    }

    public void setItems(List<String> items, String allText,
            MultiSpinnerListener listener) {
        this.items = items;
        this.defaultText = allText;
        this.listener = listener;

        // all selected by default
        selected = new boolean[items.size()];
        for (int i = 0; i < selected.length; i++)
            selected[i] = true;

        // all text on the spinner
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(getContext(),
                android.R.layout.simple_spinner_item, new String[] { allText });
        setAdapter(adapter);
    }

    public interface MultiSpinnerListener {
        public void onItemsSelected(boolean[] selected);
    }
}

您可以像这样在XML中使用它：

<com.android.spinnerexample.MultiSpinner android:id="@+id/multi_spinner" />

然后您像这样将数据传递给Java：

MultiSpinner multiSpinner = (MultiSpinner) findViewById(R.id.multi_spinner);
multiSpinner.setItems(items, getString(R.string.for_all), this);

此外，您还需要实现侦听器，该侦听器将返回相同长度的数组，使用true或false来显示selected为unselected。

public void onItemsSelected(boolean[] selected);