getView & 的区别SpinnerAdapter 中的 getDropDownView [英] Difference between getView & getDropDownView in SpinnerAdapter

问题描述

当您实现 SpinnerAdapter 时，您会得到 getDropDownView，它与需要扩展BaseAdapter时的getView有什么区别.

When you implement SpinnerAdapter you get getDropDownView, how does it differ from getView which you have when you need to extend BaseAdapter.

推荐答案

如果我们看下面的代码，我们在 getView 和 getDropDownView 中有 name 和 value 数组.

If we look at the following code, we have name and value array in getView and getDropDownView.

private void initView() {
    SpinnerDropDownAdapter sddadapter = new SpinnerDropDownAdapter(this);
    ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
            android.R.layout.simple_spinner_item, sddadapter.name);

    Spinner getViewSP = (Spinner) findViewById(R.id.getview_sp);
    getViewSP.setAdapter(adapter);

    Spinner getViewWDropDownSP = (Spinner) findViewById(R.id.getview_w_drop_down_sp);
    getViewWDropDownSP.setAdapter(sddadapter);
}

static class SpinnerDropDownAdapter extends BaseAdapter implements
        SpinnerAdapter {
    Context context;

    SpinnerDropDownAdapter(Context ctx) {
        context = ctx;
    }

    String[] name = { " One", " Two", " Three", " Four", " Five", " Six",
            " Seven", " Eight" };
    String[] value = { " 1", " 2", " 3", " 4", " 5", " 6", " 7", " 8" };

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

    @Override
    public String getItem(int pos) {
        // TODO Auto-generated method stub
        return name[pos];
    }

    @Override
    public long getItemId(int arg0) {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        TextView text = new TextView(context);
        text.setTextColor(Color.BLACK);
        text.setText(name[position]);
        return text;
    }

    @Override
    public View getDropDownView(int position, View convertView,
            ViewGroup parent) {
        TextView text = new TextView(context);
        text.setTextColor(Color.BLACK);
        text.setText(value[position]);
        return text;
    }
}

如果没有实现 getDropDownView 方法，下拉弹出窗口将从 getView 获取视图.因此，它只会显示名称.

If getDropDownView method is not implemented, the drop down pop up will get the view from getView. Thus, it will only show name.

当同时实现 getView 和 getDropDownView 时，前者获取 name，后者获取 value，静止的 spinner 将从中获取 namegetview 和下拉弹出窗口将获得 value.

When both getView and getDropDownView is implemented, the former getting name and the latter getting value, the spinner at rest will get name from getview and the drop down pop up will get value.

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