将 Spinner 与 SimpleCursorAdapter 结合使用
我有一个活动，其中有一个 Spinner 小部件来显示类别。最初，我使用 ArrayAdapter 来填充微调器，如以下代码所示。
private static final String[] arrayCategories = {
"Business",
"Personal"
};
mCatSpinner = (Spinner) findViewById(R.id.thecategory);
ArrayAdapter<String> catAdapter = new ArrayAdapter<String>(this, R.layout.track_category_item, arrayCategories);
catAdapter.setDropDownViewResource(R.layout.track_category_dropdown_item);
mCatSpinner.setAdapter(catAdapter);
这工作正常，如果未进行选择，微调器默认显示第一个数组项。当实际选择某个项目时，它确实显示所选项目
，但现在我想使用 SimpleCursorAdapter 从数据库中提取列表内容。所以我将其更改为
SimpleCursorAdapter scaCategories = new SimpleCursorAdapter(this, R.layout.track_category_item,cCategories,new String[] {DBAdapter.KEY_CATEGORIES_NAME},new int[]{R.id.text1});
scaCategories.setDropDownViewResource(R.layout.track_category_dropdown_item);
mCatSpinner = (Spinner) findViewById(R.id.thecategory);
mCatSpinner.setAdapter(scaCategories);
“填充下拉列表”，但它不显示微调器中的第一项。即使选择，也不会显示所选项目。
我尝试使用 setSlection 到第一个项目，
if(mCatSpinner.isSelected() != true) {
mCatSpinner.setSelection(0);
}
但它不起作用
出了什么问题？
I have an activity which has a Spinner widget to display categories. Initially I was using an ArrayAdapter to populate the the spinner as in the following code
private static final String[] arrayCategories = {
"Business",
"Personal"
};
mCatSpinner = (Spinner) findViewById(R.id.thecategory);
ArrayAdapter<String> catAdapter = new ArrayAdapter<String>(this, R.layout.track_category_item, arrayCategories);
catAdapter.setDropDownViewResource(R.layout.track_category_dropdown_item);
mCatSpinner.setAdapter(catAdapter);
This works fine, and the spinner displays the first array item by default if no selection is made. It does show the selected item when an item is actually selected
But now I want to use a SimpleCursorAdapter to pull the list contents from a db. So I changed it to
SimpleCursorAdapter scaCategories = new SimpleCursorAdapter(this, R.layout.track_category_item,cCategories,new String[] {DBAdapter.KEY_CATEGORIES_NAME},new int[]{R.id.text1});
scaCategories.setDropDownViewResource(R.layout.track_category_dropdown_item);
mCatSpinner = (Spinner) findViewById(R.id.thecategory);
mCatSpinner.setAdapter(scaCategories);
This populates the dropdown, but it does not display the first item in the spinner. Even if selected, it does not show the selected item.
I tried to setSlection to the first item using
if(mCatSpinner.isSelected() != true) {
mCatSpinner.setSelection(0);
}
but it didn't work
What is wrong?
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好的，如果我在布局 xml 中指定小部件 id 将会有所帮助。 <:(
Ok, it would help if I specified the widget id in the layout xml. <:(