我想知道是否有人可以帮助我编写代码。我有一个微调器，它在一个数组中包含六个项目，第三个项目设置为默认值。当用户选择一个项目时，我希望用户的选择移至微调器的顶部位置。为了澄清，如果我有项目A，B，C，D，E和F：
默认：
C
--
A
B
D
E
F
如果用户选择D：
D
--
A
B
C
E
F
如“图表”所示，我还试图弄清楚如何仅在最上面的选择上放置分隔线。
这是我到目前为止的代码。我刚刚开始学习Android，所以我对所有事情都比较怀疑，但是对您有所帮助，谢谢！
-更新的代码-
public class Test extends AppCompatActivity implements OnItemSelectedListener {
List<String> list;
String [] objects = {"A","B","C","D","E","F"};
ArrayAdapter<String> adapter = new ArrayAdapter<>(this,
android.R.layout.simple_spinner_item, objects);
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_test);
Spinner spinner = (Spinner) findViewById(R.id.spinner);
spinner.setOnItemSelectedListener(this);
list = new ArrayList<>(Arrays.asList(objects));
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(adapter);
spinner.setSelection(2);
adapter.notifyDataSetChanged();
}
public void onItemSelected(AdapterView<?> parent, View view,
int pos, long id) {
list.remove(pos);
objects=list.toArray(new String[0]);
adapter.notifyDataSetChanged();
}
public void onNothingSelected(AdapterView<?> parent) {
}
首先要获得所需的布局，您必须具有一个自定义适配器。
因此，您需要定义一个类，如下所示：
public class MyAdapter extends ArrayAdapter<String>{
Context c;
String [] objects;
public MyAdapter(Context c, String [] objects){
this.c=c;
this.objects=objects;
}
@Override
public View getDropDownView(int position, View cnvtView, ViewGroup prnt) {
return getCustomView(position, cnvtView, prnt);
}
@Override
public View getView(int pos, View cnvtView, ViewGroup prnt) {
return getCustomView(pos, cnvtView, prnt);
}
}
public View getCustomView(int position, View convertView, ViewGroup parent)
{
LayoutInflater inflater = getLayoutInflater();
View mySpinner = inflater.inflate(R.layout.custom_spinner, parent, false);
RelativeLayout layout= (RelativeLayout) mySpinner.findViewById(R.id.layout);
TextView letter= (TextView) mySpinner.findViewById(R.id.letter);
letter.setText(objects[position]);
if(position==0){
layout.setVisibility(true);
}
return mySpinner;
}
至于是custom_spinner.xml的xml：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
>
<TextView
android:id="@+id/letter"
android:height="wrap_content"
android:width="wrap_content"/>
<RelativeLayout
android:id="@+id/layout"
android:visibility="gone"
android:layout_width="match_parent"
android:layout_height="match_parent">
<View
android:id="@+id/line"
android:height="1dp"
android:width="5dp"/>
<View
android:layout_toRightOf="@+id/line"
android:height="1dp"
android:width="5dp"/>
</RelativeLayout>
</RelativeLayout>
然后在您的活动中：
MyAdapter adapter= new MyAdapter(this, spinnerValues);
mySpinner.setAdapter(adapter);
至于从下拉列表中删除所选项目：
您必须在活动中具有以下内容：
List<String> list;
String [] objects;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home_page);
Spinner spinner = (Spinner) findViewById(R.id.spinnerTime);
spinner.setOnItemSelectedListener(this);
objects= {"A","B","C","D","E","F"};
list = new ArrayList<>(Arrays.asList(objects));
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this,
objects, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(adapter);
spinner.setSelection(2);
adapter.notifyDataSetChanged();
}
public void onItemSelected(AdapterView<?> parent, View view,
int pos, long id) {
list = new ArrayList<>(Arrays.asList(R.array.time_period));
list.remove(pos);
objects=list.toArray(new String[0]);
adapter.notifyDataSetChanged();
}
public void onNothingSelected(AdapterView<?> parent) {
}
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