【发布时间】：2018-08-20 02:15:40
【问题描述】：
如何在用户单击单选组中的是或否单选按钮后平滑滚动到列表视图中的下一项。 例如。如果用户对第一个问题回答是或否，它应该平滑滚动到第二个问题。 我找到了下面的代码，它正在使用静态位置值，但我不知道如何在选择单选组（是或否单选按钮）时滚动到下一个索引（下一个问题）。
int index = 0;
int h1 = simpleListView.getHeight();
int h2 = simpleListView.getHeight();
int duration=500;
simpleListView.smoothScrollToPositionFromTop(index+4, h1/2 - h2/2, duration);
1) MainActivity_.class:-----------------
public class MainActivity_ extends AppCompatActivity {
private ListView lv;
private CustomAdapter customAdapter;
private String[] questions;
private Button submit;
private Button clear;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.layout8);
questions = new String[10];
for(int i = 0 ; i<10 ; i++){
questions[i] = "Q " + i;
}
lv = (ListView) findViewById(R.id.lv);
customAdapter = new CustomAdapter(getApplicationContext() , questions);
lv.setAdapter(customAdapter);
submit = (Button) findViewById(R.id.submit);
submit.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
boolean found_unanswered = false;
int index_first_unanswered = 0;
List<Integer> backgroundColor = new ArrayList<Integer>(); // new
if(customAdapter != null){
for(int i = 0 ; i<customAdapter.getSelectedAnswers().size() ; i++){
if(customAdapter.getSelectedAnswers().get(i).equals("3")){
if(!found_unanswered) { // new
found_unanswered = true;
index_first_unanswered = i; // new
}
backgroundColor.add(Color.RED); // new
}else{ // new
backgroundColor.add(Color.WHITE);
}
}
}
if(!found_unanswered) {
Toast.makeText(getApplicationContext(), "All Answered", Toast.LENGTH_LONG).show();
customAdapter.setBackgroundColor(backgroundColor); // new
//Go to other activity
}else{ // new
Toast.makeText(getApplicationContext(), "Found Unanswered", Toast.LENGTH_LONG).show();
if(customAdapter != null && lv != null){
customAdapter.setBackgroundColor(backgroundColor);
lv.smoothScrollToPosition(index_first_unanswered);
}
}
}
});
clear = (Button) findViewById(R.id.clear);
clear.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (customAdapter != null) {
customAdapter.clearSelectedAnswers();
}
}
});
}
}
2) CustomAdapter.class:----------------
public class CustomAdapter extends BaseAdapter {
Context context;
String[] questionsList;
LayoutInflater inflter;
private List<String> selectedAnswers;
private List<Integer> backgroundColor; // new
public CustomAdapter(Context context, String[] questionsList) {
this.context = context;
this.questionsList = questionsList;
selectedAnswers = new ArrayList<String>();
backgroundColor = new ArrayList<Integer>(); // new
for (int i = 0; i < questionsList.length; i++) {
selectedAnswers.add("3");
backgroundColor.add(Color.WHITE); // new
}
inflter = (LayoutInflater.from(context));
}
@Override
public int getCount() {
return questionsList.length;
}
@Override
public Object getItem(int i) {
return questionsList[i];
}
@Override
public long getItemId(int i) {
return i;
}
@Override
public int getViewTypeCount() {
return questionsList.length;
}
@Override
public int getItemViewType(int i) {
return i;
}
@Override
public View getView(final int i, View convertView, ViewGroup viewGroup) {
View view = convertView;
if (convertView == null) {
if (inflter != null) {
view = inflter.inflate(R.layout.list_items, null);
}
}
TextView question = (TextView) view.findViewById(R.id.question);
question.setText(questionsList[i]);
question.setBackgroundColor(backgroundColor.get(i)); // new
// initialize/re-restore UI Radio Button State
final RadioGroup rg = (RadioGroup) view.findViewById(R.id.radio_group);
RadioButton rb_yes = (RadioButton) rg.findViewById(R.id.yes);
RadioButton rb_no = (RadioButton) rg.findViewById(R.id.no);
if(selectedAnswers.get(i).equals("1")){
rg.check(R.id.yes);
rb_yes.setBackgroundColor(Color.GREEN);
rb_no.setBackgroundColor(Color.GRAY);
}else if(selectedAnswers.get(i).equals("2")){
rg.check(R.id.no);
rb_yes.setBackgroundColor(Color.GRAY);
rb_no.setBackgroundColor(Color.BLACK);
}else {
// no answer.
rg.clearCheck(); // new
rb_yes.setBackgroundColor(Color.GRAY);
rb_no.setBackgroundColor(Color.GRAY);
}
rg.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(RadioGroup group, int checkedId) {
RadioButton rb_yes = (RadioButton) group.findViewById(R.id.yes);
RadioButton rb_no = (RadioButton) group.findViewById(R.id.no);
//Toast.makeText(context , (checkedId == R.id.yes)?"yes":"no" , Toast.LENGTH_LONG).show();
switch (checkedId){
case R.id.yes:
rb_yes.setBackgroundColor(Color.GREEN);
rb_no.setBackgroundColor(Color.GRAY);
selectedAnswers.set(i, "1");
break;
case R.id.no:
rb_yes.setBackgroundColor(Color.GRAY);
rb_no.setBackgroundColor(Color.BLACK);
selectedAnswers.set(i, "2");
break;
default: // new
rb_yes.setBackgroundColor(Color.GRAY);
rb_no.setBackgroundColor(Color.GRAY);
selectedAnswers.set(i, "3");
break;
}
}
});
return view;
}
public List<String> getSelectedAnswers(){
return selectedAnswers;
}
public void clearSelectedAnswers(){
selectedAnswers = new ArrayList<String>();
backgroundColor = new ArrayList<Integer>();
for (int i = 0; i < questionsList.length; i++) {
selectedAnswers.add("3");
backgroundColor.add(Color.WHITE); // new
}
this.notifyDataSetChanged();
}
public void setBackgroundColor(List<Integer> backgroundColor_){ // new
this.backgroundColor = backgroundColor_;
this.notifyDataSetChanged();
}
}
3) layout_8.xml:---------
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:weightSum="100"
android:orientation="vertical">
<ListView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="90"
android:id="@+id/lv">
</ListView>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="70dp"
android:layout_weight="10"
android:layout_marginTop="10dp"
android:layout_marginBottom="10dp"
android:orientation="horizontal">
<Button
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="Submit"
android:layout_toStartOf="@id/v"
android:textAllCaps="false"
android:id="@+id/submit"/>
<View
android:layout_width="1dp"
android:layout_height="0dp"
android:id="@+id/v"
android:layout_centerInParent="true">
</View>
<Button
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="Clear"
android:layout_toEndOf="@id/v"
android:textAllCaps="false"
android:id="@+id/clear"/>
</RelativeLayout>
</LinearLayout>
4) list_items.xml:--------
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical">
<!-- TextView for displaying question-->
<TextView
android:id="@+id/question"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:textColor="#000"
android:textSize="30dp"
android:text="Which is your most favorite?"
/>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity"
android:id="@+id/main">
<RadioGroup
android:id="@+id/radio_group"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:orientation="horizontal">
<RadioButton
android:id="@+id/yes"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="20dp"
android:button="@null"
android:paddingHorizontal="30dp"
android:paddingVertical="5dp"
android:text="YES"
android:textSize="50dp" />
<RadioButton
android:id="@+id/no"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="20dp"
android:button="@null"
android:paddingHorizontal="30dp"
android:paddingVertical="5dp"
android:text="NO"
android:textSize="50dp" />
</RadioGroup>
</FrameLayout>
</LinearLayout>
【问题讨论】：
标签： java android listview android-viewholder android-radiogroup