android - 来自 ArrayAdapter 的 OnRatingBarChangeListener

Question

我创建了一个带有“lineContent”布局的“InterestLine”类，该布局包含一个 TextView 和一个 RatingBar。然后我创建了一个适配器来在主布局上创建一个 InterestLines ListView ，这样用户就可以看到 TextView 列表 + 旁边的评级栏，并对每个元素进行评级。

public class MainActivity extends ActionBarActivity implements RatingBar.OnRatingBarChangeListener{

private String gender,age,output;
private List<InterestLine> lines;
private Button doneBtn;
private ListView lv;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);

    String[] interest_list = {"//the list of text views//"};

    lv=(ListView)findViewById(R.id.list_view);

    lines=new ArrayList<InterestLine>();
    for(String il:interest_list)
        lines.add(new InterestLine(il));

    ArrayAdapter<InterestLine> adapter=new ArrayAdapter<InterestLine>(this, R.layout.linecontent, R.id.tv1, lines);
    lv.setAdapter(adapter);

    doneBtn=(Button)findViewById(R.id.button1);
    doneBtn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            // collect stars (interests)
            for(InterestLine il : lines) 
                output = output + il.getInterestName() + ":" + il.getNumberOfStars() + ",";

            Log.i("OUTPUT", output);
        }
    });
}

@Override
public void onRatingChanged(RatingBar ratingBar, float rating,
        boolean fromUser) {
    // TODO Auto-generated method stub

}

我想通过点击按钮来收集用户在RatingBars上介绍的所有评分，尝试了几种方法都没有成功。希望你能帮我解决这个问题。谢谢

主要 Activity 的布局:

 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >
    <ListView
        android:id="@+id/list_view"
        android:layout_width="wrap_content"
        android:layout_height="0dp"
        android:layout_weight="0.86" >
    </ListView>
    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/done_btn"
        android:layout_gravity="right" />
</LinearLayout>

以及行的布局:

<LinearLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="fill_parent"
  android:layout_height="match_parent">    
    <TextView 
        android:text="@string/line_text"
        android:id="@+id/tv1" 
        android:layout_width="wrap_content" 
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical"
        android:textSize="18sp"
        android:width="120sp" />
    <RatingBar
        android:id="@+id/ratingBar1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:stepSize="1.0"
        android:layout_gravity="center_vertical" />
</LinearLayout>

Answer 1

我花了一段时间才弄明白。对于这种复杂的布局，你不应该使用 ArrayAdapter。您应该使自定义适配器从 BaseAdapter 扩展。这是有效的自定义适配器和 Activity 代码。

评级适配器

public class RatingAdapter extends BaseAdapter{

 List<InterestLine> mInterestLineArrayList;
 private RatingListener ratingListener;
 public RatingAdapter(List<InterestLine> interestLines) {
  mInterestLineArrayList = interestLines;
}

 @Override public int getCount() {
   return mInterestLineArrayList.size();
 }

 @Override public InterestLine getItem(int i) {
   return mInterestLineArrayList.get(i);
 }

 @Override public long getItemId(int i) {
   return i;
 }

 @Override public View getView(int i, View view, ViewGroup viewGroup)  {
   RatingViewHolder ratingViewHolder;
   if(view==null){
     view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.linecontent,viewGroup,false);
     ratingViewHolder = new RatingViewHolder(view);
     view.setTag(ratingViewHolder);
   }else{
     ratingViewHolder = (RatingViewHolder) view.getTag();
   }
   ratingViewHolder.titleView.setText(getItem(i).getInterestName());
   ratingViewHolder.ratingBar.setNumStars(getItem(i).getNumberOfStars());
   ratingViewHolder.currentPosition = i;
   return view;
 }

 public void setOnItemRatingChangeListener(RatingListener ratingListener){
   this.ratingListener = ratingListener;
 }

 public interface RatingListener{
   void onRatingBarClicked(RatingBar ratingBar, float v, boolean b,int position);
 }
 class RatingViewHolder  implements RatingBar.OnRatingBarChangeListener{
   private TextView titleView;
   private RatingBar ratingBar;
   private int currentPosition;
   public RatingViewHolder(View view){
     titleView = (TextView) view.findViewById(R.id.tv1);
     ratingBar = (RatingBar) view.findViewById(R.id.ratingBar1);
     ratingBar.setOnRatingBarChangeListener(this);
   }

   @Override public void onRatingChanged(RatingBar ratingBar, float v, boolean b) {
     if(ratingListener!=null){
       ratingListener.onRatingBarClicked(ratingBar,v,b,currentPosition);
      }
    }
  }
}

主 Activity

public class MainActivity extends AppCompatActivity{

private String gender, age, output;
private List<InterestLine> lines;
private Button doneBtn;
private ListView lv;

@Override protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);

  setContentView(R.layout.activity_main);

  String[] interest_list = { "Hope","it's","ok" };

  lv = (ListView) findViewById(R.id.list_view);

  lines = new ArrayList<>();
  for (String il : interest_list) {
    InterestLine interestLine = new InterestLine();
    interestLine.setInterestName(il);
    lines.add(interestLine);
  }

  RatingAdapter adapter = new RatingAdapter(lines);
  lv.setAdapter(adapter);
  adapter.setOnItemRatingChangeListener(new RatingAdapter.RatingListener() {
    @Override public void onRatingBarClicked(RatingBar ratingBar, float v, boolean b,int position) {
      lines.get(position).setNumberOfStars((int)v);
    }
  });
  doneBtn = (Button) findViewById(R.id.button1);
  doneBtn.setOnClickListener(new View.OnClickListener() {
    @Override public void onClick(View v) {
      // collect stars (interests)
      output = "";
      for (InterestLine il : lines) {
        output = il.getInterestName() + " " + il.getNumberOfStars();
        Log.i("OUTPUT", output);
      }
    }
  });
}

基本上，您创建一个自定义适配器，您可以在其中获取每个评级栏的实例。然后在该评级条上设置 OnRatingChangeListener。然后，您可以在回调的帮助下从 Activity 中获得所需的评分值。这里棘手的部分是从适配器获取项目位置。我通过将当前项目位置存储在 viewholder 中解决了这个问题。不管怎样，我还想指出，对于这种事情，使用回收器 View 会容易得多。