Imageview 在滚动列表视图上自动更改

Question

我是 android 的新手，面临一个非常常见的列表视图问题，我用谷歌搜索了很多，但没有找到任何对我有用的东西 case.Hope 你们告诉我正确的 direction.Whenever我正在将我的图像从 "plus" 更改为 "tick" 单击我的最后一个项目图像也在滚动时自动更改。

我的list_comapare_productXMl:-

<?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:background="@color/white_color"
    android:orientation="vertical" >

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="20dp"
        android:background="@color/white_color"
        android:gravity="center_vertical" >

        <ImageView
            android:id="@+id/img_product"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentLeft="true"
            android:layout_centerHorizontal="true"
            android:layout_centerVertical="true"
            android:src="@drawable/crane" />

        <com.mss.skyjack.custom.views.SkyjackCustomTextview
            android:id="@+id/tv_product_name"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerHorizontal="true"
            android:layout_centerVertical="true"
            android:gravity="center"
            android:text="test"
            android:textAppearance="?android:attr/textAppearanceMedium" />

        <ImageView
            android:id="@+id/img_plus"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentRight="true"
            android:layout_centerHorizontal="true"
            android:layout_centerVertical="true"
            android:src="@drawable/plus" />
    </RelativeLayout>

    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="20dp"
        android:background="@color/black_color" />

</LinearLayout>

这是我的适配器：-

import java.util.List;

import android.app.Activity;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;



public class ComapreProductSelectionAdapter extends BaseAdapter {
 Activity activity;
 List<SelectorTest> listSelector;
 private LayoutInflater mLayoutInflater;

 public ComapreProductSelectionAdapter(Activity activity,
   List<SelectorTest> listSelector) {
  this.activity = activity;
  this.listSelector = listSelector;
  mLayoutInflater = (LayoutInflater) activity
    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
 }

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

 @Override
 public SelectorTest getItem(int position) {
  return listSelector.get(position);
 }

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

 @Override
 public View getView(int position, View convertView, ViewGroup parent) {
  final ViewHolder viewHolder;
  final int i = position;
  final SelectorTest listItem = listSelector.get(position);

  if (convertView == null) {
   convertView = mLayoutInflater.inflate(
     R.layout.list_comapare_product, parent, false);
   viewHolder = new ViewHolder();
   viewHolder.tvProductName = (TextView) convertView
     .findViewById(R.id.tv_product_name);
   viewHolder.imgProduct = (ImageView) convertView
     .findViewById(R.id.img_product);
   viewHolder.imgadd = (ImageView) convertView
     .findViewById(R.id.img_plus);

   convertView.setTag(viewHolder);

  } else {
   viewHolder = (ViewHolder) convertView.getTag();
  }
  viewHolder.imgadd.setOnClickListener(new OnClickListener() {

   @Override
   public void onClick(View v) {
    if (viewHolder.imgadd.getDrawable().getConstantState() == activity
      .getResources().getDrawable(R.drawable.plus)
      .getConstantState()) {
     viewHolder.imgadd.setImageResource(R.drawable.tick);
    } else {
     viewHolder.imgadd.setImageResource(R.drawable.plus);
    }
    
   }
  });
  return convertView;
 }

 static class ViewHolder {
  TextView tvProductName;
  ImageView imgProduct, imgadd;
  View viewRightLine;
 }

}

谢谢。

Answer 1

您需要跟踪哪些项目已经 "ticked"。我复制了您的适配器并进行了必要的更改。您只需复制粘贴代码即可。

import java.util.List;

import android.app.Activity;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;



public class ComapreProductSelectionAdapter extends BaseAdapter {
    Activity activity;
    List<SelectorTest> listSelector;
    private LayoutInflater mLayoutInflater;
    private ArrayList<Integer> tickedItems = new ArrayList<Integer>();

    public ComapreProductSelectionAdapter(Activity activity,
            List<SelectorTest> listSelector) {
        this.activity = activity;
        this.listSelector = listSelector;
        mLayoutInflater = (LayoutInflater) activity
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

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

    @Override
    public SelectorTest getItem(int position) {
        return listSelector.get(position);
    }

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        final ViewHolder viewHolder;
        final int i = position;
        final SelectorTest listItem = listSelector.get(position);

        if (convertView == null) {
            convertView = mLayoutInflater.inflate(
                    R.layout.list_comapare_product, parent, false);
            viewHolder = new ViewHolder();
            viewHolder.tvProductName = (TextView) convertView
                    .findViewById(R.id.tv_product_name);
            viewHolder.imgProduct = (ImageView) convertView
                    .findViewById(R.id.img_product);
            viewHolder.imgadd = (ImageView) convertView
                    .findViewById(R.id.img_plus);

            convertView.setTag(viewHolder);

        } else {
            viewHolder = (ViewHolder) convertView.getTag();
        }

        viewHolder.imgadd.setTag(position);

        viewHolder.imgadd.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                if(tickedItems.contains((Integer)v.getTag()) {
                   //Already ticked, set to plus
                    viewHolder.imgadd.setImageDrawable(activity.getResources().getDrawable(R.drawable.plus));
                    tickedItems.remove((Integer)v.getTag());
           } else {
                    tickedItems.add((Integer)v.getTag());
                    viewHolder.imgadd.setImageDrawable(activity.getResources().getDrawable(R.drawable.tick));
            }

            }
        });

        if(tickedItems.contains(position))
            viewHolder.imgadd.setImageDrawable(activity.getResources().getDrawable(R.drawable.tick));
        else
            viewHolder.imgadd.setImageDrawable(activity.getResources().getDrawable(R.drawable.plus));
        return convertView;
    }

    static class ViewHolder {
        TextView tvProductName;
        ImageView imgProduct, imgadd;
        View viewRightLine;
    }

}

另外，不要使用 ImageView.setImageResource()，因为它效率低下。

引自 Android 文档关于 ImageView.setImageReource()

This does Bitmap reading and decoding on the UI thread, which can cause a latency hiccup. If that's a concern, consider using setImageDrawable(android.graphics.drawable.Drawable) or setImageBitmap(android.graphics.Bitmap) and BitmapFactory instead.

Imageview 在滚动列表视图上自动更改

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