更改listview上单击项的图像资源

Question

当我想要更改我点击的项目的图像时，我有列表问题。我尝试使用drawable更改背景颜色和文本颜色，但我无法更改ListView的图像。那么当我点击它时如何更改该图像呢？

我的目的是想要将橙色图像更改为白色图像。

ListAdapter

public class ListAdapter extends BaseAdapter {

    private String[] titles;
    private int[] images;
    private Context context;

    public ListAdapter(Context context, String[] titles, int[] images) {
        this.context = context;
        this.titles = titles;
        this.images = images;
    }

    @Override
    public int getCount() {
        return titles.length;
    }

    @Override
    public Object getItem(int position) {
        return titles[position];
    }

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        View view = null;
        if (convertView == null) {
            LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            view = inflater.inflate(R.layout.navigation_list_item, parent, false);
        } else {
            view = convertView;
        }

        TextView textView = (TextView) view.findViewById(R.id.tv_navigation_item);
        ImageView imageView = (ImageView) view.findViewById(R.id.iv_navigation_item);

        textView.setText(titles[position]);
        imageView.setImageResource(images[position]);

        return view;
    }
}

ListActivity

public class ListActivity extends AppCompatActivity {

    ListView listView;
    ListAdapter adapter;

    String [] title = new String[]{"Item A","Item B","Item C","Item D"};
    int [] image = new int[]{R.drawable.ic_android_red_500_24dp,
            R.drawable.ic_add_shopping_cart_red_500_24dp,
            R.drawable.ic_android_red_500_24dp,
            R.drawable.ic_accessibility_red_500_24dp};

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_list);

        listView = (ListView) findViewById(R.id.lv_listview);

        setNavigationList();

    }
    private void setNavigationList() {
        adapter = new ListAdapter(this, title, image);
        listView.setAdapter(adapter);
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

                view.setSelected(true);
            }
        });

    }
}

Answer 1

您可以在适配器上添加selectedPosition参数，并在点击

上更新活动

public class ListAdapter extends BaseAdapter {
    private String[] titles;
    private int[] images;
    private Context context;
    private int selectedPosition;


public ListAdapter(Context context, String[] titles, int[] images, int selectedPosition) {
    this.context = context;
    this.titles = titles;
    this.images = images;
    this.selectedPosition = selectedPosition;
}

public void updateSelectedPosition(int selectedPosition){
  this.selectedPosition = selectedPosition;
  notifyDataSetChanged();
}

@Override
public int getCount() {
    return titles.length;
}

@Override
public Object getItem(int position) {
    return titles[position];
}

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

@Override
public View getView(int position, View convertView, ViewGroup parent) {

    View view = null;
    if (convertView == null) {
        LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        view = inflater.inflate(R.layout.navigation_list_item, parent, false);
    } else {
        view = convertView;
    }

    TextView textView = (TextView) view.findViewById(R.id.tv_navigation_item);
    ImageView imageView = (ImageView) view.findViewById(R.id.iv_navigation_item);

    textView.setText(titles[position]);
    if(selectedPosition == position){
    // change the image view to orange here

    }else{
        imageView.setImageResource(images[position]);
    }


    return view;
}

然后在活动

public class ListActivity extends AppCompatActivity {

    ListView listView;
    ListAdapter adapter;

    String [] title = new String[]{"Item A","Item B","Item C","Item D"};
    int [] image = new int[]{R.drawable.ic_android_red_500_24dp,
            R.drawable.ic_add_shopping_cart_red_500_24dp,
            R.drawable.ic_android_red_500_24dp,
            R.drawable.ic_accessibility_red_500_24dp};

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_list);

        listView = (ListView) findViewById(R.id.lv_listview);

        setNavigationList();

    }
    private void setNavigationList() {
        adapter = new ListAdapter(this, title, image,-1);
        listView.setAdapter(adapter);
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                view.setSelected(true);
                adapter.updateSelectedPosition(position);
            }
        });

    }
}