当屏幕滚动时,GridView中的项目会重复出现

Question

我正在使用GridView来显示用户可以选择的一组类别.网格的每个项目都由ImageView和TextView组成,两者都从服务器检索.触摸项目时,将启动另一个活动.

我以为一切都是正确的,直到我注意到当我滚动屏幕时有些重复.每当我向下滚动网格,然后向后滚动,它就会改变它的位置并重复.但即使我触摸了搞砸了,也会将正确的值发送到下一个活动.

查看LogCat,发生对服务器的任何重复请求.事实上,我在滚动时得到了这个:

06-28 12:36:38.554: D/dalvikvm(358): GC_EXTERNAL_ALLOC freed 2061 objects / 156024 bytes in 51ms
06-28 12:36:42.915: D/dalvikvm(358): GC_FOR_MALLOC freed 6590 objects / 737528 bytes in 57ms
06-28 12:38:26.725: D/dalvikvm(358): GC_EXTERNAL_ALLOC freed 5426 objects / 468176 bytes in 71ms
06-28 12:38:26.875: D/dalvikvm(358): GC_EXTERNAL_ALLOC freed 409 objects / 17480 bytes in 68ms

看起来每次我滚动,它都会重绘...

更新:它只在我第一次向下滚动GridView时重绘它.在此之后,所有的itens,包括重复的,都会保留在它的位置上.

我的java类:

public void proccess(){
    int qtdCategorias = json.length();
    imagens = new Drawable[qtdCategorias];
    categorias = new String[qtdCategorias];
    for (int i=0; i<qtdCategorias; i++){
        JSONArray c = json.optJSONArray(i);
        String urlAmigavel = null;
        String imagemSite = null;
        String nomeCategoria = null;
        try {
            urlAmigavel = c.getString(6);
            imagemSite = c.getString(3);
            nomeCategoria = c.getString(2);
        } catch (JSONException e) {
            Log.e("CategoriasJogarActivity", e.toString());
            e.printStackTrace();
        }
        categorias[i] = nomeCategoria;
        imagens[i] = getImagem(urlAmigavel, imagemSite);
    }


    gridview = (GridView) findViewById(R.id.include3);

    ImageAdapter imageAdapter = new ImageAdapter(ctx, imagens, categorias);

    gridview.setAdapter(imageAdapter);

    gridview.setOnItemClickListener(new OnItemClickListener() {
        public void onItemClick(AdapterView<?> parent, View v,
                int position, long id) {

            String name = null;
            String idt = null;
            try {
                JSONArray c = json.optJSONArray(position);
                name = c.getString(2);
                idt = c.getString(0);
            } catch (JSONException e) {
                Log.e("CategoriasJogarActivity",
                        "JSONException" + e.toString());
            }

            Intent in = new Intent(getApplicationContext(),
                    JogarActivity.class);
            in.putExtra(TAG_NAME, name);
            in.putExtra(TAG_ID, idt);
            in.putExtra(TAG_PRIMEIRAPERGUNTA, true);
            startActivity(in);

        }
    });
}


public Drawable getImagem(String urlAmigavel, String img) {
    String url = "http://www.qranio.com/pergunta/" + urlAmigavel + "/"+ img;
    InputStream is = null;
    try {
        URL urlImagem = new URL(url);
        is = (InputStream) getObjeto(urlImagem);
    } catch (MalformedURLException e1) {
        Log.e("CategoriasJogarActivity", e1.toString());
        e1.printStackTrace();
    }
    Drawable d = Drawable.createFromStream(is, "src");

    return d;
}

private Object getObjeto(URL url) {
    Object content = null;
    try {
        content = url.getContent();
    } catch (IOException e) {
        Log.e("CategoriasJogarActivity", e.toString());
        e.printStackTrace();
    }
    return content;
}

imageAdapter类

public class ImageAdapter extends BaseAdapter{
private Context mContext;
private final Drawable[] mThumbIds;
private final String[] mTextIds;


public ImageAdapter(Context c, Drawable[] d, String[] s) {
    mContext = c;
    mThumbIds = d;
    mTextIds = s;
}

public int getCount() {
    return mThumbIds.length;
}

public Object getItem(int position) {
    return null;
}

public long getItemId(int position) {
    return 0;
}

//create a new ImageView for each item referenced by the Adapter
public View getView(int position, View convertView, ViewGroup parent) {
    //ImageView imageView;
    View v;
    if (convertView == null) {  // if it's not recycled, initialize some attributes
        LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(     Context.LAYOUT_INFLATER_SERVICE );
        v = inflater.inflate(R.layout.gridview_item_layout, null);
        TextView text = (TextView)v.findViewById(R.id.grid_item_text);
        text.setText(mTextIds[position]);
        ImageView image = (ImageView)v.findViewById(R.id.grid_item_image);
        image.setImageDrawable(mThumbIds[position]);


    } else {

        v = (View) convertView;
    }


    return v;
}


}

gridview_item_layout xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/gridview_item_layout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
android:gravity="center_horizontal" >

<ImageView android:id="@+id/grid_item_image"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleType="fitCenter"
android:minHeight="100dip"
android:minWidth="100dip"
>
</ImageView>

<TextView android:id="@+id/grid_item_text"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="TextView"
android:gravity="center"
android:textColor="#F9A512"
android:textStyle="bold"
android:textSize="18dp"
>
</TextView>
</LinearLayout>

gridview xml

<?xml version="1.0" encoding="utf-8"?>
<GridView xmlns:android="http://schemas.android.com/apk/res/android" 
android:id="@+id/gridview"
android:layout_width="fill_parent" 
android:layout_height="fill_parent"
android:numColumns="auto_fit"
android:verticalSpacing="10dip"
android:horizontalSpacing="10dip"
android:stretchMode="columnWidth"
android:gravity="center"
android:background="#FFFFFF"
android:padding="5dip"
/>

我看到了关于同样问题的其他问题,但没有人回答.对于发生了什么的任何想法？

Answer 1

这是正常的,你看到相同的项目,你向下滚动GridView,因为在getView方法设置为可绘制的ImageView,只有当convertView是null(例如,用于当所看到的第一个元素GridView出现在屏幕上).如果convertView不是null,意味着您具有循环行视图,则不会设置正确的图像,并且您将保留先前在此循环视图上设置的图像.尝试修改这样的getView方法:

public View getView(int position, View convertView, ViewGroup parent) {
    View v;
    if (convertView == null) {  // if it's not recycled, initialize some attributes
        LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(     Context.LAYOUT_INFLATER_SERVICE );
        v = inflater.inflate(R.layout.gridview_item_layout, parent, false);
    } else {
        v = (View) convertView;
    }
    TextView text = (TextView)v.findViewById(R.id.grid_item_text);
    text.setText(mTextIds[position]);
    ImageView image = (ImageView)v.findViewById(R.id.grid_item_image);
    image.setImageDrawable(mThumbIds[position]);
    return v;
}

单击元素会显示正确的项目,因为您使用该position参数来检索数据.