Question

我正在尝试在gridview中交换图像并制作此代码：

        grd.setOnItemClickListener(new OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            counter ++;
            if(counter % 1 == 0){
                firstclick = position;
                data1 = crops.get(position);                    
            }                   
            else if(counter % 2 ==0){
                Bitmap swapImage = crops.get(position);
                crops.set(position, crops.get(firstclick));
                crops.set(firstclick, swapImage);
                grd.invalidateViews();
            }
        }
    });

我不明白为什么这段代码不起作用。当我启动我的android时，我点击它们时瓷砖不会交换。我的imageadapter看起来像这样：

public ArrayList<ImageView> pics;
private ArrayList<Bitmap> crops;
private Context mContext;

public ImageAdapter(Context c, ArrayList<Bitmap> crops) {
    mContext = c;
    this.crops = crops;      
}

public int getCount() {
    return crops.size();
}

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;
    if (convertView == null) {  // if it's not recycled, initialize some attributes
        imageView = new ImageView(mContext);
        imageView.setLayoutParams(new GridView.LayoutParams(85, 85));
        imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
        imageView.setPadding(8, 8, 8, 8);
    } else {
        imageView = (ImageView) convertView;
    }

    imageView.setImageBitmap(crops.get(position));
    return imageView;
}
public void getpics(){
    for(int i = 0; i<getCount();i++){
        ImageView img = new ImageView(mContext);
        img.setImageBitmap(crops.get(i));
        img.setTag(i);
        pics.add(img);
        img = null;         
    }
}

}

首先，我想尝试互相交换图像，然后我想尝试仅在我的bitmaparraylist中交换一个特定的图块。

Answer 1

counter%1总是零改变你对这些语句的陈述：

if (counter%2==1) {
 ....
} else {
 ...
}

并且对于交换邻居项目，如果计数器从零开始，请执行以下操作：

if (counter % 2 == 1) {
      // swap item at counter with item at counter-1
      ...
}

如果计数器从1开始，请执行以下操作：

if (counter % 2 == 0) {
      //swap item at counter with item at counter-1
      ...
}

Answer 2

就这样做。

在GridView中，当您想要更改项目时，您只需更改链接到GridView的适配器。

例如，交换两个项目：（GridAdapter extends ArrayAdapter）

＆＃13;

GridAdapter adapter = (GridAdapter)gridv.getAdapter();
String firstItem = adapter.getItem(firstPosition);
String secondItem = adapter.getItem(secondPosition);
adapter.remove(firstItem);
adapter.insert(firstItem, secondPosition);
adapter.remove(secondItem);
adapter.insert(secondItem, firstPosition);

＆＃13;

您还可以通过覆盖getView（）来更改自定义适配器中的其他内容。

如何在gridview中交换图像

2 个答案: