Question

我只想将预定文件中的照片添加到GridView，我无法弄清楚如何执行此操作。我有一个Adapter处理我从 this example学到的GridView，我无法弄清楚如何将mThumbIds数组设置为文件中的图像。我想我必须使用类似ImageView.setImageUri(Uri.fromFile(new File("myPath")));而不是setImageResource的内容，但我可能错了。这是我第一次做这样的事情，真的很感激任何帮助！

修改

当前代码:(有了这个，我得到一个NullPointer：for(File f : dir.listFiles()){在文档中它表示如果它不是目录则返回null。新文件（...）中的代码是同样我用来创建目录，所以我知道路径是正确的，当应用程序启动它创建目录，文件夹中没有图片，直到用户拿一个。我当时认为这是问题，但它仍然关闭，当有目录中的照片。）

public static class HomeFragment extends Fragment{

    public HomeFragment(){

    }
    View rootView;
    GridView gridView;
    List<Drawable> list;
    File dir = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM), "MyAppFolder");
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup contatiner,
            Bundle savedInstanceState){

        for(File f : dir.listFiles()){
            Bitmap original = BitmapFactory.decodeFile(f.getAbsolutePath());
            Drawable drawable = new BitmapDrawable(getResources(), original);
            list.add(drawable);
        }
        rootView = inflater.inflate(R.layout.home_layout,
                contatiner, false);
        gridView = (GridView) rootView.findViewById(R.id.homeGridView);
        gridView.setAdapter(new HomeAdapter(getActivity(), list));


        return rootView;
    }

}


public class HomeAdapter extends BaseAdapter {
private Context mContext;
private List<Drawable> mPictures;

public HomeAdapter(Context c, List<Drawable> list) {
    mContext = c;
    mPictures = list;
}

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

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

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


public View getView(int position, View convertView, ViewGroup parent) {
    ImageView imageView;
    if (convertView == null) { 
        imageView = new ImageView(mContext);
        imageView.setLayoutParams(new GridView.LayoutParams(110, 110));
        imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
        imageView.setPadding(8, 8, 8, 8);
    } else {
        imageView = (ImageView) convertView;
    }

    imageView.setImageDrawable(mPictures.get(position));
    return imageView;
}
}

Answer 1

您可以使用BitmapFactory.decodeFile(filePath)获取位图：

Bitmap original = BitmapFactory.decodeFile(filePath);

// Scale the Bitmap if needed       
Bitmap scaled = Bitmap.createScaledBitmap(original, newWidth, newHeight, true);

从此位图创建Drawable：

// Use mContext.getResources if you are doing this in the Adapter
Drawable drawable = new BitmapDrawable(getResources(), scaled);

更改type的{{1}}：

mThumbIds

使用private Drawable[] mThumbIds = { drawable1, drawable2, drawable3....... };：

ImageView.setImageDrawable(Drawable)

更好的方法是在Activity中创建imageView.setImageDrawable(mThumbIds[position]);数组，并在初始化mThumbIds时将其作为参数传递。您需要更改ImageAdapter构造函数。

修改1：

您可以使用ImageAdapter's来克服未知大小问题。我将假设您能够创建List<Drawable>个对象并使用上述信息对其进行初始化：

Drawable

将您的Drawable d1 = .... Drawable d2 = .... Drawable d3 = .... .... .... List<Drawable> list = new ArrayList<Drawable>(); list.add(d1); list.add(d2); .... gridview.setAdapter(new ImageAdapter(this, list));代码更改为：

ImageAdapter's

在public class ImageAdapter extends BaseAdapter { private Context mContext; private List<Drawable> mThumbIds; public ImageAdapter(Context c, List<Drawable> list) { mContext = c; mThumbIds = list; } public int getCount() { return mThumbIds.size(); } .... ....：

ImageAdapter's getView()

卸下：

imageView.setImageDrawable(mThumbIds.get(position));

将文件中的图像设置为GridView

1 个答案: