如何从意图中获取多张图片

Question

我想启动一个选择多个图像的意图。 例如，当意图将您指向图库以选择图像时，您长按并选择几个图像。我想获取这些图像的 URI。 我怎样才能做到这一点？ 感谢帮助

Answer 1

没有默认的方法来做到这一点。 这是我在我的项目中为此创建的一个活动：

public class GalleryActivity extends AtionbarActivity {
    // -----------------------------------------------------------------------
    //
    // Constants
    //
    // -----------------------------------------------------------------------
    public static final String EXTRA_SELECTED_ITEMS = "EXTRA_SELECTED_ITEMS";
    public static final String EXTRA_SELECT_MODE_SINGLE = "EXTRA_SELECT_MODE_SINGLE";
    // -----------------------------------------------------------------------
    //
    // Fields
    //
    // -----------------------------------------------------------------------
    private GridView mGridView;

    private GalleryAdapter mAdapter;

    private boolean mSelectSingle = false;

    // -----------------------------------------------------------------------
    //
    // Methods
    //
    // -----------------------------------------------------------------------
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_gallery);

        mSelectSingle = getIntent().getBooleanExtra(EXTRA_SELECT_MODE_SINGLE,
                false);

        findViews();
        initViews();

        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    }

    private void findViews() {
        mGridView = (GridView) findViewById(R.id.activity_gallery_gridview);
    }

    private void initViews() {
        mAdapter = new GalleryAdapter(this, R.layout.grid_item_gallery_image,
                mSelectSingle);
        mGridView.setAdapter(mAdapter);

        mGridView.setOnItemClickListener(mImageClickListener);
    }

    private void updateGrid() {
        Uri uri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
        String[] projection = { MediaStore.Images.Media.DATA,
                MediaStore.Images.Media.DATE_TAKEN,
                MediaStore.Images.Media.LATITUDE,
                MediaStore.Images.Media.LONGITUDE };
        Cursor cursor = getContentResolver().query(uri, projection, null, null,
                null);

        ArrayList<GalleryImage> list = new ArrayList<GalleryImage>();
        if (cursor.moveToFirst())
            while (cursor.moveToNext()) {
                GalleryImage image = new GalleryImage();
                int columnIndex = cursor
                        .getColumnIndex(MediaStore.Images.Media.DATA);
                image.path = cursor.getString(columnIndex);

                columnIndex = cursor
                        .getColumnIndex(MediaStore.Images.Media.DATE_TAKEN);
                image.date = new Date(cursor.getLong(columnIndex));

                columnIndex = cursor
                        .getColumnIndex(MediaStore.Images.Media.LATITUDE);
                image.lat = cursor.getDouble(columnIndex);

                columnIndex = cursor
                        .getColumnIndex(MediaStore.Images.Media.LONGITUDE);
                image.lng = cursor.getDouble(columnIndex);

                list.add(image);
            }
        mAdapter.setItems(list);
        cursor.close();
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        mAdapter.onSaveInstanceState(outState);
        super.onSaveInstanceState(outState);
    }

    @Override
    public void onRestoreInstanceState(@NotNull Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);
        mAdapter.onRestoreInstanceState(savedInstanceState);
    }

    @Override
    public void onResume() {
        super.onResume();
        updateGrid();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        super.onCreateOptionsMenu(menu);
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.gallery_menu, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
        case android.R.id.home:
            finish();
            return true;
        case R.id.menu_confirm:
            Intent intent = new Intent();
            intent.putExtra(EXTRA_SELECTED_ITEMS, mAdapter.getSelectedItems());
            setResult(RESULT_OK, intent);
            finish();
            return true;
        default:
            return super.onOptionsItemSelected(item);
        }
    }

    // -----------------------------------------------------------------------
    //
    // Listeners
    //
    // -----------------------------------------------------------------------

    private OnItemClickListener mImageClickListener = new OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
                long arg3) {
            mAdapter.applySelection(arg2);
        }
    };
}

我使用的适配器（您可以创建自己的）：

public class GalleryAdapter extends BaseAdapter {
    // -----------------------------------------------------------------------
    //
    // Constants
    //
    // -----------------------------------------------------------------------
    private static final String EXTRA_SELECTED_ITEMS = "EXTRA_SELECTED_ITEMS";

    // -----------------------------------------------------------------------
    //
    // Fields
    //
    // -----------------------------------------------------------------------
    private ArrayList<GalleryImage> mItems;
    private ArrayList<GalleryImage> mSelectedItems;
    private LayoutInflater mInflater;
    private int mResId;
    private boolean mSelectSingle;

    // -----------------------------------------------------------------------
    //
    // Constructor
    //
    // -----------------------------------------------------------------------
    public GalleryAdapter(Context context, int resource, boolean selectMode) {
        mResId = resource;
        mItems = new ArrayList<GalleryImage>();
        mSelectedItems = new ArrayList<GalleryImage>();
        mSelectSingle = selectMode;

        mInflater = LayoutInflater.from(context);
    }

    // -----------------------------------------------------------------------
    //
    // Methods
    //
    // -----------------------------------------------------------------------
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        GalleryImage item = (GalleryImage) getItem(position);
        if (convertView == null)
            convertView = mInflater.inflate(mResId, parent, false);

        ImageView thumbnail = (ImageView) ViewHolder.get(convertView,
                R.id.grid_item_gallery_image);
        String thumbTag = (String) thumbnail.getTag();
        if (thumbTag == null || !thumbTag.equals(item.path))
            ImageManager.displayImage("file:/" + item.path, thumbnail);
        thumbnail.setTag(item.path);

        ImageView selection = (ImageView) ViewHolder.get(convertView,
                R.id.grid_item_gallery_selection);
        selection.setVisibility(mSelectedItems.contains(item) ? View.VISIBLE
                : View.GONE);

        return convertView;
    }

    public void setItems(ArrayList<GalleryImage> items) {
        mItems = items;
        notifyDataSetChanged();
    }

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

    @Override
    public Object getItem(int index) {
        return mItems.get(index);
    }

    @Override
    public long getItemId(int arg0) {
        return 0;
    }

    public void applySelection(int position) {
        GalleryImage image = mItems.get(position);
        if (mSelectSingle)
            mSelectedItems.clear();
        if (!mSelectedItems.contains(image))
            mSelectedItems.add(image);
        else
            mSelectedItems.remove(image);
        notifyDataSetChanged();
    }

    public void onRestoreInstanceState(Bundle savedInstanceState) {
        mSelectedItems = savedInstanceState
                .getParcelableArrayList(EXTRA_SELECTED_ITEMS);
        notifyDataSetChanged();
    }

    public void onSaveInstanceState(Bundle outState) {
        outState.putParcelableArrayList(EXTRA_SELECTED_ITEMS, mSelectedItems);
    }

    public ArrayList<GalleryImage> getSelectedItems() {
        return mSelectedItems;
    }
}

还有一个我用来存储图像数据的结构：

public class GalleryImage implements Parcelable {
    public String path;
    public Date date;
    public double lat;
    public double lng;

    public GalleryImage() {

    }

    public GalleryImage(String path, Date date, double lat, double lng) {
        this.path = path;
        this.date = date;
        this.lat = lat;
        this.lng = lng;
    }

    public GalleryImage(Parcel in) {
        this.path = in.readString();
        this.date = new Date(in.readLong());
        this.lat = in.readDouble();
        this.lng = in.readDouble();
    }

    @Override
    public boolean equals(Object o) {
        return ((GalleryImage) o).path.equals(path);
    }

    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        dest.writeString(path);
        dest.writeLong(date.getTime());
        dest.writeDouble(lat);
        dest.writeDouble(lng);
    }

    public static final Parcelable.Creator<GalleryImage> CREATOR = new Parcelable.Creator<GalleryImage>() {
        public GalleryImage createFromParcel(Parcel in) {
            return new GalleryImage(in);
        }

        public GalleryImage[] newArray(int size) {
            return new GalleryImage[size];
        }
    };
}   

您可以通过将意图中的EXTRA_SELECT_MODE_SINGLE 设置为true 或false 来指定是否需要多选/单选模式。这段代码将是一个很好的起点。