[Android]一个选择图片的Demo

[fred-ye]

分享一个之前写的一个选择图片的Feature.

Activity 类

public class PickPictureActivity extends Activity {

    private static final int CODE_OPEN_GALLERY = 1;
    final static int KITCAT_REQUEST_PICK = 1001;
    private static final String TAG = "PickPictureActivity";

    private ArrayList<String> imageUrls = new ArrayList<String>();
    private GridView gvImages;
    public ImageLoader imageLoader = ImageLoader.getInstance();
    private PickPictureAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_pick_picture);
        gvImages = (GridView) findViewById(R.id.gv_add_pic);
        ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(getApplicationContext())
                                                                      .memoryCache(new WeakMemoryCache()).build();
        imageLoader.init(config);
        adapter = new PickPictureAdapter(PickPictureActivity.this);
        gvImages.setAdapter(adapter);
        Log.i("Activity", "onCreate execute");

    }
    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);
        imageUrls = savedInstanceState.getStringArrayList("imageUrls");
    }

    /**
     * Pick a existing picture from gallery.
     */
    public void pickPhotoFromGalley() {
        Log.i("PicPicture", "pic size" + imageUrls.size());
        if (android.os.Build.VERSION.SDK_INT < 19) {
            Intent intent = new Intent(Intent.ACTION_GET_CONTENT, null);
            intent.setType("image/*");
            intent.putExtra("return-data", true);
            startActivityForResult(intent, CODE_OPEN_GALLERY);
        } else {
            Intent intent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.INTERNAL_CONTENT_URI);
            intent.setType("image/*");
            startActivityForResult(intent, KITCAT_REQUEST_PICK);
        }
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        Log.i("Activity", "onActivityResult size: " + imageUrls.size() );
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode != RESULT_CANCELED && null != data) {
            Uri uri = data.getData();
            Log.i(TAG, "uri:" + uri);
            if (null != getRealPathFromURI(uri)) {
                Log.i(TAG, getRealPathFromURI(uri));
                imageUrls.add("file://" + getRealPathFromURI(uri));
                adapter.clearItems();
                adapter.addAllItems(imageUrls);
                gvImages.setAdapter(adapter);

            }
        }
    }

    public String getRealPathFromURI(Uri contentUri) {
        Cursor cursor = null;
        try {
            String[] proj = { MediaStore.Images.Media.DATA };
            cursor = getContentResolver().query(contentUri, proj, null, null, null);
            int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
            cursor.moveToFirst();
            return cursor.getString(column_index);
        } finally {
            if (cursor != null) {
                cursor.close();
            }
        }
    }
    @Override
    protected void onSaveInstanceState(Bundle outState) {
        outState.putStringArrayList("imageUrls", imageUrls);
        super.onSaveInstanceState(outState);
        Log.i("Activity", "onSaveInstanceState execute");
    }

}

值得说明的几点

• 本例子中图片的加载采用的是Universal-Image-Loader。通常在项目中关于它的配置和初始化应该写到ＡApp的Application中去，此处为了简单，就直接写在Activity中的，在实际项目中不可以这样写。
  • 在打开Gallery，选择图片时，系统有可能会将Activity销毁，为此需要覆盖其onSaveInstanceState(Bundle outState)方法，否则有可能在选好图片后，返回到当前Activity时发现之前选的图片丢失了。

    Adapter

public class PickPictureAdapter extends BaseAdapter {
    private Context context;
    private List<String> imageList = new ArrayList<String>();
    private ViewHolder holder;

    public PickPictureAdapter(Context context) {
        this.context = context;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        if (null == convertView) {
            holder = new ViewHolder();
            LayoutInflater inflater = (LayoutInflater) context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = inflater.inflate(R.layout.pick_picture_item, null, false);
            holder.ivAddPic = (ImageView)convertView.findViewById(R.id.iv_add_pic);
            holder.ivPic = (ImageView)convertView.findViewById(R.id.iv_my_image);
            convertView.setTag(holder);
        } else {
            holder = (ViewHolder) convertView.getTag();
        }
        if (position == imageList.size()) {
            holder.ivAddPic.setVisibility(View.VISIBLE);
            holder.ivPic.setVisibility(View.GONE);
            holder.ivAddPic.setOnClickListener(listener);
        } else {
            holder.ivPic.setVisibility(View.VISIBLE);
            holder.ivAddPic.setVisibility(View.GONE);
            if (null != getItem(position)) {
                ((PickPictureActivity) context).imageLoader.displayImage(imageList.get(position), holder.ivPic);
            }
        }
        return convertView;
    }

    private View.OnClickListener listener = new View.OnClickListener() {

        @Override
        public void onClick(View arg0) {
            PickPictureActivity activity = (PickPictureActivity) context;
            activity.pickPhotoFromGalley();
        }
    };

    class ViewHolder {
        public ImageView ivPic;
        public ImageView ivAddPic;
    }

    @Override
    public int getCount() {
        Log.i("Adapter", "image count:" + imageList.size());
        return imageList.size() + 1;
    }

    @Override
    public Object getItem(int position) {
        if (getCount() > 0) {
            return imageList.get(position);
        }
        return null;
    }

    @Override
    public long getItemId(int arg0) {
        return 0;
    }
    public void clearItems() {
        imageList.clear();
        notifyDataSetChanged();
    }
    public void addAllItems(List<String> refreshList) {
        imageList.addAll(refreshList);
        notifyDataSetChanged();
    }
}

看一下我们的 pic_picture_item.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" >

    <ImageView
        android:id="@+id/iv_my_image"
        android:layout_width="80dp"
        android:layout_height="80dp"
        android:src="@drawable/icon_default"
        android:scaleType="fitXY"
        android:visibility="gone"
        />
    <ImageView
        android:id="@+id/iv_add_pic"
        android:layout_width="80dp"
        android:layout_height="80dp"
        android:padding="20dp"
        android:background="@drawable/pick_picture_normal"
        android:src="@drawable/icon_add"
        android:visibility="gone"
        />

</RelativeLayout>

样式定义pick_picture_normal.xm

针对添加按钮周围的边框

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" >
    <solid android:color="@null" />
    <stroke
        android:dashGap="4dp"
        android:dashWidth="8dp"
        android:width="2dp"
        android:color="#c2c2c2" />
</shape>

上图