208_打开相册选择图片并返回_addcategory 仅仅打开相册-优快云博客

本文链接：https://blog.youkuaiyun.com/qq_33781658/article/details/52345039

本文介绍如何在Android应用中实现从设备相册选择图片，并将所选图片显示在ImageView上。通过创建Intent并使用特定Action及URI，启动相册供用户选择图片。之后通过onActivityResult接收用户选择的图片数据，并进行适配处理后展示。

208_打开相册选择图片并返回

刚刚只是打开了相册

没有进行操作

现在我们把相册里的图片返回过来

然后设置到我们的一个ImageView里面

//先创建一个intent
//给一个action,再给一个uri
//action给Intent.ACTION_PICK
//uri给android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI
Intent intent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);

//然后设置一个type为"image/*"
intent.setType("image/*");

//启动activity
startActivityForResult(intent, 0);

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    Uri uri = data.getData();
    try {
        Bitmap bitmap = getBitmapFormUri(this, uri);

        mIv.setImageBitmap(bitmap);
    } catch (IOException e) {

    }
}

public Bitmap getBitmapFormUri(Activity ac, Uri uri) throws FileNotFoundException, IOException {
    InputStream input = ac.getContentResolver().openInputStream(uri);
    BitmapFactory.Options onlyBoundsOptions = new BitmapFactory.Options();
    onlyBoundsOptions.inJustDecodeBounds = true;
    onlyBoundsOptions.inDither = true;//optional
    onlyBoundsOptions.inPreferredConfig = Bitmap.Config.ARGB_8888;//optional
    BitmapFactory.decodeStream(input, null, onlyBoundsOptions);
    input.close();
    int originalWidth = onlyBoundsOptions.outWidth;
    int originalHeight = onlyBoundsOptions.outHeight;
    if ((originalWidth == -1) || (originalHeight == -1))
        return null;
    //图片分辨率以480x800为标准
    float hh = 800f;//这里设置高度为800f
    float ww = 480f;//这里设置宽度为480f
    //缩放比。由于是固定比例缩放，只用高或者宽其中一个数据进行计算即可
    int be = 1;//be=1表示不缩放
    if (originalWidth > originalHeight && originalWidth > ww) {//如果宽度大的话根据宽度固定大小缩放
        be = (int) (originalWidth / ww);
    } else if (originalWidth < originalHeight && originalHeight > hh) {//如果高度高的话根据宽度固定大小缩放
        be = (int) (originalHeight / hh);
    }
    if (be <= 0)
        be = 1;
    //比例压缩
    BitmapFactory.Options bitmapOptions = new BitmapFactory.Options();
    bitmapOptions.inSampleSize = be;//设置缩放比例
    bitmapOptions.inDither = true;//optional
    bitmapOptions.inPreferredConfig = Bitmap.Config.ARGB_8888;//optional
    input = ac.getContentResolver().openInputStream(uri);
    Bitmap bitmap = BitmapFactory.decodeStream(input, null, bitmapOptions);
    input.close();

    return bitmap;
}