java - ImageView 未根据 onActivityResult 中的更改进行更新

Question

我尝试过使用 Picasso 以及我在 stackoverflow 上可以找到的所有方法。我正在用相机拍摄图像并获取 onActivity 结果的值。仅当我退出并重新启动应用程序后，imageView 才会更新。我希望 imageview 在我眼前改变。所有代码似乎都不起作用。

我试过了

getActivity().runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    profile.setImageBitmap(thumbnail);
                }
            });

点击“确定”后相机 View 关闭时没有任何反应。

我也尝试过这个:

   Thread thread = new Thread()
            {
                @Override
                public void run() {
                    getActivity().runOnUiThread(new Runnable() //run on ui thread
                    {
                        public void run()
                        {
                            profile.setImageBitmap(thumbnail);

                        }
                    });
                }
            };
            thread.start();

但 UI 没有改变，图像保持不变。

我尝试了异步任务，Picasso 也不起作用。

不知道该怎么做，已经有一段时间了，我非常沮丧

这是使用这两种技术的代码:

public void onActivityResult(int requestCode, int resultCode, Intent data) {

        if (requestCode == 1 && data != null) {
            final Bitmap thumbnail = (Bitmap) data.getExtras().get("data");
            ByteArrayOutputStream bytes = new ByteArrayOutputStream();
            thumbnail.compress(Bitmap.CompressFormat.JPEG, 90, bytes);
            final File destination = new File(Environment.getExternalStorageDirectory().getAbsolutePath(), "temp.jpg");
            FileOutputStream fo;
            try {
                fo = new FileOutputStream(destination);
                fo.write(bytes.toByteArray());
                fo.close();
            } catch (IOException e) {
                e.printStackTrace();
            }

            uploadProfilePicToS3(destination.getAbsolutePath());

            //this doesn't work
            Thread thread = new Thread()
            {
                @Override
                public void run() {
                    getActivity().runOnUiThread(new Runnable() //run on ui thread
                    {
                        public void run()
                        {
                            profile.setImageBitmap(thumbnail);

                        }
                    });
                }
            };
            thread.start();

            //not working either!
            getActivity().runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    profile.setImageBitmap(thumbnail);
                }
            });

Answer 1

ImageView 未更新的原因是 1) 只要您将图像保存到同一目标，Android 就会加载缓存中的上一张图像 2) onActivityResult 在 onResume 之前调用。这意味着当调用 onResume 时，加载到 ImageView 中的图像将会丢失。

第一个问题可以通过Glide的signature很好的解决，第二个问题可以通过onSavedInstanceState()解决。

更改图像时创建Glide 签名。每次更改都应该有所不同，例如当前时间。然后在加载图像时应用签名。

public void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == 1 && data != null) {
        final Bitmap bitmap = (Bitmap) data.getExtras().get("data");
        ByteArrayOutputStream bytes = new ByteArrayOutputStream();
        bitmap.compress(Bitmap.CompressFormat.JPEG, 90, bytes);
        final File destination = new File(
            Environment.getExternalStorageDirectory()
            .getAbsolutePath(), "temp.jpg");
        FileOutputStream fo;
        try {
            fo = new FileOutputStream(destination);
            fo.write(bytes.toByteArray());
            fo.flush();
        } catch (IOException e) {
            e.printStackTrace();
        }
    Uri uri = Uri.fromFile(destination)

    //Create your signature
    SimpleDateFormat dateFormat = new SimpleDateFormat("yyMMddHHmmss", 
        Locale.getDefault());
    String timeStamp = dateFormat.format(new Date());
    newImageSignature =  new RequestOptions()
        .signature(new ObjectKey(timeStamp));

    //Load your image
    Glide.with(yourActivity.this) // Or Fragment
        .load(bitmap) // Or Uri
        .apply(newImageSignature)
        .into(imageView);

    // You can save the uri and signature to Firebase Database, 
    // and your image to Storage here

然后将新的签名保存在onSaveInstanceState()

中

@Override
protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    if (newImageSignature != null) {
        outState.putString("IMAGE_SIGNATURE”, newImageSignature.toString());
        outState.putString("IMAGE_URI”, uri.toString());
    }
}

现在您可以在 onCreate() 中检索签名

Uri ImageUri;
ImageView imageView;
RequestOptions imageSignature;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    // Retrieve your saved parameters. Or get them from a database.
    if (savedInstanceState != null){
        imageSignature = new RequestOptions()
            .signature(new 
             ObjectKey(savedInstanceState.getString("IMAGE_SIGNATURE"))); 
        imageUri = Uri.parse(savedInstanceState.getString("IMAGE_URI"));

    // Instantiate your imageview

    // Load image
    if(imageUri != null && imageSignature != null){
        Glide.with(yourActivity.this) // Or Fragment
        .load(bitmap) // Or Uri
        .apply(newImageSignature)
        .into(imageView);
    }
}

注意:我刚刚写了这个，尚未测试。希望它能提供