问题 下载后从谷歌照片库中检索图像

您无法从谷歌驱动器下载图像下面是从驱动器下载图像或文件的步骤。

要从谷歌硬盘下载图像或文件，您需要一个库

• 谷歌的API服务驱动-V2-rev9-1.8.0-beta.jar（）

设置控制台

• 接下来去 谷歌康寿

• 制作一个新项目。在服务下，您需要打开两件事：DRIVE API和DRIVE SDK！它们是分开的，一个不会自动转动另一个，你必须同时打开！ （弄清楚这一点至少浪费了我20个小时的时间。）

• 仍在控制台上，转到API Access。创建一个客户端，使其成为Android应用程序。给它你的包ID。我不认为指纹的东西实际上是重要的，因为我很确定我使用了错误的指纹，但是无论如何都要尝试做到这一点（Google为它提供了说明。）

• 它会产生一个 客户ID。你需要那个。抓住它。

ANDROID代码 - 设置和上传

• 首先，获取身份验证令牌：

  AccountManager am = AccountManager.get（activity）;     am.getAuthToken（am.getAccounts（））[0]，         “oauth2：”+ DriveScopes.DRIVE，         新捆绑（），         真正，         新的OnTokenAcquired（），         空值）;

接下来，OnTokenAcquired（）需要设置如下：

private class OnTokenAcquired implements AccountManagerCallback<Bundle> {
    @Override
    public void run(AccountManagerFuture<Bundle> result) {
        try {
            final String token = result.getResult().getString(AccountManager.KEY_AUTHTOKEN);
            HttpTransport httpTransport = new NetHttpTransport();
            JacksonFactory jsonFactory = new JacksonFactory();
            Drive.Builder b = new Drive.Builder(httpTransport, jsonFactory, null);
            b.setJsonHttpRequestInitializer(new JsonHttpRequestInitializer() {
                @Override
                public void initialize(JSonHttpRequest request) throws IOException {
                    DriveRequest driveRequest = (DriveRequest) request;
                    driveRequest.setPrettyPrint(true);
                    driveRequest.setKey(CLIENT ID YOU GOT WHEN SETTING UP THE CONSOLE BEFORE YOU STARTED CODING)
                    driveRequest.setOauthToken(token);
                }
            });

            final Drive drive = b.build();

            final com.google.api.services.drive.model.File body = new com.google.api.services.drive.model.File();
            body.setTitle("My Test File");
    body.setDescription("A Test File");
    body.setMimeType("text/plain");

            final FileContent mediaContent = new FileContent("text/plain", an ordinary java.io.File you'd like to upload. Make it using a FileWriter or something, that's really outside the scope of this answer.)
            new Thread(new Runnable() {
                public void run() {
                    try {
                        com.google.api.services.drive.model.File file = drive.files().insert(body, mediaContent).execute();
                        alreadyTriedAgain = false; // Global boolean to make sure you don't repeatedly try too many times when the server is down or your code is faulty... they'll block requests until the next day if you make 10 bad requests, I found.
                    } catch (IOException e) {
                        if (!alreadyTriedAgain) {
                            alreadyTriedAgain = true;
                            AccountManager am = AccountManager.get(activity);
                            am.invalidateAuthToken(am.getAccounts()[0].type, null); // Requires the permissions MANAGE_ACCOUNTS & USE_CREDENTIALS in the Manifest
                            am.getAuthToken (same as before...)
                        } else {
                            // Give up. Crash or log an error or whatever you want.
                        }
                    }
                }
            }).start();
            Intent launch = (Intent)result.getResult().get(AccountManager.KEY_INTENT);
            if (launch != null) {
                startActivityForResult(launch, 3025);
                return; // Not sure why... I wrote it here for some reason. Might not actually be necessary.
            }
        } catch (OperationCanceledException e) {
            // Handle it...
        } catch (AuthenticatorException e) {
            // Handle it...
        } catch (IOException e) {
            // Handle it...
        }
    }
}

ANDROID代码 - 下载

private java.io.File downloadGFileToJFolder(Drive drive, String token, File gFile, java.io.File jFolder) throws IOException {
    if (gFile.getDownloadUrl() != null && gFile.getDownloadUrl().length() > 0 ) {
        if (jFolder == null) {
            jFolder = Environment.getExternalStorageDirectory();
            jFolder.mkdirs();
        }
        try {

            HttpClient client = new DefaultHttpClient();
            HttpGet get = new HttpGet(gFile.getDownloadUrl());
            get.setHeader("Authorization", "Bearer " + token);
            HttpResponse response = client.execute(get);

            InputStream inputStream = response.getEntity().getContent();
            jFolder.mkdirs();
            java.io.File jFile = new java.io.File(jFolder.getAbsolutePath() + "/" + getGFileName(gFile)); // getGFileName() is my own method... it just grabs originalFilename if it exists or title if it doesn't.
            FileOutputStream fileStream = new FileOutputStream(jFile);
            byte buffer[] = new byte[1024];
            int length;
            while ((length=inputStream.read(buffer))>0) {
                fileStream.write(buffer, 0, length);
            }
            fileStream.close();
            inputStream.close();
            return jFile;
        } catch (IOException e) {        
            // Handle IOExceptions here...
            return null;
        }
    } else {
        // Handle the case where the file on Google Drive has no length here.
        return null;
    }
}

您可以使用AsyncTask下载（或复制本地图像），然后进行处理。

在您的活动中创建：

private class PictureAsyncTask extends AsyncTask<Void, Void, String> {
    private Uri mUri;

    public PictureAsyncTask(Uri uri) {
        mUri = uri;
    }

    @Override
    protected String doInBackground(Void... params) {
        InputStream inputStream = null;
        try {
            inputStream = getContentResolver().openInputStream(mUri);
            String path = null; // Path of downloaded image
            // Download image from inputStream
            return path;
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (inputStream != null) {
                try {
                    inputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return null
    }

    @Override
    protected void onPostExecute(String path) {
        if (path == null) {
            // Process image
            // Maybe another AsyncTask or background thread?
        } else {
            // Download failed
        }
    }
}

从onActivityResult调用它：

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    switch (requestCode) {
        case RESULT_LOAD_IMG:
            if (resultCode == RESULT_OK) {
                if (data != null) {
                    Uri uri = data.getData();
                    if (uri != null) {
                        new PictureAsyncTask(uri).execute();
                    } else {
                        // No data
                    }
                } else {
                    // No picture selected?
                }
            }
            break;
    }
}