您不能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。
要从谷歌驱动器下载图像或文件，您需要一个库
- google-api-services-drive-v2-rev9-1.8.0-beta.jar()
设置控制台
接下来去谷歌控制台
做一个新项目。在服务下，您需要打开两件事：DRIVE API 和 DRIVE SDK！它们是分开的，一个不会自动打开另一个，您必须同时打开！（弄清楚这一点浪费了我至少 20 个小时的时间。）
仍然在控制台上，转到 API 访问。创建一个客户端，使其成为 Android 应用程序。给它你的包 ID。我认为指纹这件事实际上并不重要，因为我很确定我使用了错误的指纹，但无论如何都要尽量做到这一点（谷歌提供了相关说明。）
它将生成一个Client ID。你会需要那个。坚持下去。
ANDROID 代码 - 设置和上传
首先，获取一个身份验证令牌：
AccountManager am = AccountManager.get(activity); am.getAuthToken(am.getAccounts())[0], "oauth2:" + DriveScopes.DRIVE, new Bundle(), true, new OnTokenAcquired(), null);
接下来，需要像这样设置 OnTokenAcquired()：
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;
}
}