我正在使用Google Drive Api。我想从Google云端硬盘下载图片。 下面是正在运行的代码，但是在循环结束时调用files.open（）。假设计数为3，循环将首先完成循环，之后将调用files.open（）3次。因此，我无法在我的模型类中设置数据。它只需要最后一个值。 （编者）
if (getGoogleApiClient() != null && getGoogleApiClient().isConnected()) {
try {
final DriveFolder pFldr = Drive.DriveApi.getRootFolder(getGoogleApiClient());
pFldr.listChildren(getGoogleApiClient()).setResultCallback(new ResultCallback<DriveApi.MetadataBufferResult>() {
@Override
public void onResult(DriveApi.MetadataBufferResult metadataBufferResult) {
int count = metadataBufferResult.getMetadataBuffer().getCount();
Log.e("COUNT---", count + "");
MetadataBuffer buffer = metadataBufferResult.getMetadataBuffer();
if (count > 0) {
for (int i = 0; i < count; i++) {
if (buffer.get(i).getMimeType().equals("image/jpeg")) {
Log.e("Images avaialbe - ", "" + buffer.get(i).getTitle());
DriveId id = buffer.get(i).getDriveId();
DriveFile files = Drive.DriveApi.getFile(getGoogleApiClient(), id);
driveModel.setTitle(buffer.get(i).getTitle());
files.open(getGoogleApiClient(), DriveFile.MODE_READ_ONLY, null).setResultCallback(saveImageCallback);
}
if (buffer.get(i).getMimeType().equals("application/x-sqlite3")) {
DriveId id = buffer.get(i).getDriveId();
DriveFile files = Drive.DriveApi.getFile(getGoogleApiClient(), id);
files.open(getGoogleApiClient(), DriveFile.MODE_READ_ONLY, null).setResultCallback(saveDataBaseCallback);
}
}
buffer.release();
showMessage("Success");
} else {
showMessage("No Back Up available.");
}
}
});
} finally {
}
}
ResultCallback<DriveApi.DriveContentsResult> saveImageCallback = new ResultCallback<DriveApi.DriveContentsResult>() {
@Override
public void onResult(DriveApi.DriveContentsResult driveContentsResult) {
DriveContents cont = driveContentsResult.getDriveContents();
InputStream inputStream = cont.getInputStream();
try {
saveFiles(inputStream, driveModel.getTitle(), false);
cont.discard(getGoogleApiClient());
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
答案 0 :(得分：1)
试试这个：
1.）更改为ArrayList<DriveModel> driveFileList;
2.）
pFldr.listChildren
(getGoogleApiClient())
.setResultCallback(new ResultCallback<DriveApi.MetadataBufferResult>() {
@Override
public void onResult(DriveApi.MetadataBufferResult metadataBufferResult) {
int count = metadataBufferResult.getMetadataBuffer().getCount();
Log.e("COUNT---", count + "");
Log.e("CHECk" , "Calling callback read from googledrive");
MetadataBuffer buffer = metadataBufferResult.getMetadataBuffer();
if (count > 0) {
for (int i = 0; i < count; i++) {
final int finalI = i;
Log.e("CHECk" , "reading file " + buffer.get(i).getTitle());
Log.e("Files avaialbe - ", "" + buffer.get(i).getTitle());
driveModel=new DriveModel();
DriveId id = buffer.get(i).getDriveId();
DriveFile files = Drive.DriveApi.getFile(getGoogleApiClient(), id);
if (buffer.get(i).getMimeType().equals("image/jpeg") ||
buffer.get(i).getMimeType().equals("image/png")) {
driveModel.setTitle(buffer.get(i).getTitle());
Log.e("Images avaialbe - ", "" + buffer.get(i).getTitle());
// driveModel.setTitle(buffer.get(i).getTitle());
files.open(getGoogleApiClient(), DriveFile.MODE_READ_ONLY, null)
.setResultCallback(new ResultCallback<DriveApi.DriveContentsResult>() {
@Override
public void onResult(@NonNull DriveApi.DriveContentsResult driveContentsResult) {
saveData(driveContentsResult, finalI);
}
});
driveFileList.add(driveModel);
}
if (buffer.get(i).getMimeType().equals("application/x-sqlite3")) {
files.open(getGoogleApiClient(), DriveFile.MODE_READ_ONLY, null)
.setResultCallback(new ResultCallback<DriveApi.DriveContentsResult>() {
@Override
public void onResult(@NonNull DriveApi.DriveContentsResult driveContentsResult) {
saveData(driveContentsResult, finalI);
}
});
}
}
buffer.release();
showMessage("Success");
} else {
showMessage("No Back Up available.");
}
}
}
);
3。）创建方法：
private void saveData(DriveApi.DriveContentsResult driveContentsResult, int i) {
Log.e("CHECk" , "Calling callback " + driveContentsResult.getDriveContents().getDriveId().encodeToString() );
DriveContents cont = driveContentsResult.getDriveContents();
Log.e("File name :" , "File : " + driveFileList.get(i).getTitle());
//Put your code here
InputStream inputStream = cont.getInputStream();
try {
saveFiles(inputStream, true);
cont.discard(getGoogleApiClient());
} catch (IOException e) {
e.printStackTrace();
}
}