Question

我的要求是在活动循环中下载多个图像或使用下载管理器下载AsycTask doinBackground方法（我只需要初始化下载，但即使在应用程序关闭后它仍继续下载图像）并将所有图像存储在SD卡中在我的应用程序文件夹（例如MyAppFolder）中，因为我需要与另一个应用程序共享图像路径并在下载后我需要更改图像的扩展名，以便它在gallery文件夹中不可见。

Answer 1

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {


        String root_sd = Environment.getExternalStorageDirectory().toString();
        // Set the URL to download image 
        String PhotoPictureDownLoadPath= "http://test.com/test.jpg";
        String photoPictureDirectoryPath = root_sd + "/DownloadImages/";
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Call this method in a loop to DOwnLoad Multiple Images.
        new  DownloadImages(MainActivity.this,PhotoPictureDownLoadPath,photoPictureDirectoryPath);
    }
}



// Class to download Images
public class DownloadImages {
    Context myContext;
    String myDownlaodURL;
    String mySdCardSaveImagePath;

    public DownloadImages(Context theContext, String theUrl, String thePath) {
        myContext = theContext;
        myDownlaodURL = theUrl;
        mySdCardSaveImagePath = thePath;

        String PhotoPictureName = getFilename(myDownlaodURL);
        File PhotoPictureSavePath = new File(mySdCardSaveImagePath + "/" + PhotoPictureName);
        if (PhotoPictureSavePath.exists()) {
            return;
        }
        if (!PhotoPictureSavePath.exists()) {
            download();
        }
    }

    public String getFilename(String theFileName) {

        String filename = theFileName.substring(theFileName.lastIndexOf("/") + 1, theFileName.length());
        return filename;
    }

    public void download() {
        Uri Download_Uri = Uri.parse(myDownlaodURL);
        DownloadManager downloadManager = (DownloadManager) myContext.getSystemService(myContext.DOWNLOAD_SERVICE);
        DownloadManager.Request request = new DownloadManager.Request(Download_Uri);

        //Restrict the types of networks over which this download may proceed.
        request.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI | DownloadManager.Request.NETWORK_MOBILE);
        //Set whether this download may proceed over a roaming connection.
        request.setAllowedOverRoaming(true);
        //Set the local destination for the downloaded file to a path within the application's external files directory
        //request.setDestinationInExternalFilesDir(myContext, mySdCardSaveImagePath, split[split.length - 1]);
        //request.setDestinationInExternalPublicDir(Environment.DIRECTORY_PICTURES, split[split.length-1]);

        String[] split = myDownlaodURL.split("/");
        //Set the local destination for the downloaded file to the folder specified by user.
        File destinationFile = new File(mySdCardSaveImagePath, split[split.length - 1]);
        request.setDestinationUri(Uri.fromFile(destinationFile));

        //Set the title of this download, to be displayed in notifications (if enabled).
        request.setTitle(split[split.length - 1]);
        //Set a description of this download, to be displayed in notifications (if enabled)
        request.setDescription(mySdCardSaveImagePath);

        request.setVisibleInDownloadsUi(true);

        //Enqueue a new download and get the reference Id
        long downloadReference = downloadManager.enqueue(request);
    }
}

//change the extension of image after downloading
public class DownloadBroadcastReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        if (DownloadManager.ACTION_DOWNLOAD_COMPLETE.equals(action)) {
            long downloadId = intent.getLongExtra(
                    DownloadManager.EXTRA_DOWNLOAD_ID, 0);

            DownloadManager myDownloadManager = (DownloadManager) context.getSystemService(context.DOWNLOAD_SERVICE);
            Cursor c = myDownloadManager.query(new DownloadManager.Query().setFilterById(downloadId));
            if (c.moveToFirst()) {
                int columnIndex = c
                        .getColumnIndex(DownloadManager.COLUMN_STATUS);
                if (DownloadManager.STATUS_SUCCESSFUL == c
                        .getInt(columnIndex)) {

                    int filenameIndex = c.getColumnIndex(DownloadManager.COLUMN_TITLE);
                    String filename = c.getString(filenameIndex);

                    int filePathIndex = c.getColumnIndex(DownloadManager.COLUMN_DESCRIPTION);
                    String filePath = c.getString(filePathIndex);


                    if (!filename.isEmpty()) {
                        int dotposition = filename.lastIndexOf(".");
                        String filename_Without_Ext = filename.substring(0, dotposition);
                        String Ext = filename.substring(dotposition + 1, filename.length());
                        String newFileName = filename_Without_Ext + ".change" + Ext;
                        boolean success = new File(filePath + "/" + filename).
                                renameTo(new File(filePath + "/" + newFileName));
                        //Log.d("Log", "" + success);
                    }

                }
            }
        }
    }
}

//use  bellow premissions
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
    <uses-permission android:name="android.permission.INTERNET"/>

     <!-- Register Receiver in Manifest-->
     <receiver android:name=".DownloadBroadcastReceiver">
            <intent-filter>
                <action android:name="android.intent.action.DOWNLOAD_COMPLETE"/>
            </intent-filter>
     </receiver>

下载后下载多个图像并更改扩展名

1 个答案: