從 Uri 創建文件

Question

我正在嘗試將圖像上傳到 php，為此我需要將文件發送到服務器。 所以我試圖從數據參數創建一個文件。

但我收到此錯誤Cannot resolve constructor File

這是我的代碼：

 protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (resultCode == RESULT_OK) {
            // Get the url from data
            Uri selectedImageUri = data.getData();
            if (null != selectedImageUri) {
                // File
                File imageFilePath = new File(selectedImageUri);

Answer 1

合適的方法是getContentResolver().openInputStream(uri_of_your_file); 並使用FileOutputStream到您想要的路徑，然后使用該文件。

來自Commonsware的回答

您可以使用 ContentResolver 和 openInputStream() 來獲取 Uri 表示的內容的 InputStream。 您可以在您控制的某個文件上創建 FileOutputStream。 而且，您可以使用 Java I/O 從 InputStream 復制到 OutputStream，在您控制的文件中制作您自己的內容副本。

這樣做的示例代碼，

InputStream in =  getContentResolver().openInputStream("your_uri_here");
OutputStream out = new FileOutputStream(new File("your_file_here"));
        byte[] buf = new byte[1024];
        int len;
        while((len=in.read(buf))>0){
            out.write(buf,0,len);
        }
        out.close();
        in.close();

Answer 2

@GeekDroid 的回答是正確的，但我想我會提供更多信息來幫助澄清。

我還創建了一個庫，當從MediaStore選擇File時，它將從Uri返回文件路徑。

---

我創建了一個類，它將在您的應用程序目錄中復制/創建一個新文件。 這是在后台線程上完成的，因為它應該這樣做。

我還創建了一個回調接口來獲取“狀態”並顯示一個ProgressBar

這是界面（您可以將名稱和回調更改為任何內容）：

interface CallBackTask {
    void onCopyPreExecute();
    void onCopyProgressUpdate(int progress);
    void onCopyPostExecute(String path, boolean wasSuccessful, String reason);
}

這是復制文件的類：

public class CopyFileAsyncTask extends AsyncTask<Uri, Integer, String> {
    private Uri mUri;
    private CallBackTask callback;
    private WeakReference<Context> mContext;
    private String pathPlusName;
    private File folder;
    private Cursor returnCursor;
    private InputStream is = null;
    private String errorReason = "";

    DownloadAsyncTask(Uri uri, Context context, CallBackTask callback) {
        this.mUri = uri;
        mContext = new WeakReference<>(context);
        this.callback = callback;
    }

    @Override
    protected void onPreExecute() {
        callback.onCopyPreExecute();
        Context context = mContext.get();
        if (context != null) {
            folder = context.getExternalFilesDir("Temp");
            returnCursor = context.getContentResolver().query(mUri, null, null, null, null);
            try {
                is = context.getContentResolver().openInputStream(mUri);
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            }
        }
    }

    @Override
    protected void onProgressUpdate(Integer... values) {
        super.onProgressUpdate(values);
        int post = values[0];
        callback.onCopyProgressUpdate(post);
    }

    @Override
    protected String doInBackground(Uri... params) {
        File file = null;
        int size = -1;

        try {
            try {
                if (returnCursor != null && returnCursor.moveToFirst()){
                    if (mUri.getScheme() != null)
                    if (mUri.getScheme().equals("content")) {
                        int sizeIndex = returnCursor.getColumnIndex(OpenableColumns.SIZE);
                        size = (int) returnCursor.getLong(sizeIndex);
                    }else if (mUri.getScheme().equals("file")) {
                        File ff = new File(mUri.getPath());
                        size = (int) ff.length();
                    }
                }
            }
            finally {
                if (returnCursor != null)
                returnCursor.close();
            }

            pathPlusName = folder + "/" + getFileName(mUri, mContext.get());
            file = new File(folder + "/" + getFileName(mUri, mContext.get()));

            BufferedInputStream bis = new BufferedInputStream(is);
            FileOutputStream fos = new FileOutputStream(file);


            byte[] data = new byte[1024];
            long total = 0;
            int count;
            while ((count = bis.read(data)) != -1) {
                if (!isCancelled()) {
                    total += count;
                    if (size != -1) {
                        publishProgress((int) ((total * 100) / size));
                    }
                    fos.write(data, 0, count);
                }
            }
            fos.flush();
            fos.close();

        } catch (IOException e) {
            errorReason = e.getMessage();
        }

        return file.getAbsolutePath();

    }

    private String getFileName(Uri uri, Context context) {
        String result = null;
        if (uri.getScheme() != null) {
            if (uri.getScheme().equals("content")) {
                Cursor cursor = context.getContentResolver().query(uri, null, null, null, null);
                if (cursor != null && cursor.moveToFirst()) {
                    result = cursor.getString(cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME));
                }
                if (cursor != null) {
                    cursor.close();
                }
            }
        }
        if (result == null) {
            result = uri.getPath();
            assert result != null;
            int cut = result.lastIndexOf('/');
            if (cut != -1) {
                result = result.substring(cut + 1);
            }
        }
        return result;
    }

    protected void onPostExecute(String result) {
        if(result == null){
            callback.onCopyPostExecute(pathPlusName, false, errorReason);
        }else {
            callback.onCopyPostExecute(pathPlusName, true, "");
        }
    }
}

在您的Activity中，您應該執行以下操作：

import android.annotation.SuppressLint;
import android.app.AlertDialog;
import android.net.Uri;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.ContextThemeWrapper;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;

public class ExampleActivity extends AppCompatActivity implements CallBackTask{
    Button someBtn;
    Uri someUri = .... //This is just an example, you should provide your own Uri

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_example);

        someBtn = findViewById(R.id.someBtn);

        someBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                CopyFileAsyncTask asyntask = new CopyFileAsyncTask(someUri, ExampleActivity.this, ExampleActivity.this);
                asyntask.execute();
            }
        });

    }
    
    ProgressBar mProgressBar;
    TextView percentText;
    private AlertDialog mdialog;

    @Override
    public void onCopyPreExecute() {
        final AlertDialog.Builder mPro = new AlertDialog.Builder(new ContextThemeWrapper(this, R.style.myDialog));
        @SuppressLint("InflateParams") final View mPView = LayoutInflater.from(this).inflate(R.layout.dailog_layout, null);
        percentText = mPView.findViewById(R.id.percentText);

        mProgressBar = mPView.findViewById(R.id.mProgressBar);
        mProgressBar.setMax(100);
        mPro.setView(mPView);
        mdialog = mPro.create();
        mdialog.show();
    }

    @Override
    public void onCopyProgressUpdate(int progress) {
        String progressPlusPercent = progress + "%";
        percentText.setText(progressPlusPercent);
        mProgressBar.setProgress(progress);
    }

    @Override
    public void onCopyPostExecute(String path, boolean wasSuccessful, String reason) {
        if (mdialog != null && mdialog.isShowing()) {
            mdialog.cancel();
        }

        if (wasSuccessful){
            Toast.makeText(this, "File was created at - "+path, Toast.LENGTH_SHORT).show();
        }else{
            Toast.makeText(this, "Error - "+reason, Toast.LENGTH_SHORT).show();
        }
        
    }
}

您可以隨時取消文件的復制，方法是調用：

if (asyntask!=null){
    asyntask.cancel(true);
}

---

如果您想完全按照我的做法實現它並在復制文件時顯示ProgressBar ，那么這里是我的對話框的布局和樣式：

R.style.myDialog ：

<resources>
    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
    </style>

    <style name="myDialog" parent="Theme.AppCompat.Dialog.Alert">
        <item name="android:windowNoTitle">true</item>
        <item name="android:background">#fff</item>
        <item name="android:windowBackground">@null</item>
        <item name="android:windowFrame">@null</item>
        <item name="android:windowIsFloating">true</item>
        <item name="android:backgroundDimEnabled">true</item>
    </style>

</resources>

R.layout.dailog_layout ：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <RelativeLayout
        android:id="@+id/loadContent"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:padding="20dp">

        <RelativeLayout
            android:id="@+id/dotRel"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <TextView
                android:id="@+id/percentText"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerHorizontal="true"
                android:layout_marginBottom="15dp"
                android:text="0 %"
                android:textColor="@android:color/black"
                android:textSize="25sp" />

            <ProgressBar
                android:id="@+id/mProgressBar"
                style="@android:style/Widget.ProgressBar.Horizontal"
                android:layout_width="match_parent"
                android:layout_height="5dp"
                android:layout_below="@+id/percentText"
                android:progressDrawable="@drawable/progressbar" />

        </RelativeLayout>

    </RelativeLayout>

</RelativeLayout>

這是復制文件時的對話框：

---

結論：

使用上述內容，您的文件將被復制到/storage/emulated/0/Android/data/yourPackageName/files/Temp/YourFile.jpg 。 在復制文件時，將顯示一個進度對話框，以百分比表示進度（這對於復制大文件很有用）。 如果復制文件時出錯，原因將在onCopyPostExecute中提供

這將適用於文件和內容 Uri。

Answer 3

你可以試試這個；

try {
                Uri uri = data.getData();
                String selectedFilePath = FilePath.getPath(getActivity(), uri);
                final File file = new File(selectedFilePath);

                new UploadFileToServer().execute(file);
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }

並像這樣定義FilePath類；

import android.content.ContentUris;
import android.content.Context;
 import android.database.Cursor;
  import android.net.Uri;
import android.os.Build;
import android.os.Environment;
import android.provider.DocumentsContract;
 import android.provider.MediaStore;

 public class FilePath {

/**
 * Method for return file path of Gallery image/ Document / Video / Audio
 *
 * @param context
 * @param uri
 * @return path of the selected image file from gallery
 */
public static String getPath(final Context context, final Uri uri) {

    // check here to KITKAT or new version
    final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;

    // DocumentProvider
    if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) {

        // ExternalStorageProvider
        if (isExternalStorageDocument(uri)) {
            final String docId = DocumentsContract.getDocumentId(uri);
            final String[] split = docId.split(":");
            final String type = split[0];

            if ("primary".equalsIgnoreCase(type)) {
                return Environment.getExternalStorageDirectory() + "/"
                        + split[1];
            }
        }
        // DownloadsProvider
        else if (isDownloadsDocument(uri)) {

            final String id = DocumentsContract.getDocumentId(uri);
            final Uri contentUri = ContentUris.withAppendedId(
                    Uri.parse("content://downloads/public_downloads"),
                    Long.valueOf(id));

            return getDataColumn(context, contentUri, null, null);
        }
        // MediaProvider
        else if (isMediaDocument(uri)) {
            final String docId = DocumentsContract.getDocumentId(uri);
            final String[] split = docId.split(":");
            final String type = split[0];

            Uri contentUri = null;
            if ("image".equals(type)) {
                contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
            } else if ("video".equals(type)) {
                contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
            } else if ("audio".equals(type)) {
                contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
            }

            final String selection = "_id=?";
            final String[] selectionArgs = new String[] { split[1] };

            return getDataColumn(context, contentUri, selection,
                    selectionArgs);
        }
    }
    // MediaStore (and general)
    else if ("content".equalsIgnoreCase(uri.getScheme())) {

        // Return the remote address
        if (isGooglePhotosUri(uri))
            return uri.getLastPathSegment();

        return getDataColumn(context, uri, null, null);
    }
    // File
    else if ("file".equalsIgnoreCase(uri.getScheme())) {
        return uri.getPath();
    }

    return null;
}

/**
 * Get the value of the data column for this Uri. This is useful for
 * MediaStore Uris, and other file-based ContentProviders.
 *
 * @param context
 *            The context.
 * @param uri
 *            The Uri to query.
 * @param selection
 *            (Optional) Filter used in the query.
 * @param selectionArgs
 *            (Optional) Selection arguments used in the query.
 * @return The value of the _data column, which is typically a file path.
 */
public static String getDataColumn(Context context, Uri uri,
                                   String selection, String[] selectionArgs) {

    Cursor cursor = null;
    final String column = "_data";
    final String[] projection = { column };

    try {
        cursor = context.getContentResolver().query(uri, projection,
                selection, selectionArgs, null);
        if (cursor != null && cursor.moveToFirst()) {
            final int index = cursor.getColumnIndexOrThrow(column);
            return cursor.getString(index);
        }
    } finally {
        if (cursor != null)
            cursor.close();
    }
    return null;
}

/**
 * @param uri
 *            The Uri to check.
 * @return Whether the Uri authority is ExternalStorageProvider.
 */
public static boolean isExternalStorageDocument(Uri uri) {
    return "com.android.externalstorage.documents".equals(uri
            .getAuthority());
}

/**
 * @param uri
 *            The Uri to check.
 * @return Whether the Uri authority is DownloadsProvider.
 */
public static boolean isDownloadsDocument(Uri uri) {
    return "com.android.providers.downloads.documents".equals(uri
            .getAuthority());
}

/**
 * @param uri
 *            The Uri to check.
 * @return Whether the Uri authority is MediaProvider.
 */
public static boolean isMediaDocument(Uri uri) {
    return "com.android.providers.media.documents".equals(uri
            .getAuthority());
}

/**
 * @param uri
 *            The Uri to check.
 * @return Whether the Uri authority is Google Photos.
 */
public static boolean isGooglePhotosUri(Uri uri) {
    return "com.google.android.apps.photos.content".equals(uri
            .getAuthority());
}
}

Answer 4

一條線解決您的問題

File imageFile = new File(selectedImageUri.getPath());

你錯過了

.getPath()

Answer 5

您可以使用此功能從新 android 和舊版本的 uri 中獲取文件：

fun getFileFromUri(context: Context, uri: Uri?): File? {
    uri ?: return null
    uri.path ?: return null

    var newUriString = uri.toString()
    newUriString = newUriString.replace(
        "content://com.android.providers.downloads.documents/",
        "content://com.android.providers.media.documents/"
    )
    newUriString = newUriString.replace(
        "/msf%3A", "/image%3A"
    )
    val newUri = Uri.parse(newUriString)

    var realPath = String()
    val databaseUri: Uri
    val selection: String?
    val selectionArgs: Array<String>?
    if (newUri.path?.contains("/document/image:") == true) {
        databaseUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI
        selection = "_id=?"
        selectionArgs = arrayOf(DocumentsContract.getDocumentId(newUri).split(":")[1])
    } else {
        databaseUri = newUri
        selection = null
        selectionArgs = null
    }
    try {
        val column = "_data"
        val projection = arrayOf(column)
        val cursor = context.contentResolver.query(
            databaseUri,
            projection,
            selection,
            selectionArgs,
            null
        )
        cursor?.let {
            if (it.moveToFirst()) {
                val columnIndex = cursor.getColumnIndexOrThrow(column)
                realPath = cursor.getString(columnIndex)
            }
            cursor.close()
        }
    } catch (e: Exception) {
        Log.i("GetFileUri Exception:", e.message ?: "")
    }
    val path = realPath.ifEmpty {
        when {
            newUri.path?.contains("/document/raw:") == true -> newUri.path?.replace(
                "/document/raw:",
                ""
            )
            newUri.path?.contains("/document/primary:") == true -> newUri.path?.replace(
                "/document/primary:",
                "/storage/emulated/0/"
            )
            else -> return null
        }
    }
    return if (path.isNullOrEmpty()) null else File(path)
}

Answer 6

如何使用android Uri創建文件

從android.net.Uri創建java.io.File似乎很困難，因為沒有直接的方法可以將android.net.Uri轉換為java.net.URI 。 但是如果你有ApplicationContext你可以很容易地做到這一點。

以下是如何從片段類中執行此操作。

fun createFile(uri: Uri) {
    try {
requireContext().applicationContext.contentResolver.openFileDescriptor(uri, "w")?.use { fd ->
        FileOutputStream(fd).use { fos ->

            // do your job on the FileOutputStream
            // also use background thread

            fos.close()
        }
    }
  } catch (e: Exception) {

  }
}

注意：文件操作會拋出多個異常，請謹慎處理。 並且還在工作線程中進行文件操作。