我通过@hcpl和@mad的解决方案。hcpl的解决方案很好地支持图库中的本地图像& mad在此基础上提供了一个更好的解决方案-它也有助于加载OI/Astro/Dropbox图像。但在我的应用程序中，虽然在picasa库工作，现在集成在Android画廊，这两个解决方案都失败了。

我进行了一些搜索和分析，最终得出了一个更好和优雅的解决方案，克服了这一限制。感谢Dimitar Darazhanski的博客，在这种情况下，他帮助了我，我修改了一些，使它更容易理解。这是我的解

public class BrowsePicture extends Activity {

//YOU CAN EDIT THIS TO WHATEVER YOU WANT
private static final int SELECT_PICTURE = 1;

private String selectedImagePath;
//ADDED
private String filemanagerstring;

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    ((Button) findViewById(R.id.Button01))
    .setOnClickListener(new OnClickListener() {

        public void onClick(View arg0) {

            // in onCreate or any event where your want the user to
            // select a file
            Intent intent = new Intent();
            intent.setType("image/*");
            intent.setAction(Intent.ACTION_GET_CONTENT);
            startActivityForResult(Intent.createChooser(intent,
                    "Select Picture"), SELECT_PICTURE);
        }
    });
}

public void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (resultCode == RESULT_OK) {
        if (requestCode == SELECT_PICTURE) {
            Uri selectedImageUri = data.getData();
            Log.d("URI VAL", "selectedImageUri = " + selectedImageUri.toString());
            selectedImagePath = getPath(selectedImageUri);

            if(selectedImagePath!=null){         
                // IF LOCAL IMAGE, NO MATTER IF ITS DIRECTLY FROM GALLERY (EXCEPT PICASSA ALBUM),
                // OR OI/ASTRO FILE MANAGER. EVEN DROPBOX IS SUPPORTED BY THIS BECAUSE DROPBOX DOWNLOAD THE IMAGE 
                // IN THIS FORM - file:///storage/emulated/0/Android/data/com.dropbox.android/...
                System.out.println("local image"); 
            }
            else{
                System.out.println("picasa image!");
                loadPicasaImageFromGallery(selectedImageUri);
            }
        }
    }
}


// NEW METHOD FOR PICASA IMAGE LOAD
private void loadPicasaImageFromGallery(final Uri uri) {
    String[] projection = {  MediaColumns.DATA, MediaColumns.DISPLAY_NAME };
    Cursor cursor = getContentResolver().query(uri, projection, null, null, null);
    if(cursor != null) {
        cursor.moveToFirst();

        int columnIndex = cursor.getColumnIndex(MediaColumns.DISPLAY_NAME);
        if (columnIndex != -1) {
            new Thread(new Runnable() {
                // NEW THREAD BECAUSE NETWORK REQUEST WILL BE MADE THAT WILL BE A LONG PROCESS & BLOCK UI
                // IF CALLED IN UI THREAD 
                public void run() {
                    try {
                        Bitmap bitmap = android.provider.MediaStore.Images.Media.getBitmap(getContentResolver(), uri);
                        // THIS IS THE BITMAP IMAGE WE ARE LOOKING FOR.
                    } catch (Exception ex) {
                        ex.printStackTrace();
                    }
                }
            }).start();
        }
    }
    cursor.close();
}


public String getPath(Uri uri) {
    String[] projection = {  MediaColumns.DATA};
    Cursor cursor = getContentResolver().query(uri, projection, null, null, null);
    if(cursor != null) {
        //HERE YOU WILL GET A NULLPOINTER IF CURSOR IS NULL
        //THIS CAN BE, IF YOU USED OI FILE MANAGER FOR PICKING THE MEDIA
        cursor.moveToFirst();
        int columnIndex = cursor.getColumnIndexOrThrow(MediaColumns.DATA);
        String filePath = cursor.getString(columnIndex);
        cursor.close();
        return filePath;
    }
    else 
        return uri.getPath();               // FOR OI/ASTRO/Dropbox etc
}

检查一下，如果有什么问题请告诉我。我已经测试过了，它在每种情况下都很好。

希望这对大家有所帮助。

package com.ImageConvertingDemo;

import java.io.BufferedInputStream;
import java.io.FileInputStream;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.util.Log;
import android.widget.EditText;
import android.widget.ImageView;

public class MyActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        EditText tv = (EditText)findViewById(R.id.EditText01);
        ImageView iv = (ImageView)findViewById(R.id.ImageView01);
        FileInputStream in;
        BufferedInputStream buf;
            try 
            {
                in = new FileInputStream("/sdcard/smooth.png");
                buf = new BufferedInputStream(in,1070);
                System.out.println("1.................."+buf);
                byte[] bMapArray= new byte[buf.available()];
                tv.setText(bMapArray.toString());
                buf.read(bMapArray);
                Bitmap bMap = BitmapFactory.decodeByteArray(bMapArray, 0, bMapArray.length);

                /*for (int i = 0; i < bMapArray.length; i++) 
                {
                System.out.print("bytearray"+bMapArray[i]);
                }*/
                iv.setImageBitmap(bMap);
                //tv.setText(bMapArray.toString());
                //tv.setText(buf.toString());
                if (in != null) 
                {
                    in.close();
                }
                if (buf != null) 
                {
                    buf.close();
                }

            } 
            catch (Exception e) 
            {
                Log.e("Error reading file", e.toString());
            }
    }
}

检索特定类型的文件

这个示例将获得图像的副本。

static final int REQUEST_IMAGE_GET = 1;

public void selectImage() {
    Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
    intent.setType("image/*");
    if (intent.resolveActivity(getPackageManager()) != null) {
        startActivityForResult(intent, REQUEST_IMAGE_GET);
    }
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == REQUEST_IMAGE_GET && resultCode == RESULT_OK) {
        Bitmap thumbnail = data.getParcelable("data");
        Uri fullPhotoUri = data.getData();
        // Do work with photo saved at fullPhotoUri
        ...
    }
}

打开特定类型的文件

在4.4或更高版本上运行时，您请求打开由另一个应用程序管理的文件

static final int REQUEST_IMAGE_OPEN = 1;

public void selectImage() {
    Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
    intent.setType("image/*");
    intent.addCategory(Intent.CATEGORY_OPENABLE);
    // Only the system receives the ACTION_OPEN_DOCUMENT, so no need to test.
    startActivityForResult(intent, REQUEST_IMAGE_OPEN);
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == REQUEST_IMAGE_OPEN && resultCode == RESULT_OK) {
        Uri fullPhotoUri = data.getData();
        // Do work with full size photo saved at fullPhotoUri
        ...
    }
}

原始来源

在上面代码的基础上，我反映了如下代码，可能它更适合:

public String getPath(Uri uri) {
    String selectedImagePath;
    //1:MEDIA GALLERY --- query from MediaStore.Images.Media.DATA
    String[] projection = { MediaStore.Images.Media.DATA };
    Cursor cursor = managedQuery(uri, projection, null, null, null);
    if(cursor != null){
        int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
        cursor.moveToFirst();
        selectedImagePath = cursor.getString(column_index);
    }else{
        selectedImagePath = null;
    }

    if(selectedImagePath == null){
        //2:OI FILE Manager --- call method: uri.getPath()
        selectedImagePath = uri.getPath();
    }
    return selectedImagePath;
}

这是我的例子，可能不完全是你的情况。

假设你从你的API提供者获得base64格式，给它一个文件名和文件扩展名，将它保存到文件系统中的某个位置。

public static void shownInBuiltInGallery(final Context ctx, String strBase64Image, final String strFileName, final String strFileExtension){

new AsyncTask<String, String, File>() {
    @Override
    protected File doInBackground(String... strBase64Image) {

        Bitmap bmpImage = convertBase64StringToBitmap(strBase64Image[0], Base64.NO_WRAP);

        if(bmpImage == null) {
            cancel(true);
            return null;
        }

        byte[] byImage = null;

        if(strFileExtension.compareToIgnoreCase(FILE_EXTENSION_JPG) == 0) {
            byImage = convertToJpgByte(bmpImage); // convert bitmap to binary for latter use
        } else if(strFileExtension.compareToIgnoreCase(FILE_EXTENSION_PNG) == 0){
            byImage = convertToPngByte(bmpImage); // convert bitmap to binary for latter use
        } else if(strFileExtension.compareToIgnoreCase(FILE_EXTENSION_BMP) == 0){
            byImage = convertToBmpByte(bmpImage); // convert bitmap to binary for latter use
        } else {
            cancel(true);
            return null;
        }

        if(byImage == null) {
            cancel(true);
            return null;
        }

        File imageFolder = ctx.getExternalCacheDir();

        if(imageFolder.exists() == false){
            if(imageFolder.mkdirs() == false){
                cancel(true);
                return null;
            }
        }

        File imageFile = null;

        try {
            imageFile = File.createTempFile(strFileName, strFileExtension, imageFolder);
        } catch (IOException e){
            e.printStackTrace();
        }

        if(imageFile == null){
            cancel(true);
            return null;
        }

        if (imageFile.exists() == true) {
            if(imageFile.delete() == false){
                cancel(true);
                return null;
            }
        }

        FileOutputStream fos = null;

        try {
            fos = new FileOutputStream(imageFile.getPath());
            fos.write(byImage);
            fos.flush();
            fos.close();
        } catch (java.io.IOException e) {
            e.printStackTrace();
        } finally {
            fos = null;
        }

        return imageFile;
    }

    @Override
    protected void onPostExecute(File file) {
        super.onPostExecute(file);

            String strAuthority = ctx.getPackageName() + ".provider";
            Uri uriImage = FileProvider.getUriForFile(ctx, strAuthority, file);

            Intent intent = new Intent(Intent.ACTION_VIEW);
            intent.setDataAndType(uriImage, "image/*");
            intent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
            ctx.startActivity(intent);

    }
}.execute(strBase64Image);}

不要忘记在AndroidManifest.xml中首先设置一个适当的文件提供程序

        <provider
        android:name="android.support.v4.content.FileProvider"
        android:authorities="${applicationId}.provider"
        android:exported="false"
        android:grantUriPermissions="true">

        <meta-data
            android:name="android.support.FILE_PROVIDER_PATHS"
            android:resource="@xml/file_paths"/>
    </provider>

文件路径是XML在…/res/ XML /file_path.xml

<?xml version="1.0" encoding="utf-8"?>

<external-files-path name="external_files" path="Accessory"/>

<external-path name="ex_Download" path="Download/" />
<external-path name="ex_Pictures" path="Pictures/" />

<external-files-path name="my_Download" path="Download/" />
<external-files-path name="my_Pictures" path="Pictures/" />
<external-cache-path name="my_cache" path="." />

<files-path name="private_Download" path="Download/" />
<files-path name="private_Pictures" path="Pictures/" />
<cache-path name="private_cache" path="." />

长话短说，首先准备好文件提供程序，将已知且可访问的图片源的Uri传递给Intent，否则，将图片保存在所需的位置，然后将位置(作为Uri)传递给Intent。

hcpl的方法在kitkat之前工作得很好，但不能与DocumentsProvider API一起工作。为此，只需简单地遵循官方的Android文档提供者教程:https://developer.android.com/guide/topics/providers/document-provider.html ->打开一个文档，位图部分。

简单地，我使用了hcpl的代码并扩展了它:如果图像的检索路径的文件抛出异常，我调用这个函数:

private Bitmap getBitmapFromUri(Uri uri) throws IOException {
        ParcelFileDescriptor parcelFileDescriptor =
             getContentResolver().openFileDescriptor(uri, "r");
        FileDescriptor fileDescriptor = parcelFileDescriptor.getFileDescriptor();
        Bitmap image = BitmapFactory.decodeFileDescriptor(fileDescriptor);
        parcelFileDescriptor.close();
        return image;
}

在Nexus 5上测试。