Android 将位图保存到SD卡

我有一个位图图像，我必须存储在SD卡的文件夹中，我的代码如下所示。它会按预期创建文件夹和文件，但图像不会存储到文件中，它仍然是一个空文件。。。谁能告诉我怎么了

Bitmap merged = Bitmap.createBitmap(mDragLayer.getChildAt(0).getWidth(), mDragLayer.getChildAt(0).getHeight(), Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(merged);

// save to folder in sd card
try {
    File imagesFolder = new File(Environment.getExternalStorageDirectory(), "folder");
    if(!imagesFolder.exists())
        imagesFolder.mkdirs();
    int imageNum;
    if(imagesFolder.list()==null)
        imageNum = 1;
    else
        imageNum = imagesFolder.list().length + 1;

    String fileName = "file_" + String.valueOf(imageNum) + ".jpg";
    File output = new File(imagesFolder, fileName);
    while(output.exists()){
        imageNum++;
        fileName = "file_" + String.valueOf(imageNum) + ".jpg";
        output = new File(imagesFolder, fileName);
    }

    OutputStream fOut = new FileOutputStream(output);
    merged.compress(Bitmap.CompressFormat.JPEG, 100, fOut);
    fOut.flush();
    fOut.close();

    Toast.makeText(getApplicationContext(), "Saved", Toast.LENGTH_SHORT).show();

   } catch (FileNotFoundException e) {
    e.printStackTrace();
   } catch (IOException e) {
    e.printStackTrace();
   }
}

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首先向AndroidManifest.xml添加权限

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission>

已更新

           String strMyImagePath = f.getAbsolutePath();
             FileOutputStream fos = null;
             try {
                 fos = new FileOutputStream(f);
                 bitmap.compress(Bitmap.CompressFormat.PNG,70, fos);

                 fos.flush();
                 fos.close();
              //   MediaStore.Images.Media.insertImage(getContentResolver(), b, "Screen", "screen");
             }catch (FileNotFoundException e) {

                 e.printStackTrace();
             } catch (Exception e) {

                 e.printStackTrace();
             }

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你只需要一个位图

您必须传递一个路径来存储图像

Bitmap b = pagesView.getDrawingCache();
b.compress(CompressFormat.JPEG, 100, new FileOutputStream(Environment.getExternalStorageDirectory() + "/NameOfFile.jpg"));

您必须在清单文件中添加权限

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不要让复杂的代码变得困难。它非常简单，请尝试下面的代码

在sd卡中创建第一个目录：

public static String strpath =  android.os.Environment.getExternalStorageDirectory().toString();
public static String dirName = "DIR_NAME";

File makeDirectory = new File(strpath+"/"+dirName);
makeDirectory.mkdir();

然后您应该创建两个字符串变量，如下所示：

String filename =  "yourImageName".jpg";
String dirpath =strpath + "/"+dirName + "/";

使文件变为变量：

File storagePath =  new File(dirpath);
File myImage = new File(storagePath, filename);
outStream = new FileOutputStream(myImage);  
outStream.write(data);
outStream.close();

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希望这可能对您有所帮助。

我应该将实际位图放在哪里？

File storagePath =  new File(dirpath);
File myImage = new File(storagePath, filename);
outStream = new FileOutputStream(myImage);  
outStream.write(data);
outStream.close();