Android如何正确使用Environment.getExternalStorageDirectory（）

Question

Android如何使用Environment.getExternalStorageDirectory（）

如何使用Environment.getExternalStorageDirectory（）从SD卡读取/写入图像？ 还是有更好的方法呢？

我确实使用源代码下载并保存了图像：

    try {

        URL url = new URL(urlBaseImagem + icone);
        URLConnection conection = url.openConnection();
        conection.connect();
        // this will be useful so that you can show a tipical 0-100% progress bar
        int lenghtOfFile = conection.getContentLength();

        //
        // download the file
        InputStream input = new BufferedInputStream(url.openStream(), 8192);

        // Output stream                
        //File sdCard = Environment.getExternalStoragePublicDirectory(DOWNLOAD_SERVICE);
        File sdCard = Environment.getExternalStorageDirectory();

        File directory = new File(sdCard.getAbsolutePath() + "/cardapioweb/rest/");

        if(directory.exists() == false){
            directory.mkdirs();
        }
        File outputFile = new File(directory, icone);

        OutputStream output = new FileOutputStream(outputFile);

        byte data[] = new byte[1024];

        long total = 0;

        while ((count = input.read(data)) != -1) {
            total += count;
            // publishing the progress....
            // After this onProgressUpdate will be called
            //publishProgress(""+(int)((total*100)/lenghtOfFile));

            // writing data to file
            output.write(data, 0, count);
        }

        // flushing output
        output.flush();

        // closing streams
        output.close();
        input.close();

        Log.w("CardapioWeb:" , "Imagem " + outputFile.toString() + " salva no sdcard");


    } catch (Exception e) {
        Log.e("Error: ", e.getMessage());
    }

我确实使用源来加载e显示图像：

File arq = new File(this.sdCard.getAbsolutePath() + "/cardapioweb/rest/" + filialDataCollection.get(position).get(KEY_ICONE));

//verifica se a imagem foi baixada com sucesso
if(arq.exists() == true){
        //deve exibir a imagem do sdcard
        File outputFile1 = new File(this.sdCard.getAbsolutePath() + "/cardapioweb/rest/", filialDataCollection.get(position).get(KEY_ICONE));
        Drawable imagem = Drawable.createFromPath(outputFile1.toString());
        holder.tvWeatherImage.setImageDrawable(imagem);
 }

上面的代码在带有Eclipse的模拟器（Android虚拟设备）上可以正常工作！ 但是，当我生成apk并安装在我的Galaxy S4上时，该应用无法读取图像（不会产生错误）。 只是不显示图像。 有什么事吗

Answer 1

在您的代码中添加日志以查看

outputFile1.toString();

实际指向的是您所期望的吗？

就个人而言，我将使用outputFile1.getAbsolutePath（）;。 不是下面的行：

Drawable imagem = Drawable.createFromPath(outputFile1.toString());