Android在外部存储上写入

Question

Bitmap bm = BitmapFactory.decodeResource( getResources(), R.drawable.paco);

        File file = new File( Environment.getExternalStorageDirectory(), "paco.png");
        FileOutputStream outStream = null;

        try {
        FileOutputStream out = new FileOutputStream(file);
        bm.compress(Bitmap.CompressFormat.PNG, 90, out);
        out.flush();
        out.close();
            Log.d("XXXXX","voy a cerrar");
        } catch (Exception e) {
           Log.e("XXXXX","eeeee", e);
        }

我的舱单中有权限条目：

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.usuari.myapplication3">

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

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

...

编辑：我正在使用sdk 23

Answer 1

首先，检查您的存储是否准备就绪：

if (Environment.getExternalStorageState(file) != Environment.MEDIA_MOUNTED) {
    // your storage is not ready for work, do something with this
}

其次，就我所记得的，从Kit-Kat开始，你不能写到外部存储的根。只允许写入存储中特定于应用程序的文件夹。若要获取此文件夹，请使用

Environment.getExternalStoragePublicDirectory(directoryType);

关于directoryType，检查方法的文档，您可能想使用environment.directory_pictures。