想列出android 内部存储根目录(内部存储也是sd卡形式)

File path =Environment.getExternalStorageDirectory();

File[] files=path.listFiles();for(int i=0;i

str1+= files[i].getAbsolutePath()+",";

}

textView.setText("bb"+str1);

发现老是提示报错 ，debug 发现eacces，是权限问题

1、先在AndroidManifest.xml 里

还加了

android:allowBackup="true"

android:requestLegacyExternalStorage="true"

发现还没有用，即使在手机权限里加上还不行

2、加上下面代码好了，新版本需要用下面的方式

private final int REQUEST_EXTERNAL_STORAGE = 1;private String[] PERMISSIONS_STORAGE ={

Manifest.permission.READ_EXTERNAL_STORAGE,

Manifest.permission.WRITE_EXTERNAL_STORAGE };public voidverifyStoragePermissions(Activity activity) {//Check if we have write permission

int permission =ActivityCompat.checkSelfPermission(activity,

Manifest.permission.WRITE_EXTERNAL_STORAGE);if (permission !=PackageManager.PERMISSION_GRANTED) {//We don‘t have permission so prompt the user

ActivityCompat.requestPermissions(activity, PERMISSIONS_STORAGE,

REQUEST_EXTERNAL_STORAGE);

}

}

然后在

onCreate 里调用

public class MainActivity extends AppCompatActivity {

@Override

protected void onCreate(Bundle savedInstanceState) {

verifyStoragePermissions(this);

3、后面处理读写文件也ok了

try{

File urlFile= new File(str3+"/sd/test.txt");

Log.e("-----------","111");

InputStreamReader isr= new InputStreamReader(new FileInputStream(urlFile), "UTF-8");

BufferedReader br= newBufferedReader(isr);

Log.e("-----------","112221");

String str= "";

String mimeTypeLine= null;while ((mimeTypeLine = br.readLine()) != null) {

str= str+mimeTypeLine;

}

Log.e("-----------",str);

textView.setText(str);

}catch(Exception e) {

e.printStackTrace();

}

原文：https://www.cnblogs.com/cnchengv/p/14664560.html