自学总结了下，发出来，想让大家给我指正一下，是否有理解不到位的

今天面试遇到这么个问题，就是应用在在第一次打开的时候，如果要去初始化加载一些数据，这时候因为某种原因程序退出了，只加载了50%，那下一次怎么保证它完全加载?

按照老师原代码敲出来的依然没有权限依然报错

W/System.err: java.io.FileNotFoundException: /storage/sdcard0/info.text: open failed: EACCES (Permission denied)

得知6.0以上版本需要 重新获取动态权限

试了一下方法

https://blog.csdn.net/wuqingyou_w/article/details/60138807

此方法测试依然报错

又重新试了另一种方法

https://blog.csdn.net/qq_35649072/article/details/105440376

这两个方法依然提示报错

当前源码如下

 package ymbky.example.qqdemotest;

import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;

import android.app.Activity;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.nio.charset.StandardCharsets;

public class SDCardDemoActivity extends Activity implements View.OnClickListener{

    private static final String TAG1 = "SDCardDemoActivity";
    private Button mwriteDataBtn;

//    private static final int REQUEST_EXTERNAL_STORAGE = 1;
//    private static String[] PERMISSIONS_STORAGE = {
//            "android.permission.READ_EXTERNAL_STORAGE",
//            "android.permission.WRITE_EXTERNAL_STORAGE" };
//    public static void verifyStoragePermissions(Activity activity) {
//
//        try {
//            //检测是否有写的权限
//            int permission = ActivityCompat.checkSelfPermission(activity,
//                    "android.permission.WRITE_EXTERNAL_STORAGE");
//            if (permission != PackageManager.PERMISSION_GRANTED) {
//                // 没有写的权限，去申请写的权限，会弹出对话框
//                ActivityCompat.requestPermissions(activity, PERMISSIONS_STORAGE,REQUEST_EXTERNAL_STORAGE);
//            }
//        } catch (Exception e) {
//            e.printStackTrace();
//        }
//    }


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_sdcard_demo);
//        verifyStoragePermissions(this);
        mwriteDataBtn= this.findViewById(R.id.write_data_2_sd_card_btn);
        mwriteDataBtn.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
       if (v==mwriteDataBtn){
           File filePath=new File("/storage/sdcard0");
           File file=new File(filePath,"info.text");
           try {

//               if (!file.exists()){
//               file.createNewFile();
//           }

               FileOutputStream fos=new FileOutputStream(file);
               fos.write(("LLLLLLLL").getBytes(StandardCharsets.UTF_8));
               fos.flush();
               fos.close();
               Log.d(TAG1,"写入成功");
           } catch (Exception e) {
               e.printStackTrace();
           }
       }
    }
}

我把自己添加的全部注释掉了，现在该怎么改才才能获得动态权限读取写入的功能

代码如下，现在能运行 能安装就是在输入账号密码之后，无法春昂见

class MainActivity : AppCompatActivity(),View.OnClickListener{
    private var mAccount: EditText? = null
    private var mPassword: EditText? = null
    private var mlogin: Button? = null
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        initView()
        ininListener()
    }

    private fun ininListener() {
        mlogin!!.setOnClickListener { v -> handlerLoginEvent(v) }
    }

    private fun handlerLoginEvent(v: View) {
        val accountText = mAccount!!.text.toString()
        val passwordText = mPassword!!.text.toString()
        saveUserInfo(accountText, passwordText)
    }

    private fun saveUserInfo(accountText: String, passwordText: String) {
        Log.d(TAG, "保存了用户信息")
        //        File fileDir=this.getFilesDir();
//        Log.d(TAG,"filesDir==="+fileDir.toString());
        var fileDir=this.getFilesDir();
        Log.d(TAG,"+++++"+fileDir)
        try {
            val file = File("/data/user/0/ymbky.example.suizai/files/info.text")
            if (!file.exists()) {
                file.createNewFile()
            }
            val fos = FileOutputStream(file)
            fos.write("$accountText****$passwordText".toByteArray())
            fos.close()
        } catch (e: Exception) {
            e.printStackTrace()
        }
    }

    private fun initView() {
        mAccount = findViewById(R.id.et_account)
        mPassword = findViewById(R.id.et_password)
        mlogin = findViewById(R.id.bt_login)
    }

    companion object {
        private const val TAG = "MainActivity"
    }

    override fun onClick(v: View?) {
        TODO("Not yet implemented")
    }

 现在经过测试可以确定在 

private fun handlerLoginEvent(v: View) {
        val accountText = mAccount!!.text.toString()
        val passwordText = mPassword!!.text.toString()
        saveUserInfo(accountText, passwordText)
    }
这一步能够拿到输入的账号密码，但是写不出来 ，大佬帮忙看一下