安卓 申請寫文件權限

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

    private void applyAuth(){
        if(Build.VERSION.SDK_INT >= 23){
            int REQUEST_CODE_CONTANCT = 101;
            String[] permissions = {
                    Manifest.permission.WRITE_EXTERNAL_STORAGE
            };

            for(String str:permissions){
                if(MainActivity.this.checkSelfPermission(str) != PackageManager.PERMISSION_GRANTED){
                    MainActivity.this.requestPermissions(permissions,REQUEST_CODE_CONTANCT);
                    return;
                }
            }
        }
    }

追加寫入

package com.fm.vgather;

import android.os.Environment;
import android.util.Log;

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;

public class FileUtils {
    public static void writeFile(String message , String fileName){
        String path = Environment.getExternalStorageDirectory() + "/BlueV";
        File files = new File(path);
        Date date = new Date();
        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-M-dd HH:mm:ss,EE", Locale.CHINA);
        String formatDate = dateFormat.format(date);

        if(!files.exists()){
            files.mkdirs();
        }

        if(files.exists()){
            try{
                FileWriter fw = new FileWriter(path + File.separator + fileName + ".txt",true);
                fw.write(message + "\n");
                fw.write("\n");
                fw.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}