一、Android存储简介

Android系统分为内部存储和外部存储
从Android6.0开始不断在更新存储权限

外部存储路径的开头：storage/emulated/0
内部存储文件路径的开头：/data/user/0/应用的包名（packageName）
在设备上对应的目录为/data/date/应用的包名（packageName）



系统的公共存储文件夹

二、存储文件路径

TestActivity.kt代码

package example.demo.kotlin

import android.os.Bundle
import android.os.Environment
import androidx.appcompat.app.AppCompatActivity
import example.demo.kotlin.utils.LogUtil

/**
 ***********************************************************************
 *Author: zbl
 *Time: 2020/1/19 9:24
 *Name:
 *Overview:
 *Usage:
 ***********************************************************************
 */
class TestActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.actvity_test)

        //getExternalStorageDirectory在安卓10中已弃用, 可以使用getExternalFilesDir 代替
        val externalStorageDirectory = Environment.getExternalStorageDirectory()

        val filesDir = this.filesDir
        val cacheDir = this.cacheDir
        val externalCacheDir = this.externalCacheDir
        val externalCacheFilesDirPictures = this.getExternalFilesDir(Environment.DIRECTORY_PICTURES)

        LogUtil.i("activity 获取缓存文件路径 filesDir : ${filesDir.absolutePath}")
        LogUtil.i("activity 获取缓存文件路径 cacheDir : ${cacheDir.absolutePath}")
        externalCacheDir?.let {
            LogUtil.i("activity 获取缓存文件路径 externalCacheDir : ${it.absolutePath}")
        }
        externalCacheFilesDirPictures?.let {
            LogUtil.i("activity 获取缓存文件路径 externalCacheFilesDirPictures : ${it.absolutePath}")
        }

        /*
             activity 获取缓存文件路径 filesDir : /data/user/0/example.demo.kotlin/files
             activity 获取缓存文件路径 cacheDir : /data/user/0/example.demo.kotlin/cache
             activity 获取缓存文件路径 externalCacheDir : /storage/emulated/0/Android/data/example.demo.kotlin/cache
             activity 获取缓存文件路径 externalCacheFilesDirPictures : /storage/emulated/0/Android/data/example.demo.kotlin/files/Pictures
         */

        val mFilesDir2 = this.application.filesDir
        val cacheDir2 = this.application.cacheDir
        val externalCacheDir2 = this.application.externalCacheDir
        val externalCacheFilesDirPictures2 = this.application.getExternalFilesDir(Environment.DIRECTORY_PICTURES)

        LogUtil.i("activity.getApplication() 获取缓存文件路径 filesDir2 : ${mFilesDir2.absolutePath}")
        LogUtil.i("activity.getApplication() 获取缓存文件路径 cacheDir2: ${cacheDir2.absolutePath}")
        externalCacheDir2?.let {
            LogUtil.i("activity.getApplication() 获取缓存文件路径 externalCacheDir2 : ${it.absolutePath}")
        }

        externalCacheFilesDirPictures2?.let {
            LogUtil.i("activity.getApplication() 获取缓存文件路径 externalCacheFilesDirPictures2: ${it.absolutePath}")
        }

        /*
             activity.getApplication() 获取缓存文件路径 filesDir2 : /data/user/0/example.demo.kotlin/files
             activity.getApplication() 获取缓存文件路径 cacheDir2: /data/user/0/example.demo.kotlin/cache
             activity.getApplication() 获取缓存文件路径 externalCacheDir2 : /storage/emulated/0/Android/data/example.demo.kotlin/cache
             activity.getApplication() 获取缓存文件路径 externalCacheFilesDirPictures2: /storage/emulated/0/Android/data/example.demo.kotlin/files/Pictures
         */

        val filesDir3 = this.applicationContext.filesDir
        val cacheDir3 = this.applicationContext.cacheDir
        val externalCacheDir3 = this.applicationContext.externalCacheDir
        val externalCacheFilesDirPictures3 = this.applicationContext.getExternalFilesDir(Environment.DIRECTORY_PICTURES)

        LogUtil.i("activity.getApplicationContext() 获取缓存文件路径 filesDir3 : ${filesDir3.absolutePath}")
        LogUtil.i("activity.getApplicationContext() 获取缓存文件路径 cacheDir3 : ${cacheDir3.absolutePath}")
        externalCacheDir3?.let {
            LogUtil.i("activity.getApplicationContext() 获取缓存文件路径 externalCacheDir3 : ${it.absolutePath}")
        }
        externalCacheFilesDirPictures3?.let {
            LogUtil.i("activity.getApplicationContext() 获取缓存文件路径 externalCacheFilesDirPictures3 : ${it.absolutePath}")

        }

        /*
             activity.getApplicationContext() 获取缓存文件路径 filesDir3 : /data/user/0/example.demo.kotlin/files
             activity.getApplicationContext() 获取缓存文件路径 cacheDir3 : /data/user/0/example.demo.kotlin/cache
             activity.getApplicationContext() 获取缓存文件路径 externalCacheDir3 : /storage/emulated/0/Android/data/example.demo.kotlin/cache
             activity.getApplicationContext() 获取缓存文件路径 externalCacheFilesDirPictures3 : /storage/emulated/0/Android/data/example.demo.kotlin/files/Pictures
         */
    }
}