技術標籤：android studioandroid studiojava

我傻了，之前建立1M檔案的時候，我檢視檔案屬性總是發現檔案不是1M，一直以為是io流的原因，又是加flush和close也沒有用，然後今天我突發奇想的去adbshell看了一下檔案屬性，結果顯示是1M。然後重新測試了一下，pc端顯示不是1M，去adbshell裡仍然顯示1M，然後我把檔案管理關了重新開啟顯示是1M了。程式碼修改了一下，更加簡潔明瞭。

這次使用隨機讀寫的方式測試檔案內容，讀寫對比了長度和內容。特此記錄一下學習情況。後續新增讀寫效能的測試。

package com.example.testst
//mitac-bu
 

import android.os.Bundle
import android.widget.Button
import androidx.appcompat.app.AppCompatActivity
import java.io.File
import java.io.FileReader
import java.io.FileWriter
import java.io.IOException
import java.text.SimpleDateFormat
import java.util.*

class MainActivity : AppCompatActivity() {
    private
 
 var path: String? = null
    private var mFileWriter: FileWriter? = null
    private val LENGTH = 1024*1024;
    var mWriterBuffer: CharArray? = null
    var mReaderBuffer: CharArray? = null
    private var str: String? = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
    override fun onCreate
 
(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        val btn = findViewById<Button>(R.id.button)
        btn.setOnClickListener {
            val random=Random()
            var bReturn = true
            val date = Date()
            val timeTemp: String = SimpleDateFormat("yyyyMMdd_HHmmss").format(date.time)
            path = getExternalFilesDir("")!!.absolutePath
            val file = File(path + File.separator + timeTemp + ".txt")
            mWriterBuffer = CharArray(LENGTH)
            mReaderBuffer = CharArray(LENGTH + 10)
            try {
                for (i in 0 until LENGTH) {
                    val number: Int = random.nextInt(62)
                    mWriterBuffer!![i] = str!![number]
                }
                mFileWriter = FileWriter(file)
                mFileWriter!!.write(mWriterBuffer)
                mFileWriter!!.close()
                val mFileReader = FileReader(file)
                val iRead = mFileReader.read(mReaderBuffer)
                mFileReader.close()
                if (iRead != LENGTH) {
                    println("The length isn't correct.")
                    bReturn = false
                } else {
                    println("The length is correct.")
                }
                var bSame = true
                for (i in 0 until LENGTH) {
                    if (mReaderBuffer!![i] != mWriterBuffer!![i]) {
                        bSame = false
                    }
                }
                if (bSame) {
                    println("The file is correct.")
                } else {
                    println("The file isn't correct.")
                    bReturn = false
                }
                if (bReturn) {
                    println("Pass")
                } else {
                    println("Fail")
                }

            } catch (e: IOException) {
                e.printStackTrace()
            }
            Thread.sleep(1000);
        }
    }
}