Question

应用程序记录传感器数据并将数据写入.txt文件到手机SD卡中。

在数据收集过程中，可以随时按停止按钮停止写入。

相关的写作部分如下：

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;

import android.widget.CheckBox;
import android.widget.EditText;

public class DataCollector {

    File myFile;
    FileOutputStream fOut;
    OutputStreamWriter myOutWriter;
    BufferedWriter myBufferedWriter;
    PrintWriter myPrintWriter;

    private boolean isStamped;
    private int timeStampNo;

    boolean accelerationWanted;
    boolean rotationRateWanted;
    boolean magneticFieldWanted;

    // constructor
    public DataCollector() {

        isStamped = false;
        timeStampNo = 0;

        accelerationWanted = false;
        rotationRateWanted = false;
        magneticFieldWanted = false;
    }

    public void setStamp() {

        isStamped = true;
        timeStampNo++;
    }

    public void setFilePath(EditText txtName) {

        myFile = new File("/sdcard/ResearchData/" + txtName.getText() + ".txt");

        try {
            myFile.createNewFile();
        } catch (IOException e) {
            e.printStackTrace();
        }

        try {
            fOut = new FileOutputStream(myFile);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }

        myOutWriter = new OutputStreamWriter(fOut);
        myBufferedWriter = new BufferedWriter(myOutWriter);
        myPrintWriter = new PrintWriter(myBufferedWriter);

    }

    public void saveData(double[] acceleration, double[] rotationRate, double[] magneticField, long startTime, long currentTime) {

            myPrintWriter.write(currentTime - startTime + " " + acceleration[0] + " " + acceleration[1] + " " + acceleration[2] + " " + rotationRate[0] + " " + rotationRate[1] + " " + rotationRate[2] + " " + magneticField[0] + " " + magneticField[1] + " " + magneticField[2] + "\n");
    }

    public void stopSaving() {

        try {
            myOutWriter.close();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (NullPointerException e) {
            e.printStackTrace();
        }
        try {
            fOut.close();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (NullPointerException e) {
            e.printStackTrace();
        }

    }

}

无论我调用saveData（）和stopSaving（）的顺序如何，最后一行总是不完整的。在右边，我在主要活动中执行以下操作：

dataCollector.saveData();
dataCollector.stopSaving();

我先保存数据，然后停止保存。为什么最后一行仍然不完整？

知道如何解决这个问题吗？要么完成最后一行，要么丢弃它就可以了。

提前致谢！

Answer 1

在关闭前尝试使用flush：

public void stopSaving() {

    try {
        myPrintWriter.flush();
        myPrintWriter.close();
    } catch (IOException e) {
        e.printStackTrace();
    } catch (NullPointerException e) {
        e.printStackTrace();
    }
    try {
        myOutWriter.flush();
        myOutWriter.close();
    } catch (IOException e) {
        e.printStackTrace();
    } catch (NullPointerException e) {
        e.printStackTrace();
    }
    try {
        fOut.flush();
        fOut.close();
    } catch (IOException e) {
        e.printStackTrace();
    } catch (NullPointerException e) {
        e.printStackTrace();
    }

}

Answer 2

你应该在关闭之前刷新你的编写器对象。

如下所示：

    myOutWriter.flush();
    myOutWriter.close();

和

    fOut.flush();
    fOut.close();

文件关闭时写入txt文件的行不完整 - Android

2 个答案: