1. UI 效果

例如我们需要采集温度信息，可以不断写入一行一行的txt文本，读写文件操作即可

2. 调用示例

2.1 需要配置SD卡读写权限

    <uses-sdk
        android:minSdkVersion="17"
        android:targetSdkVersion="17" />

    <!-- 往sdcard中写入数据的权限 -->
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <!-- 在sdcard中创建/删除文件的权限 -->
    <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />

2.2 调用

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        for (int i = 0; i < 100; i++) {
            FileSaveUtil.writeFile("Temperature01.txt", String.format("Temperature : %.1f 摄氏度" , 30 + (float) i % 10));
        }
    }

}

3.工具类源码

package com.wu.sufadi;

import java.io.File;
import java.io.RandomAccessFile;

import android.os.Environment;

public class FileSaveUtil {

    public final static String FILE_PATH = Environment.getExternalStorageDirectory() + "/PhoneData/";

    public static void writeFile(String fileName, String content) {
        String strContent = content + "\n";
        try {
            File fileDir = new File(FILE_PATH);
            if (!fileDir.exists()) {
                fileDir.mkdirs();
                if (!fileDir.exists()) {
                    return;
                }
            }
            File file = new File(FILE_PATH, fileName);
            RandomAccessFile raf = new RandomAccessFile(file, "rw");
            raf.seek(file.length());
            raf.write(strContent.getBytes());
            raf.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static void delLogFile(String path) {
        File file = new File(path);
        if (file.exists()) {
            file.delete();
        }
    }
}