Android：創建文件夾並新建txt寫入數據

以前的代碼拿過來總結，意外的就整成一個類了，不過倒也方便，我也不闡述了，就直接說怎麼用吧

1.首先肯定是在AndroidManifest的文件里加寫入SD卡的權限，代碼如下：

<!--SD卡讀寫的權限-->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

2.興建一個類，我這邊名字命名的是FileOperations

package cc.booku.owlbox.FileOperations;

import android.app.Activity;
import android.content.pm.PackageManager;
import android.support.v4.app.ActivityCompat;
import android.util.Log;

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

/**
 * Created by yangwenlong on 2020/5/16.
 */

public class FileoOperations {


    private static final int REQUEST_EXTERNAL_STORAGE = 1;
    private static String[] PERMISSIONS_STORAGE = {"android.permission.READ_EXTERNAL_STORAGE", "android.permission.WRITE_EXTERNAL_STORAGE"};

    public static void verifyStoragePermissions(Activity activity) {
        try {
            //檢測是否有寫的權限
            int permission = ActivityCompat.checkSelfPermission(activity, "android.permission.WRITE_EXTERNAL_STORAGE");
            if (permission != PackageManager.PERMISSION_GRANTED) {
                // 沒有寫的權限，去申請寫的權限，會彈出對話框
                ActivityCompat.requestPermissions(activity, PERMISSIONS_STORAGE, REQUEST_EXTERNAL_STORAGE);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }


    public static void writeData(String url, String name, String content) {
        String filePath = url;
        String fileName = name + ".txt";
        writeTxtToFile(content, filePath, fileName);
    }

    // 將字符串寫入到文本文件中
    private static void writeTxtToFile(String strcontent, String filePath, String fileName) {
        //生成文件夾之後，再生成文件，不然會出錯
        makeFilePath(filePath, fileName);

        String strFilePath = filePath + fileName;
        // 每次寫入時，都換行寫
        String strContent = strcontent + "\r\n";
        try {
            File file = new File(strFilePath);
            if (!file.exists()) {
                Log.d("TestFile", "Create the file:" + strFilePath);
                file.getParentFile().mkdirs();
                file.createNewFile();
            }
            RandomAccessFile raf = new RandomAccessFile(file, "rwd");
            raf.seek(file.length());
            raf.write(strContent.getBytes());
            raf.close();
        } catch (Exception e) {
            Log.e("TestFile", "Error on write File:" + e);
        }
    }

    //生成文件
    private static File makeFilePath(String filePath, String fileName) {
        File file = null;
        makeRootDirectory(filePath);
        try {
            file = new File(filePath + fileName);
            if (!file.exists()) {
                file.createNewFile();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return file;
    }


    //判斷文件是否存在
    public static boolean fileIsExists(String strFile) {
        try {
            File f = new File(strFile);
            if (!f.exists()) {
                return false;
            }
        } catch (Exception e) {
            return false;
        }
        return true;
    }


    //生成文件夾
    public static void makeRootDirectory(String filePath) {
        File file = null;
        try {
            file = new File(filePath);
            //不存在就新建
            if (!file.exists()) {
                file.mkdir();
            }
        } catch (Exception e) {
            Log.i("error:", e + "");
        }
    }

}

3.在activity裏面調用，我這邊給個案例

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

    //申請SD卡讀寫的權限
    FileoOperations.verifyStoragePermissions(MainActivity.this);
    //創建文件夾
    FileoOperations.makeRootDirectory("/storage/emulated/0/OwlDatabase/");
    //創建文件並寫入數據
    wtest();

}

//對應的函數

private void wtest() {

        //判斷文件是否存在
       if (!FileoOperations.fileIsExists("/storage/emulated/0/OwlDatabase/" + i + "name" + ".txt")){
         //writeData（文件路徑，文件名，要寫入的字符串）
       FileoOperations.writeData("/storage/emulated/0/OwlDatabase/", i + "name", "添加Flag把狀態欄設爲可繪製模式");
        }
    
}

至此就寫入完成了~