java - 如何在 Android 上创建和/或附加到文件？

Question

这就是我正在做的事情:

    static void writeToFile(String text) {
    try {
        synchronized (fileLock) {
            File external = Environment.getExternalStorageDirectory();
            String sdcardPath = external.getPath();
            FileWriter filewriter = new FileWriter(sdcardPath
                    + "/Documents/myfile.txt", true);
            BufferedWriter out = new BufferedWriter(filewriter);

            out.write(text);

            out.close();
            filewriter.close();
        }
    } catch (Exception e) {
        android.util.Log.d("failed to save file", e.toString());
    }
}

在打开文件时出现以下异常:

java.io.FileNotFoundException: /mnt/sdcard/Documents/myfile.txt: 
    open failed: ENOENT (No such file or directory)

1. 目录/mnt/sdcard/Documents/根据 Root Browres 存在
2. 应用程序 list 确实包含 <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
3. myfile.txt不存在，我希望创建或附加它

如何在 Android 上创建或附加文件？

更新 这是我的 AndroidManifest.xml:

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.mytest"
    android:versionCode="1"
    android:versionName="1.0" >
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="15" />

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/title_activity_main" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

Answer 1

首先您必须创建文件，然后附加到该文件，这是创建文件的代码

    sFileName = "Android.txt";
    File root=Environment.getExternalStorageDirectory();

    File textfile = new File(root, sFileName);
    textfile.createNewFile();

权限:

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />