Where should I write a temporary file?

Question

In android devices external memory may or may not be present.

I am writing an app which in one case stream mp3 from URL & stores it in a file in memory for temporary purpose.

But I want to be sure that, that file will get created.

First I thought of using getCacheDir , but it is mentioned:

These files will be ones that get deleted first when the device runs low on storage. There is no guarantee when these files will be deleted. Note: you should not rely on the system deleting these files for you; you should always have a reasonable maximum, such as 1 MB, for the amount of space you consume with cache files, and prune those files when exceeding that space.

So, then I thought of using getExternalCacheDir , but then I'm not sure that the device will contain external memory or not.

There is one more optional issue: Before saving the file in memory, I want to check if the directory has enough space. How can this be done?

Update

I also thought of creating a file in Environment.getDownloadCacheDirectory(), as probably it will be available on every device.

File f3 = new File(Environment.getDownloadCacheDirectory(), "Temp.txt");
    if (!f3.exists()) {
        f3.createNewFile();
    } 

But got below error trace in createNewFile():

java.io.IOException: Permission denied
    at java.io.File.createNewFileImpl(Native Method)
    at java.io.File.createNewFile(File.java:1257)
    at com.example.activitylifecycle.MyStreamingApp.startStream(MyStreamingApp.java:42)
    at com.example.activitylifecycle.MyStreamingApp.onCreate(MyStreamingApp.java:23)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1072)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1836)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1893)
    at android.app.ActivityThread.access$1500(ActivityThread.java:135)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1054)
    at android.os.Handler.dispatchMessage(Handler.java:99)
    at android.os.Looper.loop(Looper.java:150)
    at android.app.ActivityThread.main(ActivityThread.java:4385)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:507)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:849)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:607)
    at dalvik.system.NativeStart.main(Native Method)

Manifest File:

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.activitylifecycle"
    android:versionCode="1"
    android:versionName="1.0" >

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

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

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.activitylifecycle.ActivityLifeCycle"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name=".MyStreamingApp"
            android:label="@string/app_name" >
            <intent-filter android:priority="100" >
                <action android:name="com.example.activitylifecycle.MYSTREAMINGAPP" />

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

</manifest>

Please suggest. Thank You

Answer 1

you write the file in /data/data/. your-package-name is the same name mentioned in AndroidManifest.xml file.