Java tutorial
//package com.java2s; import android.content.Context; import android.content.pm.PackageManager; import android.os.Environment; import java.io.File; import java.io.IOException; import static android.os.Environment.MEDIA_MOUNTED; public class Main { private static final String EXTERNAL_STORAGE_PERMISSION = "android.permission.WRITE_EXTERNAL_STORAGE"; /** * Returns application cache directory. Cache directory will be created on SD card * <i>("/Android/data/[app_package_name]/cache")</i> if card is mounted and app has appropriate permission. Else - * Android defines cache directory on device's file system. * * @param context Application context * @return Cache {@link File directory}.<br /> * <b>NOTE:</b> Can be null in some unpredictable cases (if SD card is unmounted and * {@link android.content.Context#getCacheDir() Context.getCacheDir()} returns null). */ public static File getCacheDirectory(Context context) { return getCacheDirectory(context, true, "cache"); } public static File getCacheDirectory(Context context, boolean isCache, String customDir) { return getCacheDirectory(context, true, isCache, customDir); } /** * Returns application cache directory. Cache directory will be created on SD card * <i>("/Android/data/[app_package_name]/cache")</i> (if card is mounted and app has appropriate permission) or * on device's file system depending incoming parameters. * * @param context Application context * @param preferExternal Whether prefer external location for cache * @return Cache {@link File directory}.<br /> * <b>NOTE:</b> Can be null in some unpredictable cases (if SD card is unmounted and * {@link android.content.Context#getCacheDir() Context.getCacheDir()} returns null). */ public static File getCacheDirectory(Context context, boolean preferExternal, boolean cache, String customDir) { File appCacheDir = null; String externalStorageState; try { externalStorageState = Environment.getExternalStorageState(); } catch (NullPointerException e) { // (sh)it happens (Issue #660) externalStorageState = ""; } catch (IncompatibleClassChangeError e) { // (sh)it happens too (Issue #989) externalStorageState = ""; } if (preferExternal && MEDIA_MOUNTED.equals(externalStorageState) && hasExternalStoragePermission(context)) { appCacheDir = getExternalCacheDir(context, cache, customDir); } if (appCacheDir == null) { appCacheDir = context.getCacheDir(); } if (appCacheDir == null) { String cacheDirPath; cacheDirPath = "/data/data/" + context.getPackageName() + "/" + customDir + "/"; appCacheDir = new File(cacheDirPath); } return appCacheDir; } private static boolean hasExternalStoragePermission(Context context) { int perm = context.checkCallingOrSelfPermission(EXTERNAL_STORAGE_PERMISSION); return perm == PackageManager.PERMISSION_GRANTED; } private static File getExternalCacheDir(Context context, boolean cache, String customDir) { File dataDir = new File(new File(Environment.getExternalStorageDirectory(), "Android"), "data"); File appCacheDir = new File(new File(dataDir, context.getPackageName()), customDir); if (!appCacheDir.exists()) { if (!appCacheDir.mkdirs()) { return null; } try { new File(appCacheDir, ".nomedia").createNewFile(); } catch (IOException e) { } } return appCacheDir; } }