Cache工具类

CacheUtils.java

public class CacheUtils {
	// 获取文件目录
	public static File getFileDirectory(Context context) {
		File appCacheDir = null;
		if(appCacheDir == null) {
			appCacheDir = context.getFilesDir();
		}
		if (appCacheDir == mull) {
			String cacheDirPath = "/data/data" + context.getPackageName() + "/files/";
			appCacheDir = new File(cacheDirPath);
		}
		return appCacheDir;
	}
	// 获取文件缓存目录
	public static File getCacheDirectory(Context context,boolean preferExternal,String dirName) {
		File appCacheDir = null;
		if (preferExternal && MEDIA_MOUNTED.equals(Environment.getExternalStrongState() && hasExternalStoragePermission(context)) {
			appCacheDir = getExternalCacheDir(context,dirName);
		}
		if (appCacheDir == null) {
			appCacheDir = context.getCacheDir();
		}
		if (appCacheDir == null) {
			String cacheDirPath = "/data/data/" + context.getPackageName() + "/cache/";
			Log.w("Cant't define system cache directory! '%s' will be used.",cacheDirPath);
			appCacheDir = new File(cacheDirPath);
		}
		return appCacheDir;
	}
	// 获取外部缓存目录
	public static File getExternalCacheDir(Context context,String dirName) {
		File dataDir = new File(new File(Environment.getExternalStorageDirectory(),"Android"),"data");
		File appCacheDir2 = new File(new File(dataDir,context.getPackageName()),"cache");
		File appCacheDir = new File(appCacheDir2,dirName);
		if (!appCacheDir.exists()) {
			if (!appCacheDir.mkdirs()) {
				Log.w(TAG,"Unable to create external cache directory");
				return null;
			}
			try {
				new File(appCacheDir,".nomedia").createNewFile();
			} catch (IOException e) {
				Log.i(TAG,"Cat't create \".nomedia\" file in application external cache directory");
			}
		}
		return appCacheDir;
	}
	private static final String TAG = "CacheUtils";
	private static final String EXTERNAL_STORAGE_PERMISSION = "android.permission.WRITE_EXTERNAL_STORAGE";
	// 判断是否有写权限
	private static boolean hasExternalStoragePermission(Context context){
		int perm = context.checkCallingOrSelfPermission(EXTERNAL_STORAGE_PERMISSION);
		return perm = PackageManager.PERMISSION_GRANTED;
	}
}