#2 refactor android code

src/android/src/main/java/com/RNFetchBlob/RNFetchBlob.java

     @ReactMethod
     public void flush(String taskId) {
         try {
-            new File(RNFetchBlobFS.TempFilePath + taskId).delete();
+            new File(RNFetchBlobFS.getTmpPath(this.getReactApplicationContext(), taskId)).delete();
         } catch(Exception err) {
             WritableMap args = Arguments.createMap();
             args.putString("event", "error");

src/android/src/main/java/com/RNFetchBlob/RNFetchBlobFS.java

  */
 public class RNFetchBlobFS {
 
-    static String DocumentDir = Environment.getExternalStorageDirectory().toString();
-    static String TempFilePath = Environment.getExternalStorageDirectory().toString() + "/RNFetchBlobCache/dltmp";
-
     ReactApplicationContext mCtx;
     DeviceEventManagerModule.RCTDeviceEventEmitter emitter;
 
+    static public String getTmpPath(ReactApplicationContext ctx, String taskId) {
+        return ctx.getFilesDir() + "/RNFetchBlobTmp_" + taskId;
+    }
+
 
     RNFetchBlobFS(ReactApplicationContext ctx) {
         this.mCtx = ctx;
     public void readStream(String taskId, String encoding) {
         try {
 
-            FileInputStream fs = mCtx.openFileInput(RNFetchBlobFS.TempFilePath + taskId);
+            FileInputStream fs = mCtx.openFileInput(mCtx.getFilesDir() + "/fetchblobtmp_"+ taskId);
             byte[] buffer = new byte[1024];
             int cursor = 0;
             boolean error = false;

src/android/src/main/java/com/RNFetchBlob/RNFetchBlobFileHandler.java

 
 import com.facebook.react.bridge.Arguments;
 import com.facebook.react.bridge.Callback;
+import com.facebook.react.bridge.ReactApplicationContext;
 import com.facebook.react.bridge.ReactContext;
 import com.facebook.react.bridge.WritableMap;
 import com.facebook.react.modules.core.DeviceEventManagerModule;
     ReactContext mCtx;
     String mTaskId;
 
-    RNFetchBlobFileHandler(ReactContext ctx, String taskId, Callback onResponse) {
-        // save temp file to RNFetchBlobCache/dltmp${taskId}
-        super(new File(RNFetchBlobFS.TempFilePath + taskId), false, false);
+    RNFetchBlobFileHandler(ReactApplicationContext ctx, String taskId, Callback onResponse) {
+        // save temp file to application storage
+        super(new File(RNFetchBlobFS.getTmpPath(ctx, taskId)), false, false);
         this.onResponse = onResponse;
         this.mTaskId = taskId;
         this.mCtx = ctx;