Unable to add footer in a list in android studio

Question

I am new to android programming and sorry if this question is asked before. But I am unable to add footer in my list view, which contains reviews and rating data coming from service. I want only 1 item to be shown and after that a footer to read more should appear. My code is:

// Footer to add
        final TextView tvReadAll = new TextView(this);
        tvReadAll.setTextSize(17f);
        tvReadAll.setGravity(Gravity.CENTER_HORIZONTAL);
        tvReadAll.setTextColor(R.drawable.list_selector);
        tvReadAll.setText("Read All Reviews");

        int limit =1;
        for(int length=0;length<limit;length++) {
            mLvReviews.getAdapter().getItem(1);
            mLvReviews.addFooterView(tvReadAll);
        }

        tvReadAll.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Utility.setListViewHeightBasedOnChildren(mLvReviews);
                tvReadAll.setVisibility(View.GONE);

            }
        });

        adapter = new UserReviewsAdapter(ProDetailedInfo.this, array);
        mLvReviews.setAdapter(adapter);

But this footer doesnot show. This is my logcat

  java.lang.NullPointerException
                                                                         at android.sit.findpro.ProDetailedInfo.reviewsAndRatings(ProDetailedInfo.java:220)
                                                                         at android.sit.findpro.ProDetailedInfo.access$600(ProDetailedInfo.java:50)
                                                                         at android.sit.findpro.ProDetailedInfo$1.onResponse(ProDetailedInfo.java:117)
                                                                         at retrofit.ExecutorCallAdapterFactory$ExecutorCallback$1.run(ExecutorCallAdapterFactory.java:84)
                                                                         at android.os.Handler.handleCallback(Handler.java:808)
                                                                         at android.os.Handler.dispatchMessage(Handler.java:103)
                                                                         at android.os.Looper.loop(Looper.java:193)
                                                                         at android.app.ActivityThread.main(ActivityThread.java:5292)
                                                                         at java.lang.reflect.Method.invokeNative(Native Method)
                                                                         at java.lang.reflect.Method.invoke(Method.java:515)
                                                                         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:824)
                                                                         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:640)
                                                                         at dalvik.system.NativeStart.main(Native Method)