仿微信 未读消息 标识显示

01.gif

步骤：

• 基于RecyclerView
• 数据默认显示最后一个
• 监听 RecyclerView Scroll 方法

    ArrayList<String> sts = new ArrayList<>();
        for (int i = 0; i < 50; i++) {
            sts.add("第 " + i + " 条数据");
        }
        mRecyclerView.setHasFixedSize(true);
        final ScrollSpeedLinearLayoutManger layoutManager = new ScrollSpeedLinearLayoutManger(this);
        mRecyclerView.setLayoutManager(layoutManager);
        mItemAdapter = new ItemAdapter(this, sts);
        mRecyclerView.setAdapter(mItemAdapter);
        mRecyclerView.smoothScrollToPosition(mItemAdapter.getItemCount() - 1);

        mTxtNoReadingType.setText("^ 10 条未读");
        mTxtNoReadingType.startAnimation(AnimationUtils.loadAnimation(this, R.anim.in_x));

        mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
                super.onScrollStateChanged(recyclerView, newState);
            }

            @Override
            public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
                super.onScrolled(recyclerView, dx, dy);
                int position = layoutManager.findFirstVisibleItemPosition();
                Log.i(TAG, "onScrolled: position================" + position);
                if (mItemAdapter != null && position != 0) {
                    int count = mItemAdapter.getItemCount();
                    if(mTxtNoReadingType.getVisibility()==View.VISIBLE){
                        if (count - position == 10) {
                            mTxtNoReadingType.startAnimation(AnimationUtils.loadAnimation(MainActivity.this, R.anim.out_x));
                            mTxtNoReadingType.setVisibility(View.INVISIBLE);
                        }
                    }
                }
            }
        });

   <?xml version="1.0" encoding="utf-8"?>
   <set xmlns:android="http://schemas.android.com/apk/res/android"
      android:duration="500">
      <translate
         android:fromXDelta="100%"
         android:toXDelta="0%"
         />
   </set>

   <?xml version="1.0" encoding="utf-8"?>
   <set xmlns:android="http://schemas.android.com/apk/res/android"
      android:duration="500">
      <translate
         android:fromXDelta="0%"
         android:toXDelta="100%"
         />
   </set>