RecycleView 实现携程酒店图片滑动到最后一张时跳转到相册

Posted 2022-05-17 小猪快跑22

前言： 就是为了实现如下图的这种效果，滑动到最后一张图片时，跳转到该酒店的相册。

实现方式就是使用 RecycleView 加上 PagerSnapHelper。

PagerSnapHelper 的作用就是让 RecycleView 每次只能滑动一个 Item。

Adapter 的最后一个加上如上图红框框出来的 View ，即下面的 STLview。在 STLView 里面会有个简单的动画效果。

STLView 代码如下：

public class STLView extends FrameLayout 
    private ImageView mImgArrow;
    private TextView mTxtHint;
    private boolean mIsPullStatus = true;

    public STLView(Context context) 
        this(context, null);
    

    public STLView(Context context, @Nullable AttributeSet attrs) 
        this(context, attrs, 0);
    

    public STLView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) 
        super(context, attrs, defStyleAttr);
        init(context, attrs, defStyleAttr);
    

    private void init(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr) 
        LayoutInflater.from(context).inflate(R.layout.hotel_view_stl, this, true);
        mImgArrow = findViewById(R.id.img_arrow);
        mTxtHint = findViewById(R.id.txt_hint);
        bindHint();
    

    public void setPullStatus(boolean isPullStatus) 
        if(mIsPullStatus == isPullStatus) 
            return;
        
        mIsPullStatus = isPullStatus;
        bindHint();
        animArrow();
    

    private void bindHint() 
        if(mIsPullStatus) 
            mTxtHint.setText("查看更多");

         else 
            mTxtHint.setText("释放进相册");
        
    

    private void animArrow() 
        if(mIsPullStatus) 
            ObjectAnimator.ofFloat(mImgArrow, "rotation", 180f, 00f)
                    .setDuration(getResources().getInteger(android.R.integer.config_shortAnimTime))
                    .start();
         else 
            ObjectAnimator.ofFloat(mImgArrow, "rotation", 0f, 180f)
                    .setDuration(getResources().getInteger(android.R.integer.config_shortAnimTime))
                    .start();
        
    

里面的代码很简单，就是简单的箭头旋转的动效。看看下面的 adapter ，如下：

public class TestAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> 

    private static final int TYPE_TEXT = 0;
    private static final int TYPE_STL = TYPE_TEXT + 1;

    private List<String> dataList;

    public TestAdapter() 
        dataList = new ArrayList<>();
    

    public void setDataList(List<String> dataList) 
        this.dataList.clear();
        this.dataList.addAll(dataList);
        notifyDataSetChanged();
    

    @NonNull
    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) 
        if (viewType == TYPE_TEXT) 
            return new TestHolder(LayoutInflater.from(parent.getContext()).inflate(R.layout.test_holder_item_view, parent, false));
         else  
            STLView stlView = new STLView(parent.getContext());
            stlView.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.MATCH_PARENT));
            return new STLHolder(stlView);
        
    

    @Override
    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) 
        if (holder instanceof TestHolder) 
            ((TestHolder) holder).bindView(position);
        
    

    @Override
    public int getItemViewType(int position) 
        if (position < dataList.size()) 
            return TYPE_TEXT;
         else 
            return TYPE_STL;
        
    

    @Override
    public int getItemCount() 
        int cnt = hasData() ? 1 : 0;
        cnt += dataList.size();
        return cnt;
    

    private boolean hasData() 
        return dataList.size() > 0;
    

    class TestHolder extends RecyclerView.ViewHolder 

        private TextView tv ;

        public TestHolder(@NonNull View itemView) 
            super(itemView);
            tv = itemView.findViewById(R.id.test_tv);
        

        public void bindView(int position) 
            tv.setText(dataList.get(position));
        
    

    class STLHolder extends RecyclerView.ViewHolder 

        public STLHolder(@NonNull View itemView) 
            super(itemView);
        
    

代码也很简单，就是在后面添加一个 STLView 。

下面是调用的地方了。如下：

public class TestPagerSnapHelperActivity extends AppCompatActivity 

    private RecyclerView recyclerView;
    private TestAdapter testAdapter;
    private STLView mSTLView;
    private boolean mOpenAll;

    public static void enter(Context context) 
        Intent intent = new Intent(context, TestPagerSnapHelperActivity.class);
        context.startActivity(intent);
    

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) 
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_pager_snaphelper_layout);

        recyclerView = findViewById(R.id.recycle_view);
        recyclerView.setLayoutManager(new LinearLayoutManager(this, RecyclerView.HORIZONTAL, false));
        testAdapter = new TestAdapter();
        recyclerView.setAdapter(testAdapter);

        SnapHelper pagerSnapHelper = new PagerSnapHelper();
        pagerSnapHelper.attachToRecyclerView(recyclerView);

        List<String> dataList = new ArrayList<>(5);
        dataList.add("安徽");
        dataList.add("浙江");
        dataList.add("上海");
        dataList.add("北京");
        dataList.add("江苏");
        testAdapter.setDataList(dataList);

        recyclerView.addOnChildAttachStateChangeListener(new RecyclerView.OnChildAttachStateChangeListener() 
            @Override
            public void onChildViewAttachedToWindow(@NonNull View view) 
                if (view instanceof STLView) 
                    mSTLView = (STLView) view;
                
            

            @Override
            public void onChildViewDetachedFromWindow(@NonNull View view) 
                if (view instanceof STLView) 
                    mSTLView = null;
                
            
        );

        recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() 
            @Override
            public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) 
                super.onScrollStateChanged(recyclerView, newState);
                if (mOpenAll && newState == RecyclerView.SCROLL_STATE_IDLE) 
                    // 这里面实现跳转逻辑
                    Log.e("pagerHelper", "open");
                
            

            @Override
            public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) 
                super.onScrolled(recyclerView, dx, dy);
                mOpenAll = !canScrollMore();
                Log.e("pagerHelper", "mOpenAll = " + mOpenAll);
                if (mSTLView != null) 
                    mSTLView.setPullStatus(!mOpenAll);
                
            
        );
    

    private boolean canScrollMore() 
        // 正数表示向左的滑动检测，负数表示向右的滑动检测
        return recyclerView.canScrollHorizontally(10);
    

就是利用 PagerSnapHelper 实现 RecycleView 每次只滑动一项。然后监听滑动事件，是否不能继续滑动且停止滑动的时候就可以实现跳转逻辑了。