我正在尝试实现无限/循环的recyclerview， 这是Adapter类的实现。
public class MyAdapter extends
RecyclerView.Adapter<RecyclerView.ViewHolder> {
private static final String TAG = MyAdapter.class.getSimpleName();
private static final int VIEW_TYPE_NORMAL = 1;
private static final int VIEW_TYPE_GAP = 2;
private Context mContext;
private final List<ChannelInfo> mChannelInfoList;
private LinearTunerClickListener mClickListener;
public MyAdapter(
Context context, List<ChannelInfo> channelInfoList, LinearTunerClickListener mClickListener) {
mChannelInfoList = channelInfoList;
mContext = context;
this.mClickListener = mClickListener;
}
@NonNull
@Override
public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
//Variable to store inflated view based on VIEW TYPE.
View inflatedView;
BaseHolder baseHolder;
if (viewType == VIEW_TYPE_NORMAL) {
inflatedView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.item_some_holder1, parent, false);
baseHolder = new SomeHolder1(inflatedView);
} else {
inflatedView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.item_some_holder2, parent, false);
baseHolder = new SomeHolder2(inflatedView);
}
return baseHolder;
}
@Override
public void onBindViewHolder(@NonNull RecyclerView.ViewHolder myViewHolder, int position) {
if (mContext != null) {
if (mChannelInfoList != null) {
mPos = position % mChannelInfoList.size();
// do stuff
}
}
}
@Override
public int getItemViewType(int position) {
bPos = position % mChannelInfoList.size();
int viewType;
if (bPos != mChannelInfoList.size() - 1) {
viewType = VIEW_TYPE_NORMAL;
} else {
// If current position is last item, then return view type as GAP
viewType = VIEW_TYPE_GAP;
}
return viewType;
}
@Override
public int getItemCount() {
return Integer.MAX_VALUE;
}
}
这是保存适配器并获取索引的位置（从包中滚动所需的位置）
public class MainActivity extends AppCompatActivity implements SomeListener {
private static final String TAG = "MainActivity" + " : ";
@BindView(R.id.activity_main2_rv)
RecyclerView mRecyclerView;
private MyAdapter mAdapter;
private List<ChannelInfo> mChannelInfoList = new ArrayList<>();
private SnapHelper mSnapHelper;
private CenterLayoutManager mLayoutManager;
private Integer mIndex;
private String mChannelNo;
private int mFocusPos = -1;
private View mFocusedView;
private int pos = -1;
private int BIG = Integer.MAX_VALUE;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.linear);
ButterKnife.bind(this);
Log.e(TAG, "onCreate(): ");
bundleOperation();
setUpRecycler();
setUpSnapHelper();
setAdapter();
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
if (mLayoutManager != null) {
mLayoutManager.scrollToPosition(Integer.MAX_VALUE/2);
mRecyclerView.smoothScrollToPosition(Integer.MAX_VALUE/2 + (mIndex-3));
}
}
}, 300);
}
private void bundleOperation() {
Bundle bundle = getIntent().getExtras();
if (bundle != null) {
Log.d(TAG, "get Bundle: ");
mIndex = bundle.getInt("index");
mChannelNo = bundle.getString("ch_no");
Log.v(TAG, " we have, " + " index : " + mIndex + " and " + " ch_no : " + mChannelNo);
mChannelInfoList = bundle.getParcelableArrayList("list");
}
}
private void setUpRecycler() {
mLayoutManager = new CenterLayoutManager(
this,
CenterLayoutManager.HORIZONTAL,
false
);
mRecyclerView.setLayoutManager(mLayoutManager);
mRecyclerView.setItemAnimator(new DefaultItemAnimator());
}
private void setUpSnapHelper() {
mSnapHelper = new LinearSnapHelper();
mSnapHelper.attachToRecyclerView(mRecyclerView);
}
private void setAdapter() {
mAdapter = new MyAdapter(this, mChannelInfoList, this);
mRecyclerView.setAdapter(mAdapter);
mAdapter.notifyDataSetChanged();
}
}
仅供参考，我使用了一个自定义布局管理器来实现轮播效果，所以现在让我说，列表大小现在总共有12个项目
mLayoutManager.scrollToPosition(Integer.MAX_VALUE/2);
mRecyclerView.smoothScrollToPosition(Integer.MAX_VALUE/2 + (mIndex-3));
逻辑工作正常。------------------------
它完全错过了索引。
您能提示我要去哪里调试或类似的东西，迷迷了许多小时。 如果您需要Center Layout Manager类，
public class CenterLayoutManager extends LinearLayoutManager {
private static final float BALANCING_FACTOR = 0.78f;
private static final float fastScrollSpeedFactor = 50f;
public CenterLayoutManager(Context context) {
super(context);
}
public CenterLayoutManager(Context context, int orientation, boolean reverseLayout) {
super(context, orientation, reverseLayout);
}
public CenterLayoutManager(Context context,
AttributeSet attrs,
int defStyleAttr, int defStyleRes) {
super(context, attrs, defStyleAttr, defStyleRes);
}
@Override
public void smoothScrollToPosition(RecyclerView recyclerView, RecyclerView.State state,
int position) {
RecyclerView.SmoothScroller smoothScroller =
new CenterSmoothScroller(recyclerView.getContext()) {
@Override
protected float calculateSpeedPerPixel(DisplayMetrics displayMetrics) {
return fastScrollSpeedFactor / displayMetrics.densityDpi;
}
};
smoothScroller.setTargetPosition(position);
startSmoothScroll(smoothScroller);
}
@Override
public PointF computeScrollVectorForPosition(int targetPosition) {
return super.computeScrollVectorForPosition(targetPosition);
}
@Override
public int scrollHorizontallyBy(int dx, RecyclerView.Recycler recycler,
RecyclerView.State state) {
int scrolled = super.scrollHorizontallyBy(dx, recycler, state);
// some logic to show center item, ZOOMED in
return scrolled;
}
@Override
public void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) {
super.onLayoutChildren(recycler, state);
// scrollHorizontallyBy(0, recycler, state);
}
private static class CenterSmoothScroller extends LinearSmoothScroller {
CenterSmoothScroller(Context context) {
super(context);
}
@Override
public int calculateDtToFit(int viewStart, int viewEnd, int boxStart,
int boxEnd, int snapPreference) {
return (boxStart + (boxEnd - boxStart) / 2) - (viewStart + (viewEnd - viewStart) / 2);
}
}
}
请问我是否需要更广泛的情况来了解情况 如果没有涵盖上述情况，请尝试避免直接放置链接引用。 谢谢