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Android使用RecycleView实现跑马灯和轮播图效果

龙旋 | 1282 2021-06-11 17:48 0 0 0
UniSMS (合一短信)

先看下效果图:





利用Recycleview实现这个效果最主要的一个方法就是这个方法

        mSnapHelper = new LinearSnapHelper();        mSnapHelper.attachToRecyclerView(mRecyclerView);


这个方法的作用是使得RecycelView像ViewPager一样的效果,一次只能滑一页,而且居中显示。

然后利用Handler来实现无限轮播的效果,在Adapter中要注意

    @Override    public int getItemCount() {        return Integer.MAX_VALUE;    }
 Glide.with(mContext).load(mDatas.get(position % mDatas.size())).into(mImageView);


getItemCount中返回一个无穷大达到无限录播的效果,在填充数据时取余防止索引越界,然后自定义Layoutmanger

public class MyBannerManger extends LinearLayoutManager {
private RecyclerView mRecyclerView; private final InterValHander mHander; private static final int INTERVAL = 3000; private boolean mIsLayoutComplete = false; private static int position = 1; private LinearSnapHelper mSnapHelper;
public MyBannerManger(Context context, RecyclerView recyclerView) { super(context); setOrientation(HORIZONTAL); mRecyclerView = recyclerView; mHander = new InterValHander(this); mRecyclerView.setOnTouchListener(new View.OnTouchListener() { @Override public boolean onTouch(View v, MotionEvent event) { if(event.getAction() == MotionEvent.ACTION_DOWN){ mHander.removeCallbacksAndMessages(null); }else if(event.getAction() == MotionEvent.ACTION_UP){ mHander.sendEmptyMessageDelayed(position,INTERVAL); } return false; } }); }
@Override public void onAttachedToWindow(RecyclerView view) { super.onAttachedToWindow(view); mSnapHelper = new LinearSnapHelper(); mSnapHelper.attachToRecyclerView(mRecyclerView); }
@Override public void onLayoutCompleted(RecyclerView.State state) { super.onLayoutCompleted(state); if (!mIsLayoutComplete) { mHander.sendEmptyMessageDelayed(position,INTERVAL); }
mIsLayoutComplete = true; }
private RecyclerView getRecyclerView(){ return mRecyclerView; }
static class InterValHander extends Handler {
private WeakReference<MyBannerManger> mWeakReference; private MyBannerManger mBannerManger;
public InterValHander(MyBannerManger myBannerManger) { mWeakReference = new WeakReference<>(myBannerManger); mBannerManger = myBannerManger; }
@Override public void handleMessage(Message msg) { LogUtils.LogE(msg.toString()); mBannerManger.getRecyclerView().smoothScrollToPosition(position); sendEmptyMessageDelayed(0,INTERVAL); position++;
} }

@Override public void smoothScrollToPosition(RecyclerView recyclerView, RecyclerView.State state, int position) { LogUtils.LogE("smoothScrollToPosition"); LinearSmoothScroller smoothScroller = new LinearSmoothScroller(recyclerView.getContext()) { // 返回:滑过1px时经历的时间(ms)。 @Override protected float calculateSpeedPerPixel(DisplayMetrics displayMetrics) { float f = 150f / displayMetrics.densityDpi; LogUtils.LogE("F = "+f); return 0.5f; } };
smoothScroller.setTargetPosition(position); startSmoothScroll(smoothScroller); }
@Override public void onScrollStateChanged(int state) { if(state == SCROLL_STATE_IDLE){ position = getPosition(mSnapHelper.findSnapView(this))+1;        }    }


处理逻辑:

public class RActivity extends AppCompatActivity {    private RecyclerView mRecyclerView;    private String[] mStrings = {"南京南站","龙眠大道","学则路","仙鹤门","仙鹤名苑","紫东国际创意园!"};
@Override protected void onCreate(@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_r); mRecyclerView = findViewById(R.id.rv); List<String> list = Arrays.asList(Images.imageUrls); mRecyclerView.setLayoutManager(new MyBannerManger(this,mRecyclerView)); RAdapter rAdapter = new RAdapter(this, list); mRecyclerView.setAdapter(rAdapter); }}


到这里就结束啦。

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