学了好久,终于实现了。分享一下代码吧。
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical"> <LinearLayout android:layout_width="wrap_content" android:layout_height="wrap_content"> <include layout="@layout/titlebar_home" /> </LinearLayout> <RelativeLayout android:layout_width="match_parent" android:layout_marginLeft="@dimen/horizontal_dimen_10dp" android:layout_marginRight="@dimen/horizontal_dimen_10dp" android:layout_height="wrap_content"> <android.support.v7.widget.RecyclerView android:id="@+id/recycler" android:layout_width="match_parent" android:layout_height="200dp" android:layout_alignParentStart="true" android:layout_marginStart="0dp"></android.support.v7.widget.RecyclerView> <com.example.bs.Home.BannerIndicator android:id="@+id/indicator" android:layout_width="match_parent" android:layout_height="32dp" android:layout_alignBottom="@+id/recycler" app:selectColor="@color/colorAccent" app:unselectedColor="#ffffff" app:radius="3dp" app:space="10dp"/> </RelativeLayout> </LinearLayout>
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package com.example.bs.Home; import android.content.Context; import android.support.annotation.NonNull; import android.support.v7.widget.RecyclerView; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.ImageView; import com.bumptech.glide.Glide; import com.example.bs.R; import java.util.List; public class BannerAdapter extends RecyclerView.Adapter<BannerAdapter.ViewHolder> { private List<Integer> list; private Context context; public BannerAdapter(Context context, List<Integer> list){ this.list=list; this.context=context; } @Override public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) { View view= LayoutInflater.from(parent.getContext()).inflate(R.layout.item_image,parent,false); return new ViewHolder(view); } @Override public void onBindViewHolder(@NonNull ViewHolder holder, int position) { Glide.with(context).load(list.get(position%list.size())).into(holder.imageView); } @Override public int getItemCount() { return Integer.MAX_VALUE; } class ViewHolder extends RecyclerView.ViewHolder { private ImageView imageView; public ViewHolder(View itemView) { super(itemView); imageView= (ImageView) itemView.findViewById(R.id.item_image); } } }
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package com.example.bs.Home; import android.content.Context; import android.content.res.TypedArray; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.support.annotation.Nullable; import android.util.AttributeSet; import android.view.View; import com.example.bs.R; public class BannerIndicator extends View { private int number; private int position = 0; private Paint paint = new Paint(); private int selectColor; private int unSelectColor; private float radius; private float space; public BannerIndicator(Context context) { this(context,null); } public BannerIndicator(Context context, @Nullable AttributeSet attrs) { super(context, attrs); TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.BannerIndicator); this.selectColor = typedArray.getColor(R.styleable.BannerIndicator_selectColor, Color.RED); this.unSelectColor = typedArray.getColor(R.styleable.BannerIndicator_unselectedColor, Color.BLACK); this.radius = typedArray.getDimension(R.styleable.BannerIndicator_radius, 10); this.space = typedArray.getDimension(R.styleable.BannerIndicator_space, 20); typedArray.recycle(); } { paint.setStyle(Paint.Style.FILL); paint.setAntiAlias(true); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); float startPosition = getWidth() / 2 - (radius * 2 * number + space * (number - 1)) / 2; canvas.save(); for (int i = 0; i < number; i++) { if (i == position) { paint.setColor(selectColor); } else { paint.setColor(unSelectColor); } canvas.drawCircle(startPosition + radius * (2 * i + 1) + i * space, getHeight() / 2, radius, paint); } canvas.restore(); } public void setNumber(int number) { this.number = number; } public void setPosition(int position) { this.position = position; invalidate(); } }
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package com.example.bs.Home; import android.content.Context; import android.support.v7.widget.LinearLayoutManager; import android.support.v7.widget.LinearSmoothScroller; import android.support.v7.widget.RecyclerView; import android.util.DisplayMetrics; /** * author Gao * date 2017/11/23 0023 * description */ public class SmoothLinearLayoutManager extends LinearLayoutManager { public SmoothLinearLayoutManager(Context context) { super(context); } public SmoothLinearLayoutManager(Context context, int orientation, boolean reverseLayout) { super(context, orientation, reverseLayout); } @Override public void smoothScrollToPosition(RecyclerView recyclerView, RecyclerView.State state, int position) { LinearSmoothScroller linearSmoothScroller = new LinearSmoothScroller(recyclerView.getContext()) { protected float calculateSpeedPerPixel(DisplayMetrics displayMetrics) { return 0.2f; } }; linearSmoothScroller.setTargetPosition(position); startSmoothScroll(linearSmoothScroller); } }
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package com.example.bs.Home; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.support.v7.widget.LinearLayoutManager; import android.support.v7.widget.PagerSnapHelper; import android.support.v7.widget.RecyclerView; import com.example.bs.R; import java.util.ArrayList; import java.util.List; import java.util.concurrent.Executors; import java.util.concurrent.ScheduledExecutorService; import java.util.concurrent.TimeUnit; public class hom extends AppCompatActivity { private List<Integer> list = new ArrayList<>(4); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.fragment_home); list.add(R.drawable.b1); list.add(R.drawable.b2); list.add(R.drawable.b3); list.add(R.drawable.b4); BannerAdapter adapter = new BannerAdapter(this, list); final RecyclerView recyclerView = findViewById(R.id.recycler); final SmoothLinearLayoutManager layoutManager = new SmoothLinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false); recyclerView.setLayoutManager(layoutManager); recyclerView.setHasFixedSize(true); recyclerView.setAdapter(adapter); recyclerView.scrollToPosition(list.size() * 10); PagerSnapHelper snapHelper = new PagerSnapHelper(); snapHelper.attachToRecyclerView(recyclerView); final BannerIndicator bannerIndicator = findViewById(R.id.indicator); bannerIndicator.setNumber(list.size()); recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() { @Override public void onScrollStateChanged(RecyclerView recyclerView, int newState) { if (newState == RecyclerView.SCROLL_STATE_IDLE) { int i = layoutManager.findFirstVisibleItemPosition() % list.size(); bannerIndicator.setPosition(i); } } }); ScheduledExecutorService scheduledExecutorService = Executors.newScheduledThreadPool(1); scheduledExecutorService.scheduleAtFixedRate(new Runnable() { @Override public void run() { recyclerView.smoothScrollToPosition(layoutManager.findFirstVisibleItemPosition() + 1); } }, 2000, 2000, TimeUnit.MILLISECONDS); } }