自动滚动的RecyclerView(水平和垂直方向)

来源:互联网 发布:vb控件工具箱 编辑:程序博客网 时间:2024/06/11 02:41

自动滚动的RecyclerView 所以需要写一个类继承 RecyclerView  代码如下:



import android.content.Context;
import android.support.annotation.Nullable;
import android.support.v7.widget.RecyclerView;
import android.util.AttributeSet;
import android.view.MotionEvent;

import java.lang.ref.WeakReference;

public class AutoPollRecyclerView extends RecyclerView {
   private static final long TIME_AUTO_POLL = 16;
    AutoPollTask autoPollTask;
    private boolean running; //标示是否正在自动轮询
    private boolean canRun;//标示是否可以自动轮询,可在不需要的是否置false

    public AutoPollRecyclerView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        autoPollTask = new AutoPollTask(this);
    }
    static class AutoPollTask implements Runnable {
        private final WeakReference<AutoPollRecyclerView> mReference;
        //使用弱引用持有外部类引用->防止内存泄漏
        public AutoPollTask(AutoPollRecyclerView reference) {
            this.mReference = new WeakReference<AutoPollRecyclerView>(reference);
        }
        @Override
        public void run() {
            AutoPollRecyclerView recyclerView = mReference.get();
            if (recyclerView != null && recyclerView.running && recyclerView.canRun) {
                recyclerView.scrollBy(2, 2);
                recyclerView.postDelayed(recyclerView.autoPollTask, recyclerView.TIME_AUTO_POLL);
            }
        }
    }
    //开启:如果正在运行,先停止->再开启
    public void start() {
        if (running)
            stop();
        canRun = true;
        running = true;
        postDelayed(autoPollTask, TIME_AUTO_POLL);
    }
    public void stop() {
        running = false;
        removeCallbacks(autoPollTask);
    }
    @Override
    public boolean onTouchEvent(MotionEvent e) {
        switch (e.getAction()) {
            case MotionEvent.ACTION_DOWN:
                if (running)
                    stop();
                break;
            case MotionEvent.ACTION_UP:
            case MotionEvent.ACTION_CANCEL:
            case MotionEvent.ACTION_OUTSIDE:
                if (canRun)
                    start();
                break;
        }
        return super.onTouchEvent(e);//return  false,注释掉onTouchEvent()方法里面的stop和start方法,则列表自动滚动且不可触摸
    }
}


适配器的写法如下代码:


import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import java.util.List;


public class AutoPollAdapter extends RecyclerView.Adapter<AutoPollAdapter.BaseViewHolder> {
    private final Context mContext;
    private final List<String> mData;

    public AutoPollAdapter(Context context, List<String> list) {
        this.mContext = context;
        this.mData = list;
    }
    @Override
    public BaseViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(mContext).inflate(R.layout.list_item, parent, false);
        BaseViewHolder holder = new BaseViewHolder(view);
        return holder;
    }
    @Override
    public void onBindViewHolder(BaseViewHolder holder, int position) {
        String data = mData.get(position % mData.size());
        holder.content.setText(data);
    }
    @Override
    public int getItemCount() {
        return Integer.MAX_VALUE;
    }
    class BaseViewHolder extends RecyclerView.ViewHolder {
        TextView content;
        public BaseViewHolder(View itemView) {
            super(itemView);
            content = (TextView) itemView.findViewById(R.id.content);
        }
    }
}


Activity调用的写法:

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        List<String>   mData = new ArrayList<>();
        for (int i = 0; i < 30; i++) {
            mData.add("加载的第" + i + "条数据");
        }
        AutoPollRecyclerView  recyclerView = (AutoPollRecyclerView) findViewById(R.id.recyclerView);
        recyclerView.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false));//设置LinearLayoutManager.HORIZONTAL  则水平滚动
        AutoPollAdapter  mAdapter = new AutoPollAdapter(this, mData);
        recyclerView.setAdapter(mAdapter);
        recyclerView.start();//不能掉,不然不会自动滚动,根据自己的需求来
    }
}






阅读全文
0 0