listview下拉刷新

最新推荐文章于 2025-05-23 10:22:46 发布

转载最新推荐文章于 2025-05-23 10:22:46 发布 · 428 阅读

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本文介绍了一种在Android中实现ListView下拉刷新功能的方法。通过自定义ReFlashListView类，结合触摸事件监听和动画效果，实现了流畅的下拉刷新体验。文章详细解释了如何根据不同的状态调整UI显示，并提供了完整的代码示例。

package com.imooc.listviewfrashdemo1;

import java.text.SimpleDateFormat;
import java.util.Date;

import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.RotateAnimation;
import android.widget.AbsListView;
import android.widget.AbsListView.OnScrollListener;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.TextView;

import com.example.listviewfrashdemo1.R;

public class ReFlashListView extends ListView implements OnScrollListener {
    View header;// 顶部布局文件；
    int headerHeight;// 顶部布局文件的高度；
    int firstVisibleItem;// 当前第一个可见的item的位置；
    int scrollState;// listview 当前滚动状态；
    boolean isRemark;// 标记，当前是在listview最顶端摁下的；
    int startY;// 摁下时的Y值；

    int state;// 当前的状态；
    final int NONE = 0;// 正常状态；
    final int PULL = 1;// 提示下拉状态；
    final int RELESE = 2;// 提示释放状态；
    final int REFLASHING = 3;// 刷新状态；
    IReflashListener iReflashListener;//刷新数据的接口
    public ReFlashListView(Context context) {
        super(context);
        // TODO Auto-generated constructor stub
        initView(context);
    }

    public ReFlashListView(Context context, AttributeSet attrs) {
        super(context, attrs);
        // TODO Auto-generated constructor stub
        initView(context);
    }

    public ReFlashListView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        // TODO Auto-generated constructor stub
        initView(context);
    }

    /**
     * 初始化界面，添加顶部布局文件到 listview
     * 
     * @param context
     */
    private void initView(Context context) {
        LayoutInflater inflater = LayoutInflater.from(context);
        header = inflater.inflate(R.layout.header_layout, null);
        measureView(header);
        headerHeight = header.getMeasuredHeight();
        Log.i("tag", "headerHeight = " + headerHeight);
        topPadding(-headerHeight);
        this.addHeaderView(header);
        this.setOnScrollListener(this);
    }

    /**
     * 通知父布局，占用的宽，高；
     * 
     * @param view
     */
    private void measureView(View view) {
        ViewGroup.LayoutParams p = view.getLayoutParams();
        if (p == null) {
            p = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
                    ViewGroup.LayoutParams.WRAP_CONTENT);
        }
        int width = ViewGroup.getChildMeasureSpec(0, 0, p.width);
        int height;
        int tempHeight = p.height;
        if (tempHeight > 0) {
            height = MeasureSpec.makeMeasureSpec(tempHeight,
                    MeasureSpec.EXACTLY);
        } else {
            height = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
        }
        view.measure(width, height);
    }

    /**
     * 设置header 布局 上边距；
     * 
     * @param topPadding
     */
    private void topPadding(int topPadding) {
        header.setPadding(header.getPaddingLeft(), topPadding,
                header.getPaddingRight(), header.getPaddingBottom());
        header.invalidate();
    }

    @Override
    public void onScroll(AbsListView view, int firstVisibleItem,
            int visibleItemCount, int totalItemCount) {
        // TODO Auto-generated method stub
        this.firstVisibleItem = firstVisibleItem;
    }

    @Override
    public void onScrollStateChanged(AbsListView view, int scrollState) {
        // TODO Auto-generated method stub
        this.scrollState = scrollState;
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        // TODO Auto-generated method stub
        switch (ev.getAction()) {
        case MotionEvent.ACTION_DOWN:
            if (firstVisibleItem == 0) {
                isRemark = true;
                startY = (int) ev.getY();
            }
            break;

        case MotionEvent.ACTION_MOVE:
            onMove(ev);
            break;
        case MotionEvent.ACTION_UP:
            if (state == RELESE) {
                state = REFLASHING;
                // 加载最新数据；
                reflashViewByState();
                iReflashListener.onReflash();
            } else if (state == PULL) {
                state = NONE;
                isRemark = false;
                reflashViewByState();
            }
            break;
        }
        return super.onTouchEvent(ev);
    }

    /**
     * 判断移动过程操作；
     * 
     * @param ev
     */
    private void onMove(MotionEvent ev) {
        if (!isRemark) {
            return;
        }
        int tempY = (int) ev.getY();
        int space = tempY - startY;
        int topPadding = space - headerHeight;
        switch (state) {
        case NONE:
            if (space > 0) {
                state = PULL;
                reflashViewByState();
            }
            break;
        case PULL:
            topPadding(topPadding);
            if (space > headerHeight + 30
                    && scrollState == SCROLL_STATE_TOUCH_SCROLL) {
                state = RELESE;
                reflashViewByState();
            }
            break;
        case RELESE:
            topPadding(topPadding);
            if (space < headerHeight + 30) {
                state = PULL;
                reflashViewByState();
            } else if (space <= 0) {
                state = NONE;
                isRemark = false;
                reflashViewByState();
            }
            break;
        }
    }

    /**
     * 根据当前状态，改变界面显示；
     */
    private void reflashViewByState() {
        TextView tip = (TextView) header.findViewById(R.id.tip);
        ImageView arrow = (ImageView) header.findViewById(R.id.arrow);
        ProgressBar progress = (ProgressBar) header.findViewById(R.id.progress);
        RotateAnimation anim = new RotateAnimation(0, 180,
                RotateAnimation.RELATIVE_TO_SELF, 0.5f,
                RotateAnimation.RELATIVE_TO_SELF, 0.5f);
        anim.setDuration(500);
        anim.setFillAfter(true);
        RotateAnimation anim1 = new RotateAnimation(180, 0,
                RotateAnimation.RELATIVE_TO_SELF, 0.5f,
                RotateAnimation.RELATIVE_TO_SELF, 0.5f);
        anim1.setDuration(500);
        anim1.setFillAfter(true);
        switch (state) {
        case NONE:
            arrow.clearAnimation();
            topPadding(-headerHeight);
            break;

        case PULL:
            arrow.setVisibility(View.VISIBLE);
            progress.setVisibility(View.GONE);
            tip.setText("下拉可以刷新！");
            arrow.clearAnimation();
            arrow.setAnimation(anim1);
            break;
        case RELESE:
            arrow.setVisibility(View.VISIBLE);
            progress.setVisibility(View.GONE);
            tip.setText("松开可以刷新！");
            arrow.clearAnimation();
            arrow.setAnimation(anim);
            break;
        case REFLASHING:
            topPadding(50);
            arrow.setVisibility(View.GONE);
            progress.setVisibility(View.VISIBLE);
            tip.setText("正在刷新...");
            arrow.clearAnimation();
            break;
        }
    }

    /**
     * 获取完数据；
     */
    public void reflashComplete() {
        state = NONE;
        isRemark = false;
        reflashViewByState();
        TextView lastupdatetime = (TextView) header
                .findViewById(R.id.lastupdate_time);
        SimpleDateFormat format = new SimpleDateFormat("yyyy年MM月dd日 hh:mm:ss");
        Date date = new Date(System.currentTimeMillis());
        String time = format.format(date);
        lastupdatetime.setText(time);
    }

    public void setInterface(IReflashListener iReflashListener){
        this.iReflashListener = iReflashListener;
    }
    /**
     * 刷新数据接口
     * @author Administrator
     */
    public interface IReflashListener{
        public void onReflash();
    }
}

package com.imooc.listviewfrashdemo1;

import java.util.ArrayList;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;

import com.example.listviewfrashdemo1.R;
import com.imooc.listviewfrashdemo1.ReFlashListView.IReflashListener;

public class MainActivity extends Activity implements IReflashListener{
    ArrayList<ApkEntity> apk_list;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setData();
        showList(apk_list);
    }

    MyAdapter adapter;
    ReFlashListView listview;
    private void showList(ArrayList<ApkEntity> apk_list) {
        if (adapter == null) {
            listview = (ReFlashListView) findViewById(R.id.listview);
            listview.setInterface(this);
            adapter = new MyAdapter(this, apk_list);
            listview.setAdapter(adapter);
        } else {
            adapter.onDateChange(apk_list);
        }
    }

    private void setData() {
        apk_list = new ArrayList<ApkEntity>();
        for (int i = 0; i < 10; i++) {
            ApkEntity entity = new ApkEntity();
            entity.setName("默认数据");
            entity.setDes("这是一个神奇的应用");
            entity.setInfo("50w用户");
            apk_list.add(entity);
        }
    }

    private void setReflashData() {
        for (int i = 0; i < 2; i++) {
            ApkEntity entity = new ApkEntity();
            entity.setName("刷新数据");
            entity.setDes("这是一个神奇的应用");
            entity.setInfo("50w用户");
            apk_list.add(0,entity);
        }
    }
    @Override
    public void onReflash() {
        // TODO Auto-generated method stub\
        Handler handler = new Handler();
        handler.postDelayed(new Runnable() {

            @Override
            public void run() {
                // TODO Auto-generated method stub
                //获取最新数据
                setReflashData();
                //通知界面显示
                showList(apk_list);
                //通知listview 刷新数据完毕；
                listview.reflashComplete();
            }
        }, 2000);

    }
}

package com.imooc.listviewfrashdemo1;

import java.util.ArrayList;

import com.example.listviewfrashdemo1.R;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;

public class MyAdapter extends BaseAdapter {
    ArrayList<ApkEntity> apk_list;
    LayoutInflater inflater;

    public MyAdapter(Context context, ArrayList<ApkEntity> apk_list) {
        this.apk_list = apk_list;
        this.inflater = LayoutInflater.from(context);
    }

    public void onDateChange(ArrayList<ApkEntity> apk_list) {
        this.apk_list = apk_list;
        this.notifyDataSetChanged();
    }

    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        return apk_list.size();
    }

    @Override
    public Object getItem(int position) {
        // TODO Auto-generated method stub
        return apk_list.get(position);
    }

    @Override
    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub
        ApkEntity entity = apk_list.get(position);
        ViewHolder holder;
        if (convertView == null) {
            holder = new ViewHolder();
            convertView = inflater.inflate(R.layout.item_layout, null);
            holder.name_tv = (TextView) convertView
                    .findViewById(R.id.item3_apkname);
            holder.des_tv = (TextView) convertView
                    .findViewById(R.id.item3_apkdes);
            holder.info_tv = (TextView) convertView
                    .findViewById(R.id.item3_apkinfo);
            convertView.setTag(holder);
        }else{
            holder = (ViewHolder) convertView.getTag();
        }
        holder.name_tv.setText(entity.getName());
        holder.des_tv.setText(entity.getDes());
        holder.info_tv.setText(entity.getInfo());
        return convertView;
    }

    class ViewHolder {
        TextView name_tv;
        TextView des_tv;
        TextView info_tv;
    }
}