android 滑动分页

it2024-10-01  20

import android.app.ListActivity;import android.os.Bundle;import android.os.Handler;import android.view.Gravity;import android.view.View;import android.view.ViewGroup;import android.widget.AbsListView;import android.widget.BaseAdapter;import android.widget.ImageView;import android.widget.LinearLayout;import android.widget.ProgressBar;import android.widget.TextView;import android.widget.AbsListView.OnScrollListener;import android.widget.LinearLayout.LayoutParams;public class Test extends ListActivity implements OnScrollListener {    Aleph0 adapter = new Aleph0();    int lastItem = 0;    int mProgressStatus = 0;    private Handler mHandler = new Handler();    ProgressBar progressBar;    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);   LinearLayout searchLayout = new LinearLayout(this);   searchLayout.setOrientation(LinearLayout.HORIZONTAL);         progressBar = new ProgressBar(this);         progressBar.setPadding(0, 0, 15, 0);         searchLayout.addView(progressBar,new LinearLayout.LayoutParams(           LinearLayout.LayoutParams.WRAP_CONTENT,           LinearLayout.LayoutParams.WRAP_CONTENT         ));         TextView textView = new TextView(this);         textView.setText("加载中...");         textView.setGravity(Gravity.CENTER_VERTICAL);         searchLayout.addView(textView,new LinearLayout.LayoutParams(           LinearLayout.LayoutParams.FILL_PARENT,           LinearLayout.LayoutParams.FILL_PARENT         ));         searchLayout.setGravity(Gravity.CENTER);         LinearLayout loadingLayout = new LinearLayout(this);         loadingLayout.addView(searchLayout,new LinearLayout.LayoutParams(           LinearLayout.LayoutParams.WRAP_CONTENT,           LinearLayout.LayoutParams.WRAP_CONTENT         ));         loadingLayout.setGravity(Gravity.CENTER);        getListView().addFooterView(loadingLayout);        // Start lengthy operation in a background thread//        new Thread(new Runnable() {//            public void run() {//                while (mProgressStatus < 100) {////                    // Update the progress bar//                    mHandler.post(new Runnable() {//                        public void run() {//                        progressBar.setProgress(mProgressStatus);//                        }//                    });//                }//            }//        }).start();        registerForContextMenu(getListView());        setListAdapter(adapter);        getListView().setOnScrollListener(this);    }    public void onScroll(AbsListView v, int firstVisibleItem, int visibleItemCount, int totalItemCount) {         lastItem = firstVisibleItem + visibleItemCount - 1 ;        System.out.println("lastItem:" + lastItem);    }    public void onScrollStateChanged(AbsListView v, int state) {    if(lastItem == adapter.count && state == OnScrollListener.SCROLL_STATE_IDLE){          adapter.count += 10;          adapter.notifyDataSetChanged();    }//        if(state == OnScrollListener.SCROLL_STATE_IDLE ) {//                adapter.count += 10;//                adapter.notifyDataSetChanged();//        }    }    class Aleph0 extends BaseAdapter {        int count = 10;        public int getCount() { return count; }        public Object getItem(int pos) { return pos; }        public long getItemId(int pos) { return pos; }        public View getView(int pos, View v, ViewGroup p) {                TextView view = new TextView(Test.this);                view.setText("entry " + pos);                view.setHeight(90);                return view;        }    }}

OnScrollListener回调分析

如果adapter中的数据量很大的时候,在加载listview时会出现卡顿的现象。这是会让用户抓狂!最好的解决办法就是先加载一定数量的数据,然后在最下方提示正在加载! 动态加载就是把放入adapter中的数据分好几次加载。在用户拖动listview时再加载一定的数据,和sina微博的客户端类似。 给listview添加OnScrollListener监听事件默认会覆盖下面两个方法: new OnScrollListener() {            boolean isLastRow = false;                    @Override            public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {                //滚动时一直回调,直到停止滚动时才停止回调。单击时回调一次。                //firstVisibleItem:当前能看见的第一个列表项ID(从0开始)                //visibleItemCount:当前能看见的列表项个数(小半个也算)                //totalItemCount:列表项共数                        //判断是否滚到最后一行                if (firstVisibleItem + visibleItemCount == totalItemCount && totalItemCount > 0) {                    isLastRow = true;                }            }            @Override            public void onScrollStateChanged(AbsListView view, int scrollState) {                //正在滚动时回调,回调2-3次,手指没抛则回调2次。scrollState = 2的这次不回调                //回调顺序如下                //第1次:scrollState = SCROLL_STATE_TOUCH_SCROLL(1) 正在滚动                //第2次:scrollState = SCROLL_STATE_FLING(2) 手指做了抛的动作(手指离开屏幕前,用力滑了一下)                //第3次:scrollState = SCROLL_STATE_IDLE(0) 停止滚动                                       //当屏幕停止滚动时为0;当屏幕滚动且用户使用的触碰或手指还在屏幕上时为1;              //由于用户的操作,屏幕产生惯性滑动时为2                      //当滚到最后一行且停止滚动时,执行加载                if (isLastRow && scrollState == AbsListView.OnScrollListener.SCROLL_STATE_IDLE) {                    //加载元素                    ......                            isLastRow = false;                }            }        }

转载于:https://www.cnblogs.com/SZ2015/p/4640558.html

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