android 滑动加载数据

最新推荐文章于 2024-03-23 12:52:30 发布

最新推荐文章于 2024-03-23 12:52:30 发布 · 96 阅读

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本文介绍了一种在Android应用中实现无限滚动列表的方法。通过自定义Adapter并结合使用OnScrollListener监听滚动状态，实现在接近列表底部时自动加载更多数据的功能。同时提供了一个使用按钮手动触发加载更多的替代方案。

package com.ScrollListView;

import android.app.ListActivity;
import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.BaseAdapter;
import android.widget.LinearLayout;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.AbsListView.OnScrollListener;

public class EndLessActivity extends ListActivity implements OnScrollListener{

Aleph0adapter = new Aleph0();
int mProgressStatus = 0 ;
ProgressBarprogressBar;
protected void onCreate(BundlesavedInstanceState){
super .onCreate(savedInstanceState);
LinearLayoutsearchLayout = 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
));
TextViewtextView = 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);
LinearLayoutloadingLayout = new LinearLayout( this );
loadingLayout.addView(searchLayout, new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.WRAP_CONTENT,
LinearLayout.LayoutParams.WRAP_CONTENT
));
loadingLayout.setGravity(Gravity.CENTER);
getListView().addFooterView(loadingLayout);

setListAdapter(adapter);
getListView().setOnScrollListener( this );
}

public void onScroll(AbsListViewview,
int firstVisible, int visibleCount, int totalCount){

boolean loadMore = /* maybeaddapadding */
firstVisible + visibleCount >= totalCount;

if (loadMore){
adapter.count += visibleCount; // oranyotheramount
adapter.notifyDataSetChanged();
}
}

public void onScrollStateChanged(AbsListViewv, int s){}

class Aleph0 extends BaseAdapter{
int count = 40 ; /* startingamount */

public int getCount(){ return count;}
public ObjectgetItem( int pos){ return pos;}
public long getItemId( int pos){ return pos;}

public ViewgetView( int pos,Viewv,ViewGroupp){
TextViewview = new TextView(EndLessActivity. this );
view.setText( " entry " + pos);
return view;
}
}

}

listview下部是按钮控制：

package com.ScrollListView;

import android.app.ListActivity;
import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.AbsListView.OnScrollListener;

public class EndLessActivity extends ListActivity{

Aleph0adapter = new Aleph0();
int mProgressStatus = 0 ;

protected void onCreate(BundlesavedInstanceState){
super .onCreate(savedInstanceState);
LinearLayoutsearchLayout = new LinearLayout( this );
searchLayout.setOrientation(LinearLayout.HORIZONTAL);

ButtontextView = new Button( 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);
LinearLayoutloadingLayout = new LinearLayout( this );
loadingLayout.addView(searchLayout, new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.WRAP_CONTENT,
LinearLayout.LayoutParams.WRAP_CONTENT
));
loadingLayout.setGravity(Gravity.CENTER);
getListView().addFooterView(loadingLayout);
textView.setOnClickListener( new Button.OnClickListener()
{@Override
public void onClick(Viewv)
{
adapter.count += 10 ;
adapter.notifyDataSetChanged();
}
});

setListAdapter(adapter);
// getListView().setOnScrollListener(this);
}

/* publicvoidonScroll(AbsListViewview,
intfirstVisible,intvisibleCount,inttotalCount){

booleanloadMore=
firstVisible+visibleCount>=totalCount;

if(loadMore){
adapter.count+=visibleCount;
adapter.notifyDataSetChanged();
}
} */

public void onScrollStateChanged(AbsListViewv, int s){}

class Aleph0 extends BaseAdapter{
int count = 40 ; /* startingamount */

public int getCount(){ return count;}
public ObjectgetItem( int pos){ return pos;}
public long getItemId( int pos){ return pos;}

public ViewgetView( int pos,Viewv,ViewGroupp){
TextViewview = new TextView(EndLessActivity. this );
view.setText( " entry " + pos);
return view;
}
}

}