android上拉下拉加载更多数据
时间:2022-04-25
本文章向大家介绍android上拉下拉加载更多数据，主要内容包括其使用实例、应用技巧、基本知识点总结和需要注意事项，具有一定的参考价值，需要的朋友可以参考一下。
最近项目中用到了ListView的下拉刷新的功能，总结了一下前辈们的代码，单独抽取出来写了一个demo作为示例。
效果图
下拉刷新：
加载更多：
CustomListView.java
package com.example.uitest.view;
import java.util.Date;
import com.example.uitest.R;
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.LinearInterpolator;
import android.view.animation.RotateAnimation;
import android.widget.AbsListView;
import android.widget.AbsListView.OnScrollListener;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.TextView;
/**
* ListView下拉刷新
*
*/
public class CustomListView extends ListView implements OnScrollListener {
private final static int RELEASE_To_REFRESH = 0;
private final static int PULL_To_REFRESH = 1;
private final static int REFRESHING = 2;
private final static int DONE = 3;
private final static int LOADING = 4;
// 实际的padding的距离与界面上偏移距离的比例
private final static int RATIO = 3;
private LayoutInflater inflater;
private LinearLayout headView;
private TextView tipsTextview;
private TextView lastUpdatedTextView;
private ImageView arrowImageView;
private ProgressBar progressBar;
private RotateAnimation animation;
private RotateAnimation reverseAnimation;
// 用于保证startY的值在一个完整的touch事件中只被记录一次
private boolean isRecored;
private int headContentWidth;
private int headContentHeight;
private int startY;
private int firstItemIndex;
private int state;
private boolean isBack;
private OnRefreshListener refreshListener;
private OnLoadListener loadListener;
private boolean isRefreshable;
private ProgressBar moreProgressBar;
private TextView loadMoreView;
private View moreView;
public CustomListView(Context context) {
super(context);
init(context);
}
public CustomListView(Context context, AttributeSet attrs) {
super(context, attrs);
init(context);
}
private void init(Context context) {
setCacheColorHint(context.getResources().getColor(R.color.transparent));
inflater = LayoutInflater.from(context);
headView = (LinearLayout) inflater.inflate(R.layout.head, null);
arrowImageView = (ImageView) headView.findViewById(R.id.head_arrowImageView);
arrowImageView.setMinimumWidth(70);
arrowImageView.setMinimumHeight(50);
progressBar = (ProgressBar) headView.findViewById(R.id.head_progressBar);
tipsTextview = (TextView) headView.findViewById(R.id.head_tipsTextView);
lastUpdatedTextView = (TextView) headView.findViewById(R.id.head_lastUpdatedTextView);
measureView(headView);
headContentHeight = headView.getMeasuredHeight();
headContentWidth = headView.getMeasuredWidth();
headView.setPadding(0, -1 * headContentHeight, 0, 0);
headView.invalidate();
Log.v("size", "width:" + headContentWidth + " height:" + headContentHeight);
addHeaderView(headView, null, false);
setOnScrollListener(this);
animation = new RotateAnimation(0, -180, RotateAnimation.RELATIVE_TO_SELF, 0.5f, RotateAnimation.RELATIVE_TO_SELF, 0.5f);
animation.setInterpolator(new LinearInterpolator());
animation.setDuration(250);
animation.setFillAfter(true);
reverseAnimation = new RotateAnimation(-180, 0, RotateAnimation.RELATIVE_TO_SELF, 0.5f, RotateAnimation.RELATIVE_TO_SELF, 0.5f);
reverseAnimation.setInterpolator(new LinearInterpolator());
reverseAnimation.setDuration(200);
reverseAnimation.setFillAfter(true);
state = DONE;
isRefreshable = false;
moreView = LayoutInflater.from(context).inflate(R.layout.listfooter_more, null);
moreView.setVisibility(View.VISIBLE);
moreProgressBar = (ProgressBar) moreView.findViewById(R.id.pull_to_refresh_progress);
loadMoreView = (TextView) moreView.findViewById(R.id.load_more);
moreView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
onLoad();
}
});
addFooterView(moreView);
}
public void onScroll(AbsListView arg0, int firstVisiableItem, int arg2, int arg3) {
firstItemIndex = firstVisiableItem;
}
public void onScrollStateChanged(AbsListView arg0, int arg1) {
}
public boolean onTouchEvent(MotionEvent event) {
if (isRefreshable) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
if (firstItemIndex == 0 && !isRecored) {
isRecored = true;
startY = (int) event.getY();
}
break;
case MotionEvent.ACTION_UP:
if (state != REFRESHING && state != LOADING) {
if (state == DONE) {
}
if (state == PULL_To_REFRESH) {
state = DONE;
changeHeaderViewByState();
}
if (state == RELEASE_To_REFRESH) {
state = REFRESHING;
changeHeaderViewByState();
onRefresh();
}
}
isRecored = false;
isBack = false;
break;
case MotionEvent.ACTION_MOVE:
int tempY = (int) event.getY();
if (!isRecored && firstItemIndex == 0) {
isRecored = true;
startY = tempY;
}
if (state != REFRESHING && isRecored && state != LOADING) {
// 保证在设置padding的过程中，当前的位置一直是在head，否则如果当列表超出屏幕的话，当在上推的时候，列表会同时进行滚动
// 可以松手去刷新了
if (state == RELEASE_To_REFRESH) {
setSelection(0);
// 往上推了，推到了屏幕足够掩盖head的程度，但是还没有推到全部掩盖的地步
if (((tempY - startY) / RATIO < headContentHeight) && (tempY - startY) > 0) {
state = PULL_To_REFRESH;
changeHeaderViewByState();
}
// 一下子推到顶了
else if (tempY - startY <= 0) {
state = DONE;
changeHeaderViewByState();
}
// 往下拉了，或者还没有上推到屏幕顶部掩盖head的地步
}
// 还没有到达显示松开刷新的时候,DONE或者是PULL_To_REFRESH状态
if (state == PULL_To_REFRESH) {
setSelection(0);
// 下拉到可以进入RELEASE_TO_REFRESH的状态
if ((tempY - startY) / RATIO >= headContentHeight) {
state = RELEASE_To_REFRESH;
isBack = true;
changeHeaderViewByState();
}
else if (tempY - startY <= 0) {
state = DONE;
changeHeaderViewByState();
}
}
if (state == DONE) {
if (tempY - startY > 0) {
state = PULL_To_REFRESH;
changeHeaderViewByState();
}
}
if (state == PULL_To_REFRESH) {
headView.setPadding(0, -1 * headContentHeight + (tempY - startY) / RATIO, 0, 0);
}
if (state == RELEASE_To_REFRESH) {
headView.setPadding(0, (tempY - startY) / RATIO - headContentHeight, 0, 0);
}
}
break;
}
}
return super.onTouchEvent(event);
}
// 当状态改变时候，调用该方法，以更新界面
private void changeHeaderViewByState() {
switch (state) {
case RELEASE_To_REFRESH:
arrowImageView.setVisibility(View.VISIBLE);
progressBar.setVisibility(View.GONE);
tipsTextview.setVisibility(View.VISIBLE);
lastUpdatedTextView.setVisibility(View.VISIBLE);
arrowImageView.clearAnimation();
arrowImageView.startAnimation(animation);
tipsTextview.setText("松开刷新");
break;
case PULL_To_REFRESH:
progressBar.setVisibility(View.GONE);
tipsTextview.setVisibility(View.VISIBLE);
lastUpdatedTextView.setVisibility(View.VISIBLE);
arrowImageView.clearAnimation();
arrowImageView.setVisibility(View.VISIBLE);
// 是由RELEASE_To_REFRESH状态转变来的
if (isBack) {
isBack = false;
arrowImageView.clearAnimation();
arrowImageView.startAnimation(reverseAnimation);
tipsTextview.setText("下拉刷新");
} else {
tipsTextview.setText("下拉刷新");
}
break;
case REFRESHING:
headView.setPadding(0, 0, 0, 0);
progressBar.setVisibility(View.VISIBLE);
arrowImageView.clearAnimation();
arrowImageView.setVisibility(View.GONE);
tipsTextview.setText("正在刷新...");
lastUpdatedTextView.setVisibility(View.VISIBLE);
break;
case DONE:
headView.setPadding(0, -1 * headContentHeight, 0, 0);
progressBar.setVisibility(View.GONE);
arrowImageView.clearAnimation();
arrowImageView.setImageResource(R.drawable.arrow);
tipsTextview.setText("下拉刷新");
lastUpdatedTextView.setVisibility(View.VISIBLE);
break;
}
}
public void setonRefreshListener(OnRefreshListener refreshListener) {
this.refreshListener = refreshListener;
isRefreshable = true;
}
public void setonLoadListener(OnLoadListener loadListener) {
this.loadListener = loadListener;
}
public interface OnRefreshListener {
public void onRefresh();
}
public interface OnLoadListener {
public void onLoad();
}
@SuppressWarnings("deprecation")
public void onRefreshComplete() {
state = DONE;
lastUpdatedTextView.setText("最近更新:" + new Date().toLocaleString());
changeHeaderViewByState();
}
private void onLoad() {
if (loadListener != null) {
moreProgressBar.setVisibility(View.VISIBLE);
loadMoreView.setText(getContext().getString(R.string.load_more));
loadListener.onLoad();
}
}
public void onLoadComplete() {
// moreView.setVisibility(View.GONE);
moreProgressBar.setVisibility(View.GONE);
loadMoreView.setText(getContext().getString(R.string.more_data));
}
private void onRefresh() {
if (refreshListener != null) {
refreshListener.onRefresh();
}
}
private void measureView(View child) {
ViewGroup.LayoutParams p = child.getLayoutParams();
if (p == null) {
p = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
}
int childWidthSpec = ViewGroup.getChildMeasureSpec(0, 0 + 0, p.width);
int lpHeight = p.height;
int childHeightSpec;
if (lpHeight > 0) {
childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY);
} else {
childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
}
child.measure(childWidthSpec, childHeightSpec);
}
@SuppressWarnings("deprecation")
public void setAdapter(BaseAdapter adapter) {
lastUpdatedTextView.setText("最近更新:" + new Date().toLocaleString());
super.setAdapter(adapter);
}
} 在 CustomListView 中有2个回调接口，OnRefreshListener 和 OnLoadListener ，分别对应 下拉和点击加载更多 时候的回调函数。在下拉刷新完成之后要调用 mListView.onRefreshComplete(); 来隐藏掉 头部，调用 mListView.onLoadComplete(); 隐藏掉 底部的加载view。
header.xml
<?xml version="1.0" encoding="utf-8"?>
<!-- ListView的头部 -->
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >
<!-- 内容 -->
<RelativeLayout
android:id="@+id/head_contentLayout"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingLeft="30dp" >
<!-- 箭头图像、进度条 -->
<FrameLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_centerVertical="true" >
<!-- 箭头 -->
<ImageView
android:id="@+id/head_arrowImageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:contentDescription="@string/app_name"
android:src="@drawable/arrow" />
<!-- 进度条 -->
<ProgressBar
android:id="@+id/head_progressBar"
style="?android:attr/progressBarStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:indeterminateDrawable="@drawable/progressbar_bg"
android:visibility="gone" />
</FrameLayout>
<!-- 提示、最近更新 -->
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:gravity="center_horizontal"
android:orientation="vertical" >
<!-- 提示 -->
<TextView
android:id="@+id/head_tipsTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/pull_to_refresh_pull_label"
android:textColor="@color/pull_refresh_textview"
android:textSize="20sp" />
<!-- 最近更新 -->
<TextView
android:id="@+id/head_lastUpdatedTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/pull_to_refresh_refresh_lasttime"
android:textColor="@color/gold"
android:textSize="10sp" />
</LinearLayout>
</RelativeLayout>
</LinearLayout> listfooter_more.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center_horizontal"
android:orientation="horizontal"
android:padding="15dp"
>
<ProgressBar
android:id="@+id/pull_to_refresh_progress"
style="@android:style/Widget.ProgressBar.Small.Inverse"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
android:indeterminate="true"
android:visibility="gone" >
</ProgressBar>
<TextView
android:id="@+id/load_more"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="10.0dp"
android:gravity="center"
android:text="@string/more_data"
android:textColor="@color/black" >
</TextView>
</LinearLayout> MainActivity.java
package com.example.uitest;
import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.content.Context;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;
import com.example.uitest.model.AppInfo;
import com.example.uitest.view.CustomListView;
import com.example.uitest.view.CustomListView.OnLoadListener;
import com.example.uitest.view.CustomListView.OnRefreshListener;
public class MainActivity extends Activity {
private static final String TAG = MainActivity.class.getSimpleName();
private static final int LOAD_DATA_FINISH = 10;
private static final int REFRESH_DATA_FINISH = 11;
private List<AppInfo> mList = new ArrayList<AppInfo>();
private CustomListAdapter mAdapter;
private CustomListView mListView;
private int count = 10;
private Handler handler = new Handler(){
public void handleMessage(android.os.Message msg) {
switch (msg.what) {
case REFRESH_DATA_FINISH:
if(mAdapter!=null){
mAdapter.notifyDataSetChanged();
}
mListView.onRefreshComplete(); //下拉刷新完成
break;
case LOAD_DATA_FINISH:
if(mAdapter!=null){
mAdapter.notifyDataSetChanged();
}
mListView.onLoadComplete(); //加载更多完成
break;
default:
break;
}
};
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
buildAppData();
mAdapter = new CustomListAdapter(this);
mListView = (CustomListView) findViewById(R.id.mListView);
mListView.setAdapter(mAdapter);
mListView.setonRefreshListener(new OnRefreshListener() {
@Override
public void onRefresh() {
//TODO 下拉刷新
Log.e(TAG, "onRefresh");
loadData(0);
}
});
mListView.setonLoadListener(new OnLoadListener() {
@Override
public void onLoad() {
//TODO 加载更多
Log.e(TAG, "onLoad");
loadData(1);
}
});
mListView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
Log.e(TAG, "click position:" + position);
}
});
}
public void loadData(final int type){
new Thread(){
@Override
public void run() {
for(int i=count;i<count+10;i++){
AppInfo ai = new AppInfo();
ai.setAppIcon(BitmapFactory.decodeResource(getResources(),
R.drawable.ic_launcher));
ai.setAppName("应用Demo_" + i);
ai.setAppVer("版本: " + (i % 10 + 1) + "." + (i % 8 + 2) + "."
+ (i % 6 + 3));
ai.setAppSize("大小: " + i * 10 + "MB");
mList.add(ai);
}
count += 10;
try {
Thread.sleep(300);
} catch (InterruptedException e) {
e.printStackTrace();
}
if(type==0){ //下拉刷新
// Collections.reverse(mList); //逆序
handler.sendEmptyMessage(REFRESH_DATA_FINISH);
}else if(type==1){
handler.sendEmptyMessage(LOAD_DATA_FINISH);
}
}
}.start();
}
/**
* 初始化应用数据
*/
private void buildAppData() {
for (int i = 0; i < 10; i++) {
AppInfo ai = new AppInfo();
ai.setAppIcon(BitmapFactory.decodeResource(getResources(),
R.drawable.ic_launcher));
ai.setAppName("应用Demo_" + i);
ai.setAppVer("版本: " + (i % 10 + 1) + "." + (i % 8 + 2) + "."
+ (i % 6 + 3));
ai.setAppSize("大小: " + i * 10 + "MB");
mList.add(ai);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
public class CustomListAdapter extends BaseAdapter {
private LayoutInflater mInflater;
public CustomListAdapter(Context context) {
mInflater = LayoutInflater.from(context);
}
@Override
public int getCount() {
return mList.size();
}
@Override
public Object getItem(int arg0) {
return mList.get(arg0);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if (getCount() == 0) {
return null;
}
ViewHolder holder = null;
if (convertView == null) {
convertView = mInflater.inflate(R.layout.list_item, null);
holder = new ViewHolder();
holder.ivImage = (ImageView) convertView
.findViewById(R.id.ivIcon);
holder.tvName = (TextView) convertView
.findViewById(R.id.tvName);
holder.tvVer = (TextView) convertView.findViewById(R.id.tvVer);
holder.tvSize = (TextView) convertView
.findViewById(R.id.tvSize);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
AppInfo ai = mList.get(position);
holder.ivImage.setImageBitmap(ai.getAppIcon());
holder.tvName.setText(ai.getAppName());
holder.tvVer.setText(ai.getAppVer());
holder.tvSize.setText(ai.getAppSize());
return convertView;
}
}
public static class ViewHolder {
private ImageView ivImage;
private TextView tvName;
private TextView tvVer;
private TextView tvSize;
}
} list_item.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<ImageView
android:id="@+id/ivIcon"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:contentDescription="@string/image_desc"
android:src="@drawable/ic_launcher" />
<LinearLayout
android:id="@+id/appInfo"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="5dip"
android:layout_toRightOf="@id/ivIcon"
android:orientation="vertical" >
<TextView
android:id="@+id/tvName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/name"
android:textColor="#000000"
android:textSize="16sp" />
<TextView
android:id="@+id/tvVer"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/ver"
android:textColor="#666666"
android:textSize="13sp" />
<TextView
android:id="@+id/tvSize"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/size"
android:textColor="#666666"
android:textSize="13sp" />
</LinearLayout>
<Button
android:id="@+id/btnClick"
android:layout_width="80dip"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_centerVertical="true"
android:focusable="false"
android:text="@string/mgr"
android:textColor="#000000"
android:textSize="16sp" />
</RelativeLayout> 工程下载地址：http://download.csdn.net/detail/fx_sky/5646017
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