一.概述
Android 下拉刷新几乎是每个应用都必带的功能, 并且现在下拉刷新第三方库也越来越多了,很方便就能实现该功能, 下面我介绍一下 自己常用的几个方法.
二.例子
第一种方式:就是集成ListView实现自定义控件完成上下拉刷新
public class PullToRefreshListView extends ListView implements OnScrollListener, OnClickListener {
/**
* 下拉状态
*/
private static final int PULL_TO_REFRESH = 1; //下拉-默认为初始状态 准备下拉刷新
private static final int RELEASE_TO_REFRESH = 2; //释放刷新
private static final int REFRESHING = 3; //正在刷新
private static final String TAG = "PullRefreshListView";
private OnRefreshListener mOnRefreshListener;
/**
* 组件滑动监听器 scroll 当view在进行下拉滑动的时候，判断滑动的距离，
* 如果达到可以进行刷新的临界点时候，回调当前接口中的方法
* Listener that will receive notifications every time the list scrolls.
*/
private OnScrollListener mOnScrollListener;
//下拉刷新的的头部view
private LinearLayout mRefreshView;
private ImageView mRefreshViewImage;
private ProgressBar mRefreshViewProgress;
private TextView mRefreshViewText;
private TextView mRefreshViewLastUpdated;
private int mRefreshState;
private int mCurrentScrollState;
private RotateAnimation mFlipAnimation;
private RotateAnimation mReverseFlipAnimation;
private int mRefreshViewHeight;
private int mRefreshOriginalTopPadding;
private int mLastMotionY;
public PullToRefreshListView(Context context) {
super(context);
init(context);
}
public PullToRefreshListView(Context context, AttributeSet attrs) {
super(context, attrs);
init(context);
}
private void init(Context context) {
mFlipAnimation = new RotateAnimation(0, -180,
RotateAnimation.RELATIVE_TO_SELF, 0.5f,
RotateAnimation.RELATIVE_TO_SELF, 0.5f);
mFlipAnimation.setInterpolator(new LinearInterpolator());
mFlipAnimation.setDuration(250);
mFlipAnimation.setFillAfter(true);
mReverseFlipAnimation = new RotateAnimation(-180, 0,
RotateAnimation.RELATIVE_TO_SELF, 0.5f,
RotateAnimation.RELATIVE_TO_SELF, 0.5f);
mReverseFlipAnimation.setInterpolator(new LinearInterpolator());
mReverseFlipAnimation.setDuration(250);
mReverseFlipAnimation.setFillAfter(true);
mRefreshView = (LinearLayout) View.inflate(context, R.layout.pull_to_refresh_header, null);
mRefreshViewText = (TextView) mRefreshView.findViewById(R.id.pull_to_refresh_text);
mRefreshViewImage = (ImageView) mRefreshView.findViewById(R.id.pull_to_refresh_image);
mRefreshViewProgress = (ProgressBar) mRefreshView.findViewById(R.id.pull_to_refresh_progress);
mRefreshViewLastUpdated = (TextView) mRefreshView.findViewById(R.id.pull_to_refresh_updated_at);
mRefreshState = PULL_TO_REFRESH;
mRefreshViewImage.setMinimumHeight(50); //设置下拉最小的高度为50
setFadingEdgeLength(0);
setHeaderDividersEnabled(false);
//把refreshview加入到listview的头部
addHeaderView(mRefreshView);
super.setOnScrollListener(this);
mRefreshView.setOnClickListener(this);
mRefreshView.measure(MeasureSpec.UNSPECIFIED, MeasureSpec.UNSPECIFIED);
mRefreshViewHeight = mRefreshView.getMeasuredHeight();
mRefreshOriginalTopPadding = -mRefreshViewHeight;
resetHeaderPadding();
}
/**
* Set the listener that will receive notifications every time the list scrolls.
*
* @param l The scroll listener.
*/
@Override
public void setOnScrollListener(OnScrollListener l) {
mOnScrollListener = l;
}
/**
* 注册listview下拉刷新回到接口
* Register a callback to be invoked when this list should be refreshed.
*
* @param onRefreshListener The callback to run.
*/
public void setOnRefreshListener(OnRefreshListener onRefreshListener) {
mOnRefreshListener = onRefreshListener;
}
/**
* 进行设置设置上一次更新的时候
*
* Set a text to represent when the list was last updated.
* @param lastUpdated Last updated at.
*/
public void setLastUpdated(CharSequence lastUpdated) {
if (lastUpdated != null) {
mRefreshViewLastUpdated.setVisibility(View.VISIBLE);
mRefreshViewLastUpdated.setText(lastUpdated);
} else {
mRefreshViewLastUpdated.setVisibility(View.GONE);
}
}
/**
* touch事件处理
* @param event
* @return
*/
@Override
public boolean onTouchEvent(MotionEvent event) {
final int y = (int) event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
mLastMotionY = y;
break;
case MotionEvent.ACTION_MOVE:
int offsetY = (int) event.getY();
int deltY = Math.round(offsetY - mLastMotionY);
mLastMotionY = offsetY;
if (getFirstVisiblePosition() == 0 && mRefreshState != REFRESHING) {
deltY = deltY / 2;
mRefreshOriginalTopPadding += deltY;
if (mRefreshOriginalTopPadding < -mRefreshViewHeight) {
mRefreshOriginalTopPadding = -mRefreshViewHeight;
}
resetHeaderPadding();
}
break;
case MotionEvent.ACTION_UP:
//当手指抬开得时候 进行判断下拉的距离 ，如果>=临界值，那么进行刷洗，否则回归原位
if (!isVerticalScrollBarEnabled()) {
setVerticalScrollBarEnabled(true);
}
if (getFirstVisiblePosition() == 0 && mRefreshState != REFRESHING) {
if (mRefreshView.getBottom() >= mRefreshViewHeight
&& mRefreshState == RELEASE_TO_REFRESH) {
//准备开始刷新
prepareForRefresh();
} else {
// Abort refresh
resetHeader();
}
}
break;
}
return super.onTouchEvent(event);
}
@Override
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
if (mCurrentScrollState == SCROLL_STATE_TOUCH_SCROLL && mRefreshState != REFRESHING) {
if (firstVisibleItem == 0) {
if ((mRefreshView.getBottom() >= mRefreshViewHeight)
&& mRefreshState != RELEASE_TO_REFRESH) {
mRefreshViewText.setText(R.string.pull_to_refresh_release_label_it);
mRefreshViewImage.clearAnimation();
mRefreshViewImage.startAnimation(mFlipAnimation);
mRefreshState = RELEASE_TO_REFRESH;
} else if (mRefreshView.getBottom() < mRefreshViewHeight
&& mRefreshState != PULL_TO_REFRESH) {
mRefreshViewText.setText(R.string.pull_to_refresh_pull_label_it);
mRefreshViewImage.clearAnimation();
mRefreshViewImage.startAnimation(mReverseFlipAnimation);
mRefreshState = PULL_TO_REFRESH;
}
}
}
if (mOnScrollListener != null) {
mOnScrollListener.onScroll(view, firstVisibleItem, visibleItemCount, totalItemCount);
}
}
@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
mCurrentScrollState = scrollState;
if (mOnScrollListener != null) {
mOnScrollListener.onScrollStateChanged(view, scrollState);
}
}
/**
* Sets the header padding back to original size.
*/
private void resetHeaderPadding() {
mRefreshView.setPadding(
mRefreshView.getPaddingLeft(),
mRefreshOriginalTopPadding,
mRefreshView.getPaddingRight(),
mRefreshView.getPaddingBottom());
}
public void prepareForRefresh() {
if (mRefreshState != REFRESHING) {
mRefreshState = REFRESHING;
mRefreshOriginalTopPadding = 0;
resetHeaderPadding();
mRefreshViewImage.clearAnimation();
mRefreshViewImage.setVisibility(View.GONE);
mRefreshViewProgress.setVisibility(View.VISIBLE);
mRefreshViewText.setText(R.string.pull_to_refresh_refreshing_label_it);
onRefresh();
}
}
private void resetHeader() {
mRefreshState = PULL_TO_REFRESH;
mRefreshOriginalTopPadding = -mRefreshViewHeight;
resetHeaderPadding();
mRefreshViewImage.clearAnimation();
mRefreshViewImage.setVisibility(View.VISIBLE);
mRefreshViewProgress.setVisibility(View.GONE);
mRefreshViewText.setText(R.string.pull_to_refresh_pull_label_it);
}
/**
* 开始回调刷新
*/
public void onRefresh() {
Log.d(TAG, "onRefresh");
if (mOnRefreshListener != null) {
mOnRefreshListener.onRefresh();
}
}
/**
* Resets the list to a normal state after a refresh.
*/
public void onRefreshComplete() {
Log.d(TAG, "onRefreshComplete");
resetHeader();
}
@Override
public void onClick(View v) {
Log.d(TAG, "onClick");
}
/**
* Interface definition for a callback to be invoked when list should be
* refreshed.
*/
public interface OnRefreshListener {
/**
* Called when the list should be refreshed.
* <p>
* A call to {@link PullToRefreshListView #onRefreshComplete()} is
* expected to indicate that the refresh has completed.
*/
public void onRefresh();
}
}上面代码就完成了,上下拉刷新工作, 直接拷贝到工程无需任何修改就可使用
当然它还需一个"头布局"
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/pull_to_refresh_header"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#F3F3F3"
android:orientation="vertical" >
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingTop="23dip" >
<LinearLayout
android:id="@+id/pull_to_refresh_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:orientation="vertical" >
<TextView
android:id="@+id/pull_to_refresh_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:gravity="center"
android:text="@string/pull_to_refresh_pull_label"
android:textColor="#777777"
android:textSize="16sp" />
<TextView
android:id="@+id/pull_to_refresh_updated_at"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:gravity="center"
android:text="@string/pull_to_refresh_updated_at"
android:textColor="#999999"
android:textSize="14sp" />
</LinearLayout>
<ProgressBar
android:id="@+id/pull_to_refresh_progress"
android:layout_width="30dip"
android:layout_height="30dip"
android:layout_marginRight="22dip"
android:layout_marginTop="5dip"
android:layout_toLeftOf="@+id/pull_to_refresh_view"
android:indeterminate="true"
android:indeterminateDrawable="@anim/ic_loading_refresh"
android:visibility="gone" />
<ImageView
android:id="@+id/pull_to_refresh_image"
android:layout_width="32dip"
android:layout_height="32dip"
android:layout_marginRight="20dip"
android:layout_marginTop="5dip"
android:layout_toLeftOf="@+id/pull_to_refresh_view"
android:contentDescription="@string/app_name"
android:gravity="center"
android:src="@drawable/ic_refresh_down" />
</RelativeLayout>
<View
android:layout_width="fill_parent"
android:layout_height="15dip" />
</LinearLayout>
此外代码中还用到了 时间的工具类: 如下
public class SharedPreferencesHelper {
private static final String SHARED_PATH = "fda_shared";
private static SharedPreferencesHelper instance;
private SharedPreferences sp;
private SharedPreferences.Editor editor;
public static SharedPreferencesHelper getInstance(Context context) {
if (instance == null && context != null) {
instance = new SharedPreferencesHelper(context);
}
return instance;
}
private SharedPreferencesHelper(Context context) {
sp = context.getSharedPreferences(SHARED_PATH, Context.MODE_PRIVATE);
editor = sp.edit();
}
public long getLongValue(String key) {
if (key != null && !key.equals("")) {
return sp.getLong(key, 0);
}
return 0;
}
public String getStringValue(String key) {
if (key != null && !key.equals("")) {
return sp.getString(key, null);
}
return null;
}
public int getIntValue(String key) {
if (key != null && !key.equals("")) {
return sp.getInt(key, 0);
}
return 0;
}
public int getIntValueByDefault(String key)
{
if (key != null && !key.equals("")) {
return sp.getInt(key, 0);
}
return 0;
}
public boolean getBooleanValue(String key) {
if (key != null && !key.equals("")) {
return sp.getBoolean(key, false);
}
return true;
}
public float getFloatValue(String key) {
if (key != null && !key.equals("")) {
return sp.getFloat(key, 0);
}
return 0;
}
public void putStringValue(String key, String value) {
if (key != null && !key.equals("")) {
editor = sp.edit();
editor.putString(key, value);
editor.commit();
}
}
public void putIntValue(String key, int value) {
if (key != null && !key.equals("")) {
editor = sp.edit();
editor.putInt(key, value);
editor.commit();
}
}
public void putBooleanValue(String key, boolean value) {
if (key != null && !key.equals("")) {
editor = sp.edit();
editor.putBoolean(key, value);
editor.commit();
}
}
public void putLongValue(String key, long value) {
if (key != null && !key.equals("")) {
editor = sp.edit();
editor.putLong(key, value);
editor.commit();
}
}
public void putFloatValue(String key, Float value) {
if (key != null && !key.equals("")) {
editor = sp.edit();
editor.putFloat(key, value);
editor.commit();
}
}
}public class SharedPreferencesTag {
public static final String DEMO_KEY="demo_key";
}public class UIUtils {
/**
* 设置上次更新数据时间
* @param listView
* @param key key表示具体某个列表
*/
public static void setPullToRefreshLastUpdated(PullToRefreshListView listView, String key,Context pContext) {
SharedPreferencesHelper spHelper = SharedPreferencesHelper.getInstance(pContext);
long lastUpdateTimeStamp = spHelper.getLongValue(key);
listView.setLastUpdated(getUpdateTimeString(lastUpdateTimeStamp));
}
/**
* 保存更新数据时间
* @param listView
* @param key key表示具体某个列表
*/
public static void savePullToRefreshLastUpdateAt(PullToRefreshListView listView, String key,Context pContext) {
listView.onRefreshComplete();
SharedPreferencesHelper spHelper = SharedPreferencesHelper.getInstance(pContext);
long lastUpdateTimeStamp=System.currentTimeMillis();
spHelper.putLongValue(key, lastUpdateTimeStamp);
listView.setLastUpdated(getUpdateTimeString(lastUpdateTimeStamp));
}
/**
* 更新时间字符串
* @param timestamp
* @return
*/
@SuppressLint("SimpleDateFormat")
public static String getUpdateTimeString(long timestamp) {
if (timestamp <= 0) {
return "上次更新时间:";
} else {
String textDate = "上次更新时间:";
Calendar now = Calendar.getInstance();
Calendar c = Calendar.getInstance();
c.setTimeInMillis(timestamp);
if (c.get(Calendar.YEAR) == now.get(Calendar.YEAR)
&& c.get(Calendar.MONTH) == now.get(Calendar.MONTH)
&& c.get(Calendar.DATE) == now.get(Calendar.DATE)) {
SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");
return textDate += sdf.format(c.getTime());
} else if (c.get(Calendar.YEAR) == now.get(Calendar.YEAR)) {
SimpleDateFormat sdf = new SimpleDateFormat("MM/dd HH:mm");
return textDate += sdf.format(c.getTime());
} else {
SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd HH:mm");
return textDate += sdf.format(c.getTime());
}
}
}
}这样就完成了, 测试效果图
源码地址:https://yunpan.cn/cryrD4r7PIgWb （提取码：fcb1）
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如果觉得上面的写法太麻烦,或者根本就不想自己写代码,那就用第三方库吧,PullToRefresh
使用步骤:
1. https://github.com/cardview/Android-PullToRefresh 下载源码
2. 解压下载文件, 把library 作为Module导入 Android studio
3. 把该library 最为库,引入 自己工程中
引用文章:http://blog.csdn.net/hantangsongming/article/details/42490277
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谷歌也推出了一种下拉刷新方式:
SwipeRefreshLayout ,但是它只支持下拉刷新,并不支持 上拉加载更多
public class MainActivity extends AppCompatActivity {
private RecyclerView demo_recycler;
private LinearLayoutManager linearLayoutManager;
private RefreshRecyclerAdpater adapter;
private SwipeRefreshLayout demo_swiperefreshlayout;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
demo_recycler=(RecyclerView)this.findViewById(R.id.demo_recycler);
linearLayoutManager=new LinearLayoutManager(this);
linearLayoutManager.setOrientation(OrientationHelper.VERTICAL);
demo_recycler.setLayoutManager(linearLayoutManager);
demo_recycler.setAdapter(adapter = new RefreshRecyclerAdpater(this));
demo_swiperefreshlayout=(SwipeRefreshLayout)this.findViewById(R.id.demo_swiperefreshlayout);
//这是设置圆圈背景色---白色
demo_swiperefreshlayout.setProgressBackgroundColorSchemeColor(getResources().getColor(android.R.color.white));
//设置进度条颜色,最多可以设置4种,每转一圈变换一种颜色
demo_swiperefreshlayout.setColorSchemeResources(android.R.color.holo_blue_light, android.R.color.holo_green_light, android.R.color.holo_red_light, android.R.color.holo_orange_light);
//设置圆圈距离顶部距离
demo_swiperefreshlayout.setProgressViewOffset(false, 0, 50);
//模拟联网获取数据
demo_swiperefreshlayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
List<String> temp=new ArrayList<String>();
for(int i=0;i<5;i++){
temp.add("refresh item "+i);
}
adapter.addItem(temp);
if(demo_swiperefreshlayout.isRefreshing()) {
demo_swiperefreshlayout.setRefreshing(false);
}
}
},5000);
Toast.makeText(MainActivity.this,"下拉刷新",Toast.LENGTH_SHORT).show();
}
});
}
}对应的RecyclerView 的adapter
public class RefreshRecyclerAdpater extends RecyclerView.Adapter<RefreshRecyclerAdpater.ViewHolder>{
private LayoutInflater mInflater;
private List<String> mTitles=null;
public RefreshRecyclerAdpater(Context context){
this.mInflater=LayoutInflater.from(context);
this.mTitles=new ArrayList<String>();
for (int i=0;i<20;i++){
int index=i+1;
mTitles.add("item"+index);
}
}
/**
* item显示类型
* @param parent
* @param viewType
* @return
*/
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
final View view=mInflater.inflate(R.layout.item_recycler_layout,parent,false);
//这边可以做一些属性设置，甚至事件监听绑定
//view.setBackgroundColor(Color.RED);
ViewHolder viewHolder=new ViewHolder(view);
return viewHolder;
}
/**
* 数据的绑定显示
* @param holder
* @param position
*/
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
holder.item_tv.setText(mTitles.get(position));
holder.itemView.setTag(position);
}
@Override
public int getItemCount() {
return mTitles.size();
}
//自定义的ViewHolder，持有每个Item的的所有界面元素
public static class ViewHolder extends RecyclerView.ViewHolder {
public TextView item_tv;
public ViewHolder(View view){
super(view);
item_tv = (TextView)view.findViewById(R.id.item_tv);
}
}
//添加数据
/**
* 添加最新数据
* @param newDatas
*/
public void addItem(List<String> newDatas) {
newDatas.addAll(mTitles);
mTitles.removeAll(mTitles);
mTitles.addAll(newDatas);
notifyDataSetChanged();
}
}布局文件:
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.SwipeRefreshLayout
android:id="@+id/demo_swiperefreshlayout"
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scrollbars="vertical">
<android.support.v7.widget.RecyclerView
android:id="@+id/demo_recycler"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
</android.support.v7.widget.RecyclerView> </android.support.v4.widget.SwipeRefreshLayout>