Android UI--自定义ListView(实现下拉刷新+加载更多）

@Override

public boolean onTouchEvent(MotionEvent event) {

final int y = (int) event.getY(); // 获取点击位置的Y坐标

switch (event.getAction()) {

case MotionEvent.ACTION_UP: // 手指抬起

if (!isVerticalScrollBarEnabled()) {

setVerticalScrollBarEnabled(true);

}

if (getFirstVisiblePosition() == 0 && mRefreshState != REFRESHING) {

if ((mRefreshHeaderView.getBottom() > mRefreshViewHeight

|| mRefreshHeaderView.getTop() >= 0)

&& mRefreshState == RELEASE_TO_REFRESH) {

// Initiate the refresh

mRefreshState = REFRESHING; // 刷新状态

prepareForRefresh();

onRefresh();

} else if (mRefreshHeaderView.getBottom() < mRefreshViewHeight

|| mRefreshHeaderView.getTop() < 0) {

// Abort refresh and scroll down below the refresh view

resetHeader();

setSelection(1);

}

}

break;

case MotionEvent.ACTION_DOWN:

mLastMotionY = y;

break;

case MotionEvent.ACTION_MOVE:

applyHeaderPadding(event);

break;

}

return super.onTouchEvent(event);

}

private void applyHeaderPadding(MotionEvent ev) {

final int historySize = ev.getHistorySize();

// Workaround for getPointerCount() which is unavailable in 1.5

// (it’s always 1 in 1.5)

int pointerCount = 1;

try {

Method method = MotionEvent.class.getMethod(“getPointerCount”);

pointerCount = (Integer)method.invoke(ev);

} catch (NoSuchMethodException e) {

pointerCount = 1;

} catch (IllegalArgumentException e) {

throw e;

} catch (IllegalAccessException e) {

System.err.println("unexpected " + e);

} catch (InvocationTargetException e) {

System.err.println("unexpected " + e);

}

for (int h = 0; h < historySize; h++) {

for (int p = 0; p < pointerCount; p++) {

if (mRefreshState == RELEASE_TO_REFRESH) {

if (isVerticalFadingEdgeEnabled()) {

setVerticalScrollBarEnabled(false);

}

int historicalY = 0;

try {

// For Android > 2.0

Method method = MotionEvent.class.getMethod(

“getHistoricalY”, Integer.TYPE, Integer.TYPE);

historicalY = ((Float) method.invoke(ev, p, h)).intValue();

} catch (NoSuchMethodException e) {

// For Android < 2.0

historicalY = (int) (ev.getHistoricalY(h));

} catch (IllegalArgumentException e) {

throw e;

} catch (IllegalAccessException e) {

System.err.println("unexpected " + e);

} catch (InvocationTargetException e) {

System.err.println("unexpected " + e);

}

// Calculate the padding to apply, we divide by 1.7 to

// simulate a more resistant effect during pull.

int topPadding = (int) (((historicalY - mLastMotionY)

• mRefreshViewHeight) / 1.7);

// 设置上、下、左、右四个位置的间隙间隙

mRefreshHeaderView.setPadding(

mRefreshHeaderView.getPaddingLeft(),

topPadding,

mRefreshHeaderView.getPaddingRight(),

mRefreshHeaderView.getPaddingBottom());

}

}

}

}

/**

• Sets the header padding back to original size.
• 设置头部填充会原始大小

*/

private void resetHeaderPadding() {

mRefreshHeaderView.setPadding(

mRefreshHeaderView.getPaddingLeft(),

mRefreshOriginalTopPadding,

mRefreshHeaderView.getPaddingRight(),

mRefreshHeaderView.getPaddingBottom());

}

/**

• Resets the header to the original state.
• 重新设置头部为原始状态

*/

private void resetHeader() {

if (mRefreshState != TAP_TO_REFRESH) {

mRefreshState = TAP_TO_REFRESH;

resetHeaderPadding();

// Set refresh view text to the pull label

mRefreshViewText.setText(R.string.pull_to_refresh_tap_label);

// Replace refresh drawable with arrow drawable

mRefreshViewImage.setImageResource(R.drawable.ic_pulltorefresh_arrow);

// Clear the full rotation animation

mRefreshViewImage.clearAnimation();

// Hide progress bar and arrow.

mRefreshViewImage.setVisibility(View.GONE);

mRefreshViewProgress.setVisibility(View.GONE);

}

}

/**

• 重设ListView尾部视图为初始状态

*/

private void resetFooter() {

if(mLoadState != TAP_TO_LOADMORE) {

mLoadState = TAP_TO_LOADMORE;

// 进度条设置为不可见

mLoadMoreProgress.setVisibility(View.GONE);

// 按钮的文本替换为“加载更多”

mLoadMoreText.setText(R.string.loadmore_label);

}

}

/**

• 测量视图的大小
• @param child

*/

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);

}

@Override

public void onScroll(AbsListView view, int firstVisibleItem,

int visibleItemCount, int totalItemCount) {

// When the refresh view is completely visible, change the text to say

// “Release to refresh…” and flip the arrow drawable.

if (mCurrentScrollState == SCROLL_STATE_TOUCH_SCROLL

&& mRefreshState != REFRESHING) {

if (firstVisibleItem == 0) { // 如果第一个可见条目为0

mRefreshViewImage.setVisibility(View.VISIBLE); // 让指示箭头变得可见

/如果头部视图相对与父容器的位置大于其自身高度+20或者头部视图的顶部位置>0,并且要在刷新状态不等于"释放以刷新"/

if ((mRefreshHeaderView.getBottom() > mRefreshViewHeight + 20

|| mRefreshHeaderView.getTop() >= 0)

&& mRefreshState != RELEASE_TO_REFRESH) {

mRefreshViewText.setText(R.string.pull_to_refresh_release_label);// 设置刷新文本为"Release to refresh…"

mRefreshViewImage.clearAnimation(); // 清除动画

mRefreshViewImage.startAnimation(mFlipAnimation); // 启动动画

mRefreshState = RELEASE_TO_REFRESH; // 更改刷新状态为“释放以刷新"

} else if (mRefreshHeaderView.getBottom() < mRefreshViewHeight + 20

&& mRefreshState != PULL_TO_REFRESH) {

mRefreshViewText.setText(R.string.pull_to_refresh_pull_label);// 设置刷新文本为"Pull to refresh…"

if (mRefreshState != TAP_TO_REFRESH) {

mRefreshViewImage.clearAnimation();

mRefreshViewImage.startAnimation(mReverseFlipAnimation);

}

mRefreshState = PULL_TO_REFRESH;

}

} else {

mRefreshViewImage.setVisibility(View.GONE); // 让刷新箭头不可见

resetHeader(); // 重新设置头部为原始状态

}

} else if (mCurrentScrollState == SCROLL_STATE_FLING

&& firstVisibleItem == 0

&& mRefreshState != REFRESHING) {

setSelection(1);

}

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);

}

}

/为刷新做准备/

public void prepareForRefresh() {

resetHeaderPadding();

mRefreshViewImage.setVisibility(View.GONE); // 去掉刷新的箭头

// We need this hack, otherwise it will keep the previous drawable.

mRefreshViewImage.setImageDrawable(null);

mRefreshViewProgress.setVisibility(View.VISIBLE); // 圆形进度条变为可见

// Set refresh view text to the refreshing label

mRefreshViewText.setText(R.string.pull_to_refresh_refreshing_label);

mRefreshState = REFRESHING;

}

/为加载更多做准备/

public void prepareForLoadMore() {

mLoadMoreProgress.setVisibility(View.VISIBLE);

mLoadMoreText.setText(R.string.loading_label);

mLoadState = LOADING;

}

public void onRefresh() {

Log.d(TAG, “onRefresh”);

if (mOnRefreshListener != null) {

mOnRefreshListener.onRefresh();

}

}

public void OnLoadMore() {

Log.d(TAG, “onLoadMore”);

if(mOnRefreshListener != null) {

mOnRefreshListener.onLoadMore();

}

}

/**

• Resets the list to a normal state after a refresh.
• @param lastUpdated Last updated at.

*/

public void onRefreshComplete(CharSequence lastUpdated) {

setLastUpdated(lastUpdated); // 显示更新时间

onRefreshComplete();

}

/**

• Resets the list to a normal state after a refresh.

*/

public void onRefreshComplete() {

Log.d(TAG, “onRefreshComplete”);

resetHeader();

// If refresh view is visible when loading completes, scroll down to

// the next item.

if (mRefreshHeaderView.getBottom() > 0) {

invalidateViews();

setSelection(1);

}

}

public void onLoadMoreComplete() {

Log.d(TAG, “onLoadMoreComplete”);

resetFooter();

}

/**

• Invoked when the refresh view is clicked on. This is mainly used when
• there’s only a few items in the list and it’s not possible to drag the
• list.
• 点击刷新

*/

private class OnClickRefreshListener implements OnClickListener {

@Override

public void onClick(View v) {

if (mRefreshState != REFRESHING) {

prepareForRefresh();

onRefresh();

}

}

}

/**

• @author wwj
• 加载更多

*/

private class OnClickLoadMoreListener implements OnClickListener {

@Override

public void onClick(View v) {

if(mLoadState != LOADING) {

prepareForLoadMore();

OnLoadMore();

}

}

}

/**

• Interface definition for a callback to be invoked when list should be
• refreshed.
• 接口定义一个回调方法当列表应当被刷新

*/

public interface OnRefreshListener {

/**

• Called when the list should be refreshed.
• 当列表应当被刷新是调用这个方法
• A call to {@link PullToRefreshListView #onRefreshComplete()} is
• expected to indicate that the refresh has completed.

*/

public void onRefresh();

public void onLoadMore();

}

}

使用方法：

package com.markupartist.android.example.pulltorefresh;

import java.text.SimpleDateFormat;

import java.util.Arrays;

import java.util.Date;

import java.util.LinkedList;

import android.app.Activity;

import android.content.Context;

import android.os.AsyncTask;

import android.os.Bundle;

import android.widget.ArrayAdapter;

import com.markupartist.android.widget.PullToRefreshListView;

import com.markupartist.android.widget.PullToRefreshListView.OnRefreshListener;

public class PullToRefreshActivity extends Activity {

private LinkedList mListItems;

public static PullToRefreshListView weiboListView;

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.pull_to_refresh);

weiboListView = (PullToRefreshListView) findViewById(R.id.weibolist);

// Set a listener to be invoked when the list should be refreshed.

weiboListView.setOnRefreshListener(new OnRefreshListener() {

@Override

public void onRefresh() {

// Do work to refresh the list here.

new GetDataTask(PullToRefreshActivity.this, 0).execute();

}

@Override

public void onLoadMore() {

new GetDataTask(PullToRefreshActivity.this, 1).execute();

}

});

mListItems = new LinkedList();

mListItems.addAll(Arrays.asList(mStrings));

ArrayAdapter adapter = new ArrayAdapter(this,

android.R.layout.simple_list_item_1, mListItems);

weiboListView.setAdapter(adapter);

}

private class GetDataTask extends AsyncTask<Void, Void, String[]> {

private Context context;

private int index;

public GetDataTask(Context context, int index) {

this.context = context;

this.index = index;

}

@Override

protected String[] doInBackground(Void… params) {

// Simulates a background job.

try {

Thread.sleep(2000);

} catch (InterruptedException e) {

;

}

return mStrings;

}

@Override

protected void onPostExecute(String[] result) {

if (index == 0) {

// 将字符串“Added after refresh”添加到顶部

mListItems.addFirst(“Added after refresh…”);

SimpleDateFormat format = new SimpleDateFormat(

“yyyy年MM月dd日 HH:mm”);

String date = format.format(new Date());

// Call onRefreshComplete when the list has been refreshed.

weiboListView.onRefreshComplete(date);

} else if (index == 1) {

mListItems.addLast(“Added after loadmore…”);

weiboListView.onLoadMoreComplete();

}

super.onPostExecute(result);

}

}

public static String[] mStrings = { “一条微博”, “两条微博”, “三条微博”, “四条微博”, “五条微博”,

“六条微博”, “七条微博”, “八条微博”, “九条微博”, “十条微博”, “十一条微博”, “十二条微博” };

}

下拉刷新的那个头部布局

/2013.08.22_PullToRefresh_ListView_Demo/res/layout/pull_to_refresh_header.xml
<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android=“http://schemas.android.com/apk/res/android”

android:layout_width=“fill_parent”

android:layout_height=“fill_parent”

android:gravity=“center”

android:paddingBottom=“15dip”

android:paddingTop=“10dip” >

<ProgressBar

android:id=“@+id/pull_to_refresh_progress”

style=“?android:attr/progressBarStyleSmall”

android:layout_width=“wrap_content”

android:layout_height=“wrap_content”

android:layout_centerVertical=“true”

android:layout_marginLeft=“30dip”

android:layout_marginRight=“20dip”

android:layout_marginTop=“10dip”

android:indeterminate=“true”

android:visibility=“gone” />

<ImageView

android:id=“@+id/pull_to_refresh_image”

android:layout_width=“wrap_content”

android:layout_height=“wrap_content”

android:layout_gravity=“center”

android:layout_marginLeft=“30dip”

android:layout_marginRight=“20dip”

android:gravity=“center”

android:src=“@drawable/ic_pulltorefresh_arrow”

android:visibility=“gone” />

<TextView

android:id=“@+id/pull_to_refresh_text”

android:layout_width=“fill_parent”

android:layout_height=“wrap_content”

android:layout_gravity=“center”

android:gravity=“center”

android:paddingTop=“5dip”

android:text=“@string/pull_to_refresh_tap_label”

android:textAppearance=“?android:attr/textAppearanceMedium”

android:textStyle=“bold” />

<TextView

android:id=“@+id/pull_to_refresh_updated_at”

android:layout_width=“fill_parent”

android:layout_height=“wrap_content”

android:layout_below=“@+id/pull_to_refresh_text”

android:layout_gravity=“center”

android:gravity=“center”

android:textAppearance=“?android:attr/textAppearanceSmall”

android:visibility=“gone” />

加载更多的底部布局

/2013.08.22_PullToRefresh_ListView_Demo/res/layout/loadmore_footer.xml
<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android=“http://schemas.android.com/apk/res/android”

android:id=“@+id/loadmore_layout”

android:layout_width=“match_parent”

android:layout_height=“wrap_content”

android:gravity=“center”

android:paddingBottom=“15dip”

android:paddingTop=“10dip” >

<ProgressBar

android:id=“@+id/loadmore_progress”

style=“?android:attr/progressBarStyleSmall”

android:layout_width=“wrap_content”

android:layout_height=“wrap_content”

android:layout_centerVertical=“true”

android:layout_marginLeft=“30dip”

android:layout_marginRight=“20dip”

android:layout_marginTop=“10dip”

android:indeterminate=“true”

android:visibility=“gone” />

<TextView

android:id=“@+id/loadmore_text”

android:layout_width=“fill_parent”

android:layout_height=“wrap_content”

android:layout_gravity=“center”

android:gravity=“center”

android:paddingTop=“5dip”

android:text=“@string/loadmore_label”

android:textAppearance=“?android:attr/textAppearanceMedium”

android:textStyle=“bold” />

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droid:background=“@drawable/weibo_list_item_selector”

android:text=“@string/loadmore_label”

android:textColor=“@color/loadmore_btn_selector”

android:textSize=“18.0sp” />

–>

<ProgressBar

android:id=“@+id/loadmore_progress”

style=“?android:attr/progressBarStyleSmall”

android:layout_width=“wrap_content”

android:layout_height=“wrap_content”

android:layout_centerVertical=“true”

android:layout_marginLeft=“30dip”

android:layout_marginRight=“20dip”

android:layout_marginTop=“10dip”

android:indeterminate=“true”

android:visibility=“gone” />

<TextView

android:id=“@+id/loadmore_text”

android:layout_width=“fill_parent”

android:layout_height=“wrap_content”

android:layout_gravity=“center”

android:gravity=“center”

android:paddingTop=“5dip”

android:text=“@string/loadmore_label”

android:textAppearance=“?android:attr/textAppearanceMedium”

android:textStyle=“bold” />

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