ListView下拉回弹刷新

来源：互联网发布：数据分析服务合同编辑：程序博客网时间：2024/06/11 20:25

现在QQ空间和新浪微博ListView下拉刷新做的比较炫，正好公司也有这样的需求，实现起来还是相对简单的。关键是要自定义一个ListView头部（初始化的时候里面的控件是不可见的），然后在点击、拖动、松开的时候触发事件，显示ListView头，计算出拖拽的距离，跟ListView头的高度做比较，以此来显示对应的ListView头里的控件（下拉图标、提示文字、圆形进度条等）。好了，下面贴出效果图：

好，开始上代码，先是布局文件main.xml，没什么好说的：

<?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:orientation="vertical"
android:background="@color/mainColor" >
<com.focustech.android.CustomListView
android:id="@+id/list"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
</LinearLayout>

ListView头布局head.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<RelativeLayout
android:id="@+id/head_contentLayout"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingLeft="30dp" >
<FrameLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_centerVertical="true" >
<ImageView
android:id="@+id/head_arrowImageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:src="@drawable/ic_pulltorefresh_arrow" />
<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:visibility="gone" />
</FrameLayout>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:gravity="center_horizontal"
android:orientation="vertical" >
<TextView
android:id="@+id/head_tipsTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="下拉可以刷新"
android:textColor="#ffffff"
android:textSize="20sp" />
<TextView
android:id="@+id/head_lastUpdatedTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="最近更新"
android:textColor="#cc6600"
android:textSize="10sp" />
</LinearLayout>
</RelativeLayout>
</LinearLayout>

ListView item项布局listview_item.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:Android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<ImageView
android:id="@+id/imageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/pretty_girl"
/>
<TextView
android:id="@+id/textview"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
</LinearLayout>

清单文件也贴出来吧，其实就是自动生成的，什么都不用改：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.focustech.android"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="14" />
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<activity
android:label="@string/app_name"
android:name="com.focustech.android.MainActivity" >
<intent-filter >
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>

此Demo的Activity：

package com.focustech.android;
import android.app.Activity;
import android.database.DataSetObserver;
import android.graphics.Color;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ListAdapter;
import android.widget.TextView;
import com.focustech.android.CustomListView.OnRefreshListener;
import com.focustech.android.R;
public class MainActivity extends Activity {
private ListAdapter adapter;
int size = 10;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
final CustomListView list = (CustomListView) findViewById(R.id.list);
adapter = new ListAdapter() {
public void unregisterDataSetObserver(DataSetObserver arg0) {
}
public void registerDataSetObserver(DataSetObserver arg0) {
}
public boolean isEmpty() {
return false;
}
public boolean hasStableIds() {
return false;
}
public int getViewTypeCount() {
return 1;
}
public View getView(int position, View convertView, ViewGroup parent) {
convertView = LayoutInflater.from(getApplicationContext())
.inflate(R.layout.listview_item, null);
TextView mTextView = (TextView) convertView
.findViewById(R.id.textview);
mTextView.setText("pretty girl" + position);
mTextView.setTextColor(Color.RED);
return convertView;
}
public int getItemViewType(int arg0) {
return arg0;
}
public long getItemId(int arg0) {
return arg0;
}
public Object getItem(int arg0) {
return null;
}
public int getCount() {
return size;
}
@Override
public boolean isEnabled(int position) {
return false;
}
@Override
public boolean areAllItemsEnabled() {
return false;
}
};
list.setAdapter(adapter);
// 在list上注册自定义的监听器
list.setonRefreshListener(new OnRefreshListener() {
public void onRefresh() {
new Thread(new Runnable() {
public void run() {
try {
Thread.sleep(1000);
} catch (Exception e) {
}
runOnUiThread(new Runnable() {
public void run() {
list.onRefreshComplete();
}
});
size++;
}
}).start();
}
});
}
}

实现了OnScrollListener的自定义ListView：

package com.focustech.Android;
import java.util.Date;
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.ImageView;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.TextView;
import com.focustech.android.R;
public class CustomListView extends ListView implements OnScrollListener {
// 松开刷新标志
private final static int RELEASE_To_REFRESH = 0;
// 下拉刷新标志
private final static int PULL_To_REFRESH = 1;
// 正在刷新标志
private final static int REFRESHING = 2;
// 刷新完成标志
private final static int DONE = 3;
private LayoutInflater inflater;
private LinearLayout headView;
private TextView tipsTextview;
private TextView lastUpdatedTextView;
private ImageView arrowImageView;
private ProgressBar progressBar;
// 用来设置箭头图标动画效果
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;
public OnRefreshListener refreshListener;
private final static String TAG = "Monitor Current Infomation";
public CustomListView(Context context, AttributeSet attrs) {
super(context, attrs);
init(context);
}
private void init(Context context) {
inflater = LayoutInflater.from(context);
headView = (LinearLayout) inflater.inflate(R.layout.head, null);
arrowImageView = (ImageView) headView
.findViewById(R.id.head_arrowImageView);
arrowImageView.setMinimumWidth(50);
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);
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(500);
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(500);
reverseAnimation.setFillAfter(true);
}
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) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
if (firstItemIndex == 0 && !isRecored) {
startY = (int) event.getY();
isRecored = true;
Log.v(TAG, "记录按下时的位置");
}
break;
case MotionEvent.ACTION_UP:
if (state != REFRESHING) {
if (state == DONE) {
Log.v(TAG, "什么都不做");
}
if (state == PULL_To_REFRESH) {
state = DONE;
changeHeaderViewByState();
Log.v(TAG, "由下拉刷新状态到刷新完成状态");
}
if (state == RELEASE_To_REFRESH) {
state = REFRESHING;
changeHeaderViewByState();
onRefresh();
Log.v(TAG, "由松开刷新状态，到刷新完成状态");
}
}
isRecored = false;
isBack = false;
break;
case MotionEvent.ACTION_MOVE:
int tempY = (int) event.getY();
if (!isRecored && firstItemIndex == 0) {
Log.v(TAG, "记录拖拽时的位置");
isRecored = true;
startY = tempY;
}
if (state != REFRESHING && isRecored) {
// 可以松开刷新了
if (state == RELEASE_To_REFRESH) {
// 往上推，推到屏幕足够掩盖head的程度，但还没有全部掩盖
if ((tempY - startY < headContentHeight)
&& (tempY - startY) > 0) {
state = PULL_To_REFRESH;
changeHeaderViewByState();
Log.v(TAG, "由松开刷新状态转变到下拉刷新状态");
}
// 一下子推到顶
else if (tempY - startY <= 0) {
state = DONE;
changeHeaderViewByState();
Log.v(TAG, "由松开刷新状态转变到done状态");
}
// 往下拉，或者还没有上推到屏幕顶部掩盖head
else {
// 不用进行特别的操作，只用更新paddingTop的值就行了
}
}
// 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) {
// 下拉到可以进入RELEASE_TO_REFRESH的状态
if (tempY - startY >= headContentHeight) {
state = RELEASE_To_REFRESH;
isBack = true;
changeHeaderViewByState();
Log.v(TAG, "由done或者下拉刷新状态转变到松开刷新");
}
// 上推到顶了
else if (tempY - startY <= 0) {
state = DONE;
changeHeaderViewByState();
Log.v(TAG, "由Done或者下拉刷新状态转变到done状态");
}
}
// done状态下
if (state == DONE) {
if (tempY - startY > 0) {
state = PULL_To_REFRESH;
changeHeaderViewByState();
}
}
// 更新headView的size
if (state == PULL_To_REFRESH) {
headView.setPadding(0, -1 * headContentHeight
+ (tempY - startY), 0, 0);
headView.invalidate();
}
// 更新headView的paddingTop
if (state == RELEASE_To_REFRESH) {
headView.setPadding(0, tempY - startY - headContentHeight,
0, 0);
headView.invalidate();
}
}
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("松开可以刷新");
Log.v(TAG, "当前状态，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);
if (isBack) {
isBack = false;
arrowImageView.clearAnimation();
arrowImageView.startAnimation(reverseAnimation);
tipsTextview.setText("下拉可以刷新");
} else {
tipsTextview.setText("下拉可以刷新");
}
Log.v(TAG, "当前状态，下拉刷新");
break;
case REFRESHING:
headView.setPadding(0, 0, 0, 0);
headView.invalidate();
progressBar.setVisibility(View.VISIBLE);
arrowImageView.clearAnimation();
arrowImageView.setVisibility(View.GONE);
tipsTextview.setText("正在刷新，请稍后...");
lastUpdatedTextView.setVisibility(View.GONE);
Log.v(TAG, "当前状态,正在刷新...");
break;
case DONE:
headView.setPadding(0, -1 * headContentHeight, 0, 0);
headView.invalidate();
progressBar.setVisibility(View.GONE);
arrowImageView.clearAnimation();
// 此处更换图标
arrowImageView.setImageResource(R.drawable.ic_pulltorefresh_arrow);
tipsTextview.setText("下拉可以刷新");
lastUpdatedTextView.setVisibility(View.VISIBLE);
Log.v(TAG, "当前状态，done");
break;
}
}
public void setonRefreshListener(OnRefreshListener refreshListener) {
this.refreshListener = refreshListener;
}
public interface OnRefreshListener {
public void onRefresh();
}
public void onRefreshComplete() {
state = DONE;
lastUpdatedTextView.setText("最近更新:" + new Date().toLocaleString());
changeHeaderViewByState();
}
private void onRefresh() {
if (refreshListener != null) {
refreshListener.onRefresh();
}
}
// 此处是“估计”headView的width以及height
private void measureView(View child) {
ViewGroup.LayoutParams p = child.getLayoutParams();
if (p == null) {
p = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.FILL_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);
}
}