Android常用控件之下拉刷新Wifi列表

 

界面

关键代码

下拉列表类

package com.example.dropdownrefresh.ui;

import java.text.SimpleDateFormat;

import java.util.Date;

import com.example.dropdownrefresh.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;

/**

* 下拉列表类

* @author Administrator

*

*/

public class DropdownListView extends ListView implements OnScrollListener {

private static final String TAG = listview;

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 boolean isRefreshable;

public DropdownListView(Context context) {

super(context);

// TODO Auto-generated constructor stub

init(context);

}

public DropdownListView(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;[!--empirenews.page--]

isRefreshable = false;

}

@Override

public void onScroll(AbsListView arg0, int firstVisiableItem, int arg2,

int arg3) {

// TODO Auto-generated method stub

firstItemIndex = firstVisiableItem;

}

@Override

public void onScrollStateChanged(AbsListView view, int scrollState) {

// TODO Auto-generated method stub

}

public boolean onTouchEvent(MotionEvent event) {

if (isRefreshable) {

switch (event.getAction()) {

case MotionEvent.ACTION_DOWN:

if (firstItemIndex == 0 && !isRecored) {

isRecored = true;

startY = (int) event.getY();

Log.v(TAG, 在down时候记录当前位置‘);

}

break;

case MotionEvent.ACTION_UP:

if (state != REFRESHING && state != LOADING) {

if (state == DONE) {

// 什么都不做

}

if (state == PULL_To_REFRESH) {

state = DONE;

changeHeaderViewByState();

Log.v(TAG, 由下拉刷新状态，到done状态);

}

if (state == RELEASE_To_REFRESH) {

state = REFRESHING;

changeHeaderViewByState();

onRefresh();

Log.v(TAG, 由松开刷新状态，到done状态);

}

}

isRecored = false;

isBack = false;

break;

case MotionEvent.ACTION_MOVE:

int tempY = (int) event.getY();

if (!isRecored && firstItemIndex == 0) {

Log.v(TAG, 在move时候记录下位置);

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();

Log.v(TAG, 由松开刷新状态转变到下拉刷新状态);

}

// 一下子推到顶了

else if (tempY - startY <= 0) {

state = DONE;

changeHeaderViewByState();

Log.v(TAG, 由松开刷新状态转变到done状态);

}

// 往下拉了，或者还没有上推到屏幕顶部掩盖head的地步

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) {

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();

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) / RATIO, 0, 0);

}

// 更新headView的paddingTop

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);

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);

// 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);

}

Log.v(TAG, 当前状态，下拉刷新);

break;

case REFRESHING:[!--empirenews.page--]

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);

Log.v(TAG, 当前状态,正在刷新...);

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);

Log.v(TAG, 当前状态，done);

break;

}

}

public void setonRefreshListener(OnRefreshListener refreshListener) {

this.refreshListener = refreshListener;

isRefreshable = true;

}

public interface OnRefreshListener {

public void onRefresh();

}

public void onRefreshComplete() {

state = DONE;

SimpleDateFormat sdf = new SimpleDateFormat(yyyy-MM-dd HH:mm:ss);

lastUpdatedTextView.setText(最近更新: + sdf.format(new Date()));

changeHeaderViewByState();

}

private void onRefresh() {

if (refreshListener != null) {

refreshListener.onRefresh();

}

}

/**

* 此方法直接照搬自网络上的一个下拉刷新的demo，此处是“估计”headView的width以及height

* @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);

}

public void setAdapter(BaseAdapter adapter) {

SimpleDateFormat sdf = new SimpleDateFormat(yyyy-MM-dd HH:mm:ss);

lastUpdatedTextView.setText(最近更新: + sdf.format(new Date()));

super.setAdapter(adapter);

}

}

main.xml

 

 

 

 

 

下拉列表松开后需要扫描Wifi，再刷新列表

 

106package com.example.dropdownrefresh;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import android.app.Activity;

import android.net.wifi.ScanResult;

import android.os.AsyncTask;

import android.os.Bundle;

import android.view.View;

import android.view.ViewGroup;[!--empirenews.page--]

import android.widget.BaseAdapter;

import android.widget.LinearLayout;

import android.widget.TextView;

import com.example.dropdownrefresh.ui.DropdownListView;

import com.example.dropdownrefresh.ui.DropdownListView.OnRefreshListener;

import com.example.dropdownrefresh.utils.WifiAdmin;

/**

* 使用下拉刷新搜索wifi

* @author Administrator

*

*/

public class MainActivity extends Activity {

WifiAdmin wifiAdmin = null;

private ArrayList

private BaseAdapter adapter;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

wifiAdmin = new WifiAdmin(this);

list = new ArrayList

RefreshList();

final DropdownListView listView = (DropdownListView) findViewById(R.id.listView);

adapter = new BaseAdapter() {

public View getView(int position, View convertView, ViewGroup parent) {

LinearLayout layout = new LinearLayout(getApplicationContext());

layout.setOrientation(LinearLayout.VERTICAL); //垂直布局

HashMap

TextView txtName = new TextView(getApplicationContext());

TextView txtSignal = new TextView(getApplicationContext());

txtName.setText(map.get(wifi_name));

txtSignal.setText(map.get(wifi_signal));

layout.addView(txtName);

layout.addView(txtSignal);

return layout;

}

public long getItemId(int position) {

return 0;

}

public Object getItem(int position) {

return null;

}

public int getCount() {

return list.size();

}

};

listView.setAdapter(adapter);

listView.setonRefreshListener(new OnRefreshListener() {

public void onRefresh() {

new AsyncTask

protected Void doInBackground(Void... params) {

try {

Thread.sleep(1000);

} catch (Exception e) {

e.printStackTrace();

}

list.clear();

RefreshList();

return null;

}

@Override

protected void onPostExecute(Void result) {

adapter.notifyDataSetChanged();

listView.onRefreshComplete();

}

}.execute(null, null, null);

}

});

}

private void RefreshList(){

wifiAdmin.startScan(); // 扫描wifi热点，前提是wifi已经打开

List wifiList = wifiAdmin.getWifiList();

for (int index = 0; index < wifiList.size(); index++) {

HashMap

map.put(wifi_name, (wifiList.get(index)).SSID);

map.put(wifi_signal, signal:

+ (-(wifiList.get(index)).level) + %);

list.add(map);

}

}

}

 

[!--empirenews.page--]