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 Android教程網 >> Android技術 >> 關於Android編程 >> Android常用控件之下拉刷新Wifi列表

Android常用控件之下拉刷新Wifi列表

編輯：關於Android編程

有些列表信息需要手動去更新，此時比較常用的就是下拉刷新列表，在這裡就使用下拉列表來刷新當前Wifi信息

目錄結構

\

界面

\ \

\ \

關鍵代碼

下拉列表類

 

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;

/**
 * 下拉列表類
 * @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;

	// 實際的padding的距離與界面上偏移距離的比例
	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;

	// 用於保證startY的值在一個完整的touch事件中只被記錄一次
	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;
		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時候記錄當前位置‘);
				}
				break;

			case MotionEvent.ACTION_UP:

				if (state != REFRESHING && state != LOADING) {
					if (state == DONE) {
						// 什麼都不做
					}
					if (state == PULL_To_REFRESH) {
						state = DONE;
						changeHeaderViewByState();

						Log.v(TAG, 由下拉刷新狀態，到done狀態);
					}
					if (state == RELEASE_To_REFRESH) {
						state = REFRESHING;
						changeHeaderViewByState();
						onRefresh();

						Log.v(TAG, 由松開刷新狀態，到done狀態);
					}
				}

				isRecored = false;
				isBack = false;

				break;

			case MotionEvent.ACTION_MOVE:
				int tempY = (int) event.getY();

				if (!isRecored && firstItemIndex == 0) {
					Log.v(TAG, 在move時候記錄下位置);
					isRecored = true;
					startY = tempY;
				}

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

					// 保證在設置padding的過程中，當前的位置一直是在head，否則如果當列表超出屏幕的話，當在上推的時候，列表會同時進行滾動

					// 可以松手去刷新了
					if (state == RELEASE_To_REFRESH) {

						setSelection(0);

						// 往上推了，推到了屏幕足夠掩蓋head的程度，但是還沒有推到全部掩蓋的地步
						if (((tempY - startY) / RATIO < headContentHeight)
								&& (tempY - startY) > 0) {
							state = PULL_To_REFRESH;
							changeHeaderViewByState();

							Log.v(TAG, 由松開刷新狀態轉變到下拉刷新狀態);
						}
						// 一下子推到頂了
						else if (tempY - startY <= 0) {
							state = DONE;
							changeHeaderViewByState();

							Log.v(TAG, 由松開刷新狀態轉變到done狀態);
						}
						// 往下拉了，或者還沒有上推到屏幕頂部掩蓋head的地步
						else {
							// 不用進行特別的操作，只用更新paddingTop的值就行了
						}
					}
					// 還沒有到達顯示松開刷新的時候,DONE或者是PULL_To_REFRESH狀態
					if (state == PULL_To_REFRESH) {

						setSelection(0);

						// 下拉到可以進入RELEASE_TO_REFRESH的狀態
						if ((tempY - startY) / RATIO >= headContentHeight) {
							state = RELEASE_To_REFRESH;
							isBack = true;
							changeHeaderViewByState();

							Log.v(TAG, 由done或者下拉刷新狀態轉變到松開刷新);
						}
						// 上推到頂了
						else if (tempY - startY <= 0) {
							state = DONE;
							changeHeaderViewByState();

							Log.v(TAG, 由DOne或者下拉刷新狀態轉變到done狀態);
						}
					}

					// done狀態下
					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);
	}

	/**
	 * 當狀態改變時候，調用該方法，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(松開刷新);

			Log.v(TAG, 當前狀態，松開刷新);
			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狀態轉變來的
			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, 當前狀態，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);

			Log.v(TAG, 當前狀態,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, 當前狀態，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();
		}
	}

	/**
	 * 此方法直接照搬自網絡上的一個下拉刷新的demo，此處是“估計”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

 

 

 






    

    

        

        <framelayout android:layout_alignparentleft="true" android:layout_centervertical="true" android:layout_height="wrap_content" android:layout_width="wrap_content">

            

            

            

            
        </framelayout>
下拉列表松開後需要掃描Wifi，再刷新列表

 

 

package 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;
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> list;
	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 map = list.get(position);
				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(); // 掃描wifi熱點，前提是wifi已經打開
		List wifiList = wifiAdmin.getWifiList();
		for (int index = 0; index < wifiList.size(); index++) {
			HashMap map = new HashMap();
			map.put(wifi_name, (wifiList.get(index)).SSID);
			map.put(wifi_signal, signal: 
					+ (-(wifiList.get(index)).level) + %);
			list.add(map);
		}
	}
}
 
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