ListView下拉刷新

本内容为复制代码：

一、自定义ListView控件：

package com.xczl.smart.view;

import java.util.Date;

import com.suliang.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.View.MeasureSpec;
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;

/**
 * 自定义ListView，继承ListView实现OnScrollListener接口
 * 
 * @author Administrator
 * 
 */
public class MyListView 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 MyListView(Context context) {
		super(context);
		init(context);
	}

	public MyListView(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(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_lastUpdateTextView);

		measureView(headView);
		
		headContentHeight = headView.getMeasuredHeight();
		headContentWidth = headView.getMeasuredWidth();

		headView.setPadding(0, -1 * headContentHeight, 0, 0);
		headView.invalidate();

		Log.v("size", "" + 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;
	}

	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) {

		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:

			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;
		lastUpdatedTextView.setText("最近更新:" + new Date().toLocaleString());
		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
	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);
	}

	public void setAdapter(BaseAdapter adapter) {
		lastUpdatedTextView.setText("最近更新:" + new Date().toLocaleString());
		super.setAdapter(adapter);
	}

}

　　二、下拉布局：

<?xml version="1.0" encoding="utf-8"?>
<!-- ListView的头部 -->
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:background="@color/title_green" >

    <!-- 内容 -->

    <RelativeLayout
        android:id="@+id/head_contentlayout"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:paddingLeft="30dp" >

        <!-- 箭头图像     进度条 -->

        <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/arrow" />

            <ProgressBar
                android:id="@+id/head_progressBar"
                style="@android:style/Widget.ProgressBar.Inverse"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="center"
                android:visibility="gone" />
        </FrameLayout>

        <!-- 提示（下拉刷新）   最近更新 -->

        <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:layout_marginTop="3dp"
                android:text="下拉刷新"
                android:textSize="20sp" />
            <TextView
                android:id="@+id/head_lastUpdateTextView"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginTop="3dp"
                android:text="最后更新"
                android:textColor="#FF0000"
                android:textSize="10sp" />
        </LinearLayout>
    </RelativeLayout>

</LinearLayout>

　　三、代码中使用：

 MyListView mListView = (MyListView)view.findViewById(R.id.mlist);
/** 下拉刷新 */
		mListView.setonRefreshListener(new com.xczl.smart.view.MyListView.OnRefreshListener() {
			public void onRefresh() {
				new AsyncTask<Void, Void, Void>() {
					protected Void doInBackground(Void... params) {
						try {
							Thread.sleep(1000);
						} catch (Exception e) {
							e.printStackTrace();
						}
						return null;
					}
					@Override
					protected void onPostExecute(Void result) {
						
						
						mListView.onRefreshComplete();
					}

				}.execute();
			}
		});