android学习之ListView下拉刷新

好久没写博客了，今天做了一个关于ListView下拉刷新的功能，其实最近谷歌出了SwipeRefreshLayout + RecyclerView 实现 上拉刷新 和 下拉刷新。谷歌公司只提供了下拉刷新的功能，RecyclerView的出现基本就是为了替代ListView，GridView的。作为一个新手嘛，还是从基础的来，下次再去看看RecyclerView实现方式，小伙伴们等等咯，过段是时间SwipeRefreshLayout + RecyclerView 实现 上拉刷新 和 下拉刷新的博客，我会写一篇的。

好了言归正传，先上今天的代码（晕。。不知道是不是网的原因效果图上传不了）
布局代码：

<?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="horizontal">    <!-- 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" >            <!-- 箭头 -->            <ImageView                android:id="@+id/lvHeaderArrowIv"                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:layout_gravity="center"                android:src="@drawable/ic_launcher" />            <!-- 进度条 -->            <ProgressBar                android:id="@+id/lvHeaderProgressBar"                style="?android:attr/progressBarStyleSmall"                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:layout_gravity="center"                android:visibility="gone" />        </FrameLayout>        <!-- 提示、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" >            <!-- 提示 -->            <TextView                android:id="@+id/lvHeaderTipsTv"                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:text="下拉刷新"                android:textColor="#000000"                android:textSize="20sp" />            <!-- 最近更新 -->            <TextView                android:id="@+id/lvHeaderLastUpdatedTv"                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:text="上次更新"                android:textColor="#000000"                android:textSize="10sp" />        </LinearLayout>    </RelativeLayout></LinearLayout>

listView布局：

<?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">    <com.jp.tools.MyListView        android:id="@+id/list_thing"        android:layout_width="fill_parent"        android:layout_height="fill_parent"/></LinearLayout>

自定义listview类：

package com.jp.tools;import android.content.Context;import android.util.AttributeSet;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.ImageView;import android.widget.LinearLayout;import android.widget.ListAdapter;import android.widget.ListView;import android.widget.ProgressBar;import android.widget.TextView;import com.jp.activity.R;import java.util.Date;/** * Created by Administrator on 2015/8/20. */public class MyListView extends ListView implements AbsListView.OnScrollListener{    private final static int RELEASE_To_REFRESH = 0;// 下拉过程的状态值    private final static int PULL_To_REFRESH = 1; // 从下拉返回到不刷新的状态值    private final static int REFRESHING = 2;// 正在刷新的状态值    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;    // ListView头部下拉刷新的布局    private LinearLayout headerView;    private TextView lvHeaderTipsTv;    private TextView lvHeaderLastUpdatedTv;    private ImageView lvHeaderArrowIv;    private ProgressBar lvHeaderProgressBar;    // 定义头部下拉刷新的布局的高度    private int headerContentHeight;    private RotateAnimation animation;    private RotateAnimation reverseAnimation;    private int startY;    private int state;    private boolean isBack;    // 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 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)    {        setCacheColorHint(context.getResources().getColor(R.color.write));        inflater = LayoutInflater.from(context);        headerView = (LinearLayout) inflater.inflate(R.layout.lv_header, null);        lvHeaderTipsTv = (TextView) headerView.findViewById(R.id.lvHeaderTipsTv);        lvHeaderLastUpdatedTv = (TextView) headerView.findViewById(R.id.lvHeaderLastUpdatedTv);        lvHeaderArrowIv = (ImageView) headerView.findViewById(R.id.lvHeaderArrowIv);        //设置下拉刷新图标的最小宽度跟高度        lvHeaderArrowIv.setMinimumWidth(70);        lvHeaderArrowIv.setMinimumHeight(50);        lvHeaderProgressBar = (ProgressBar) headerView.findViewById(R.id.lvHeaderProgressBar);        measureView(headerView);        headerContentHeight = headerView.getMeasuredHeight();        //设置内边距，正好距离顶部为一个负的整个布局的高度，正好把头部隐藏        headerView.setPadding(0, -1 * headerContentHeight, 0, 0);        //重绘一下        headerView.invalidate();        //将下拉刷新布局加入到list的顶部        addHeaderView(headerView, null, false);        //设置监听滚动事件        setOnScrollListener(this);        //设置动画        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);        animation.setInterpolator(new LinearInterpolator());        animation.setDuration(200);        animation.setFillAfter(true);        //一开始的状态就是下拉刷新的状态，所以DONE        state = DONE;        //是否正在刷新        isRefreshable = false;    }    @Override    public void onScrollStateChanged(AbsListView view, int scrollState)    {    }    @Override    public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount)    {        if (firstVisibleItem == 0) {            isRefreshable = true;        } else {            isRefreshable = false;        }    }    @Override    public boolean onTouchEvent(MotionEvent ev)    {        if (isRefreshable) {            switch (ev.getAction()) {                case MotionEvent.ACTION_DOWN:                    if (!isRecored) {                        isRecored = true;                        startY = (int) ev.getY();// 手指按下时记录当前位置                    }                    break;                case MotionEvent.ACTION_UP:                    if (state != REFRESHING && state != LOADING) {                        if (state == PULL_To_REFRESH) {                            state = DONE;                            changeHeaderViewByState();                        }                        if (state == RELEASE_To_REFRESH) {                            state = REFRESHING;                            changeHeaderViewByState();                            onLvRefresh();                        }                    }                    isRecored = false;                    isBack = false;                    break;                case MotionEvent.ACTION_MOVE:                    int tempY = (int) ev.getY();                    if (!isRecored) {                        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 < headerContentHeight)// 由松开刷新状态转变到下拉刷新状态                                    && (tempY - startY) > 0) {                                state = PULL_To_REFRESH;                                changeHeaderViewByState();                            }                            // 一下子推到顶了                            else if (tempY - startY <= 0) {// 由松开刷新状态转变到done状态                                state = DONE;                                changeHeaderViewByState();                            }                        }                        // 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 >= headerContentHeight) {// 由done或者下拉刷新状态转变到松开刷新                                state = RELEASE_To_REFRESH;                                isBack = true;                                changeHeaderViewByState();                            }                            // 上推到顶了                            else if (tempY - startY <= 0) {// 由DOne或者下拉刷新状态转变到done状态                                state = DONE;                                changeHeaderViewByState();                            }                        }                        // 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) {                            headerView.setPadding(0, -1 * headerContentHeight                                    + (tempY - startY) / RATIO, 0, 0);                        }                        // 更新headView的paddingTop                        if (state == RELEASE_To_REFRESH) {                            headerView.setPadding(0, (tempY - startY) / RATIO                                    - headerContentHeight, 0, 0);                        }                    }                    break;                default:                    break;            }        }        return super.onTouchEvent(ev);    }    //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:                lvHeaderArrowIv.setVisibility(View.VISIBLE);                lvHeaderProgressBar.setVisibility(View.GONE);                lvHeaderTipsTv.setVisibility(View.VISIBLE);                lvHeaderLastUpdatedTv.setVisibility(View.VISIBLE);                lvHeaderArrowIv.clearAnimation();//清除动画                lvHeaderArrowIv.startAnimation(animation);//开始动画效果                lvHeaderTipsTv.setText("松开刷新");                break;            case PULL_To_REFRESH:                lvHeaderProgressBar.setVisibility(View.GONE);                lvHeaderTipsTv.setVisibility(View.VISIBLE);                lvHeaderLastUpdatedTv.setVisibility(View.VISIBLE);                lvHeaderArrowIv.clearAnimation();                lvHeaderArrowIv.setVisibility(View.VISIBLE);                if (isBack) {                    isBack = false;                    lvHeaderArrowIv.clearAnimation();                    lvHeaderArrowIv.startAnimation(reverseAnimation);                    lvHeaderTipsTv.setText("下拉刷新");                } else {                    lvHeaderTipsTv.setText("下拉刷新");                }                break;            case REFRESHING:                headerView.setPadding(0, 0, 0, 0);                lvHeaderProgressBar.setVisibility(View.VISIBLE);                lvHeaderArrowIv.clearAnimation();                lvHeaderArrowIv.setVisibility(View.GONE);                lvHeaderTipsTv.setText("正在刷新...");                lvHeaderLastUpdatedTv.setVisibility(View.VISIBLE);                break;            case DONE:                headerView.setPadding(0, -1 * headerContentHeight, 0, 0);                lvHeaderProgressBar.setVisibility(View.GONE);                lvHeaderArrowIv.clearAnimation();                lvHeaderArrowIv.setImageResource(R.drawable.ic_action_favor_on_pressed);                lvHeaderTipsTv.setText("下拉刷新");                lvHeaderLastUpdatedTv.setVisibility(View.VISIBLE);                break;        }    }    //对于headView宽高处理    private void measureView(View child)    {        ViewGroup.LayoutParams params = child.getLayoutParams();        if (params == null) {            params = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);        }        int childWidthSpec = ViewGroup.getChildMeasureSpec(0, 0 + 0, params.width);        int lpHeight = params.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 setonRefreshListener(OnRefreshListener refreshListener)    {        this.refreshListener = refreshListener;        isRefreshable = true;    }    public interface OnRefreshListener    {        public void OnRefresh();    }    public void onRefreshComplete()    {        state = DONE;        lvHeaderLastUpdatedTv.setText("最近更新:" + new Date().toLocaleString());        changeHeaderViewByState();    }    private void onLvRefresh()    {        if (refreshListener != null) {            refreshListener.OnRefresh();        }    }    @Override    public void setAdapter(ListAdapter adapter)    {        lvHeaderLastUpdatedTv.setText("最近更新：" + new Date().toLocaleString());        super.setAdapter(adapter);    }}

适配器：

public class LvAdapter extends BaseAdapter {      private List<String> list;      private Context context;      public LvAdapter(List<String> list, Context context) {          this.list = list;          this.context = context;      }      @Override      public int getCount() {          return list.size();      }      @Override      public Object getItem(int position) {          return list.get(position);      }      @Override      public long getItemId(int position) {          return position;      }      @Override      public View getView(int position, View convertView, ViewGroup parent) {          TextView tv = new TextView(context.getApplicationContext());          tv.setText(list.get(position));          return tv;      }  }  

接下来在activity调用：

public class MainActivity extends Activity {      private List<String> list;      private MyListView lv;      private LvAdapter adapter;      @Override      protected void onCreate(Bundle savedInstanceState) {          super.onCreate(savedInstanceState);          setContentView(R.layout.activity_main);          lv = (MyListView) findViewById(R.id.lv);          list = new ArrayList<String>();          list.add("loonggg");          list.add("listView下拉刷新~~");           list.add("listView下拉刷新~~");         list.add("listView下拉刷新~~");         list.add("listView下拉刷新~~");         list.add("listView下拉刷新~~");         list.add("listView下拉刷新~~");         adapter = new LvAdapter(list, this);          lv.setAdapter(adapter);          lv.setonRefreshListener(new OnRefreshListener() {              @Override              public void onRefresh() {                  new AsyncTask<Void, Void, Void>() {                      protected Void doInBackground(Void... params) {                          try {                              Thread.sleep(1000);                          } catch (Exception e) {                              e.printStackTrace();                          }                          list.add("刷新后添加的内容");                          return null;                      }                      @Override                      protected void onPostExecute(Void result) {                          adapter.notifyDataSetChanged();                          lv.onRefreshComplete();                      }                  }.execute(null, null, null);              }          });      }  }  

我这里只做了个下拉刷新，上拉刷新原理差不多。

还有今天是七夕啊，祝程序猿们七夕快乐，小鹏也放弃了女朋友，特地大晚上还来发博客，看到的关注一下~~