Android 仿新浪微博的ListView下拉更新功能

openkk 12年前

           由于最近做的项目中也用到了这个功能,今天刚好实现了下,就趁现在有时间写篇博客分享下。在做的时候也参考了下别人的代码,毕竟站在巨人的肩膀上才会是自己更加强大。哈哈!先看看新浪的下拉更新是什么样的吧!

        Android 仿新浪微博的ListView下拉更新功能

      OK,今天我们要实现的就是上面的下拉刷新功能。

      首先实现下拉刷新的布局文件 layout/head.xml

<?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="#ffffff"   >        <!-- 内容 -->    <RelativeLayout    android:layout_width="fill_parent"    android:layout_height="wrap_content"    android:id="@+id/head_contentLayout"    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:layout_width="wrap_content"    android:layout_height="wrap_content"    android:layout_gravity="center"    android:src="@drawable/arrow_down"    android:id="@+id/head_arrowImageView"    />        <!-- 进度条 -->    <ProgressBar    android:layout_width="wrap_content"    android:layout_height="wrap_content"    style="?android:attr/progressBarStyleSmall"    android:layout_gravity="center"    android:id="@+id/head_progressBar"        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:orientation="vertical"    android:gravity="center_horizontal"    >        <!-- 提示 -->    <TextView    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:text="下拉刷新"    android:textSize="15dp"    android:id="@+id/head_tipsTextView"    />        <!-- 最近更新 -->    <TextView    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:id="@+id/head_lastUpdatedTextView"    android:text="上次更新"    android:textSize="12dp"    />        </LinearLayout>            </RelativeLayout>          </LinearLayout>
然后设置item的布局模板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="wrap_content"      android:gravity="center_vertical"      android:background="#ffffff"      android:orientation="horizontal" >        <ImageView          android:id="@+id/imageView_item"          android:layout_width="wrap_content"          android:layout_height="wrap_content"          android:layout_marginLeft="10dp"          android:src="@drawable/ic_launcher" />        <TextView          android:id="@+id/textView_item"          android:layout_width="wrap_content"          android:layout_height="wrap_content"          android:layout_marginLeft="10dp"          android:text="TextView" />    </LinearLayout>
     接下来是main.xml布局:
<?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" >            <cn.com.karl.list.MyListView      android:layout_width="fill_parent"      android:layout_height="fill_parent"      android:id="@+id/listView"      />          </LinearLayout>
   这里的MyListView是我们自定义的ListView,因为顶部的下拉刷新系统的ListView不能够实现,所以我们需要自定义ListView。

   布局文件搞定,下面看下自定义的MyListView:

package cn.com.karl.list;    import java.text.SimpleDateFormat;  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.BaseAdapter;  import android.widget.ImageView;  import android.widget.LinearLayout;  import android.widget.ListView;  import android.widget.AbsListView.OnScrollListener;  import android.widget.ProgressBar;  import android.widget.TextView;    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) {    //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;   }     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_down);     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 format=new SimpleDateFormat("yyyy年MM月dd日  HH:mm");    String date=format.format(new Date());    lastUpdatedTextView.setText("最近更新:" + 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   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) {    SimpleDateFormat format=new SimpleDateFormat("yyyy年MM月dd日  HH:mm");    String date=format.format(new Date());    lastUpdatedTextView.setText("最近更新:" + date);    super.setAdapter(adapter);   }       }
最后在MainActivity中添加内容:
public class MainActivity extends Activity {     private LinkedList<String> data;   private BaseAdapter adapter;     public void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.main);      data = new LinkedList<String>();       for(int i=0;i<10;i++){        data.add(String.valueOf(i));       }      final MyListView listView = (MyListView) findViewById(R.id.listView);    adapter = new BaseAdapter() {     public View getView(int position, View convertView, ViewGroup parent) {       convertView=LayoutInflater.from(getApplicationContext()).inflate(R.layout.item, null);      TextView textView = (TextView) convertView.findViewById(R.id.textView_item);      textView.setText(data.get(position));      return convertView;     }       public long getItemId(int position) {      return position;     }       public Object getItem(int position) {      return data.get(position);     }       public int getCount() {      return data.size();     }    };    listView.setAdapter(adapter);      listView.setonRefreshListener(new OnRefreshListener() {     public void onRefresh() {      new AsyncTask<Void, Void, Void>() {       protected Void doInBackground(Void... params) {        try {         Thread.sleep(1000);        } catch (Exception e) {         e.printStackTrace();        }        data.addFirst("刷新后的内容");        return null;       }         @Override       protected void onPostExecute(Void result) {        adapter.notifyDataSetChanged();        listView.onRefreshComplete();       }        }.execute(null);     }    });   }  }
    运行效果:

Android 仿新浪微博的ListView下拉更新功能

 

 

Android 仿新浪微博的ListView下拉更新功能

   转自:http://blog.csdn.net/wangkuifeng0118/article/details/7463594