安卓中級教程（5）：ScrollView與refreshable之間的設置

設置向下拉動更新。

 package com.mycompany.Scroll_test;

 import android.app.*;
 import android.os.*;
 import android.view.*;
 import android.widget.*;

 /**
  * 刷新控制view
  *
  * @author Nono
  *
  */
 public class RefreshableView extends LinearLayout {

     private static final String TAG = "LILITH";
     private Scroller scroller;
     private View refreshView;
     private ImageView refreshIndicatorView;
     private int refreshTargetTop = -60;
     private ProgressBar bar;
     private TextView downTextView;
     private TextView timeTextView;

     private RefreshListener refreshListener;

     private String downTextString;
     private String releaseTextString;

     private Long refreshTime = null;
     private int lastX;
     private int lastY;
     // 拉動標記
     private boolean isDragging = false;
     // 是否可刷新標記
     private boolean isRefreshEnabled = true;
     // 在刷新中標記
     private boolean isRefreshing = false;

     private Context mContext;
     public RefreshableView(Context context) {
         super(context);
         mContext = context;

     }
     public RefreshableView(Context context, AttributeSet attrs) {
         super(context, attrs);
         mContext = context;
         init();

     }
     private void init() {
         // TODO Auto-generated method stub
         //滑動對象，
         scroller = new Scroller(mContext);

         //刷新視圖頂端的的view
         refreshView = LayoutInflater.from(mContext).inflate(R.layout.refresh_top_item, null);
         //指示器view
         refreshIndicatorView = (ImageView) refreshView.findViewById(R.id.indicator);
         //刷新bar
         bar = (ProgressBar) refreshView.findViewById(R.id.progress);
         //下拉顯示text
         downTextView = (TextView) refreshView.findViewById(R.id.refresh_hint);
         //下來顯示時間
         timeTextView = (TextView) refreshView.findViewById(R.id.refresh_time);

         LayoutParams lp = new LinearLayout.LayoutParams(LayoutParams.FILL_PARENT, -refreshTargetTop);
         lp.topMargin = refreshTargetTop;
         lp.gravity = Gravity.CENTER;
         addView(refreshView, lp);
         downTextString = mContext.getResources().getString(R.string.refresh_down_text);
         releaseTextString = mContext.getResources().getString(R.string.refresh_release_text);
     }

     /**
      * 刷新
      * @param time
      */
     private void setRefreshText(String time) {
         // TODO Auto-generated method stub
         //timeTextView.setText(time);
     }

     @Override
     public boolean onTouchEvent(MotionEvent event) {

         int y= (int) event.getRawY();

         switch (event.getAction()) {
             case MotionEvent.ACTION_DOWN:
                 //記錄下y坐標
                 lastY = y;
                 break;

             case MotionEvent.ACTION_MOVE:
                 Log.i(TAG, "ACTION_MOVE");
                 //y移動坐標
                 int m = y - lastY;
                 if(((m < 6) && (m > -1)) || (!isDragging )){
                     doMovement(m);
                 }
                 //記錄下此刻y坐標
                 this.lastY = y;
                 break;

             case MotionEvent.ACTION_UP:
                 Log.i(TAG, "ACTION_UP");

                 fling();

                 break;
         }
         return true;
     }

     /**
      * up事件處理
      */
     private void fling() {
         // TODO Auto-generated method stub
         LinearLayout.LayoutParams lp = (LayoutParams) refreshView.getLayoutParams();
         Log.i(TAG, "fling()" + lp.topMargin);
         if(lp.topMargin > 0){//拉到了觸發可刷新事件
             refresh();
         }else{
             returnInitState();
         }
     }

     private void returnInitState() {
         // TODO Auto-generated method stub
         LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams)this.refreshView.getLayoutParams();
         int i = lp.topMargin;
         scroller.startScroll(0, i, 0, refreshTargetTop);
         invalidate();
     }
     private void refresh() {
         // TODO Auto-generated method stub
         LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams)this.refreshView.getLayoutParams();
         int i = lp.topMargin;
         refreshIndicatorView.setVisibility(View.GONE);
         bar.setVisibility(View.VISIBLE);
         timeTextView.setVisibility(View.GONE);
         downTextView.setVisibility(View.GONE);
         scroller.startScroll(0, i, 0, 0-i);
         invalidate();
         if(refreshListener !=null){
             refreshListener.onRefresh(this);
             isRefreshing = true;
         }
     }

     /**
      *
      */
     @Override
     public void computeScroll() {
         // TODO Auto-generated method stub
         if(scroller.computeScrollOffset()){
             int i = this.scroller.getCurrY();
             LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams)this.refreshView.getLayoutParams();
             int k = Math.max(i, refreshTargetTop);
             lp.topMargin = k;
             this.refreshView.setLayoutParams(lp);
             this.refreshView.invalidate();
             invalidate();
         }
     }
     /**
      * 下拉move事件處理
      * @param moveY
      */
     private void doMovement(int moveY) {
         // TODO Auto-generated method stub
         LinearLayout.LayoutParams lp = (LayoutParams) refreshView.getLayoutParams();
         if(moveY > 0){
             //獲取view的上邊距
             float f1 =lp.topMargin;
             float f2 = moveY * 0.3F;
             int i = (int)(f1+f2);
             //修改上邊距
             lp.topMargin = i;
             //修改後刷新
             refreshView.setLayoutParams(lp);
             refreshView.invalidate();
             invalidate();
         }
         timeTextView.setVisibility(View.VISIBLE);
         if(refreshTime!= null){
             setRefreshTime(refreshTime);
         }
         downTextView.setVisibility(View.VISIBLE);

         refreshIndicatorView.setVisibility(View.VISIBLE);
         bar.setVisibility(View.GONE);
         if(lp.topMargin >  0){
             downTextView.setText(R.string.refresh_release_text);
             refreshIndicatorView.setImageResource(R.drawable.refresh_arrow_up);
         }else{
             downTextView.setText(R.string.refresh_down_text);
             refreshIndicatorView.setImageResource(R.drawable.refresh_arrow_down);
         }

     }

     public void setRefreshEnabled(boolean b) {
         this.isRefreshEnabled = b;
     }

     public void setRefreshListener(RefreshListener listener) {
         this.refreshListener = listener;
     }

     /**
      * 刷新時間
      * @param refreshTime2
      */
     private void setRefreshTime(Long time) {
         // TODO Auto-generated method stub

     }

     /**
      * 結束刷新事件
      */
     public void finishRefresh(){
         Log.i(TAG, "執行了=====finishRefresh");
         LinearLayout.LayoutParams lp= (LinearLayout.LayoutParams)this.refreshView.getLayoutParams();
         int i = lp.topMargin;
         refreshIndicatorView.setVisibility(View.VISIBLE);
         timeTextView.setVisibility(View.VISIBLE);
         scroller.startScroll(0, i, 0, refreshTargetTop);
         invalidate();
         isRefreshing = false;
     }

     /*該方法一般和ontouchEvent 一起用
      * (non-Javadoc)
      * @see android.view.ViewGroup#onInterceptTouchEvent(android.view.MotionEvent)
      */
     @Override
     public boolean onInterceptTouchEvent(MotionEvent e) {
         // TODO Auto-generated method stub
         int action = e.getAction();
         int y= (int) e.getRawY();
         switch (action) {
             case MotionEvent.ACTION_DOWN:
                 lastY = y;
                 break;

             case MotionEvent.ACTION_MOVE:
                 //y移動坐標
                 int m = y - lastY;

                 //記錄下此刻y坐標
                 this.lastY = y;
                 if(m > 6 &&  canScroll()){
                     return true;
                 }
                 break;
             case MotionEvent.ACTION_UP:

                 break;

             case MotionEvent.ACTION_CANCEL:

                 break;
         }
         return false;
     }
     private boolean canScroll() {
         // TODO Auto-generated method stub
         View childView;
         if(getChildCount()>1){
             childView = this.getChildAt(1);
             if(childView instanceof ListView){
                 int top =((ListView)childView).getChildAt(0).getTop();
                 int pad =((ListView)childView).getListPaddingTop();
                 if((Math.abs(top-pad)) < 3&&
                    ((ListView) childView).getFirstVisiblePosition() == 0){
                     return true;
                 }else{
                     return false;
                 }
             }else if(childView instanceof ScrollView){
                 if(((ScrollView)childView).getScrollY() == 0){
                     return true;
                 }else{
                     return false;
                 }
             }

         }
         return false;
     }
     /**
      * 刷新監聽接口
      * @author Nono
      *
      */
     public interface RefreshListener{
         public void onRefresh(RefreshableView view);
     }}