Android刷新加载框架详解

本文实例为大家分享了Android刷新加载框架的具体代码，供大家参考，具体内容如下

1.定义一个接口控制下拉和上拉

public interface Pullable {  /**   * 是否可下拉   */  boolean canPullDown();  /**   * 是否可上拉   */  boolean canPullUp();}

2.定义一个刷新加载布局

public class PullToRefreshLayout extends RelativeLayout {  /**   * 头   */  private View headView;//头视图  private ImageView headIv;//头图标  private TextView headTv;//头文字  private int headHeight;//头高度  private float headBorder;//头临界  /**   * 拉   */  private View pullView;//拉视图  private int pullHeight;//拉高度  private int pullWidth;//拉宽度  /**   * 尾   */  private View footView;//尾视图  private ImageView footIv;//尾图标  private TextView footTv;//尾文字  private int footHeight;//尾高度  private float footBorder;//尾临界  /**   * 状态   */  public static final int INIT = 0;//初始  public static final int RELEASE_TO_REFRESH = 1;//释放刷新  public static final int REFRESHING = 2;//正在刷新  public static final int RELEASE_TO_LOAD = 3;//释放加载  public static final int LOADING = 4;//正在加载  public static final int DONE = 5;//完成  private int state = INIT;  /**   * 接口   */  private OnRefreshListener mListener;  private float downY;//按下时Y坐标  private float lastY;//上一个Y坐标  private float pullDownY = 0;//下拉偏移量  private float pullUpY = 0;//上拉偏移量  private int offset;//偏移量  /**   * 动画   */  private RotateAnimation rotateAnimation;  /**   * 线程   */  private Handler handler = new Handler() {    @Override    public void handleMessage(Message msg) {      super.handleMessage(msg);      if (msg != null) {        switch (msg.what) {          case 1:            headIv.clearAnimation();            break;          case 2:            footIv.clearAnimation();            break;          default:            break;        }        pullDownY = 0;        pullUpY = 0;        requestLayout();        state = INIT;        refreshViewByState();        isTouch = true;      }    }  };  /**   * 第一次执行布局   */  private boolean isLayout = false;  /**   * 在刷新过程中滑动操作   */  private boolean isTouch = false;  /**   * 手指滑动距离与下拉头的滑动距离比，中间会随正切函数变化   */  private float radio = 2;  /**   * 过滤多点触碰   */  private int mEvents;  /**   * 这两个变量用来控制pull的方向，如果不加控制，当情况满足可上拉又可下拉时没法下拉   */  private boolean canPullDown = true;  private boolean canPullUp = true;  public void setOnRefreshListener(OnRefreshListener listener) {    mListener = listener;  }  public PullToRefreshLayout(Context context) {    super(context);    initView(context);  }  public PullToRefreshLayout(Context context, AttributeSet attrs) {    super(context, attrs);    initView(context);  }  public PullToRefreshLayout(Context context, AttributeSet attrs, int defStyle) {    super(context, attrs, defStyle);    initView(context);  }  private void initView(Context context) {    rotateAnimation = (RotateAnimation) AnimationUtils.loadAnimation(context, R.anim.rotating);  }  private void refreshViewByState() {    switch (state) {      case INIT:        // 下拉布局初始状态        headIv.setImageResource("下拉刷新显示的图片");        headTv.setText("下拉刷新");        // 上拉布局初始状态        footIv.setImageResource("上拉加载显示的图片");        footTv.setText("上拉加载");        break;      case RELEASE_TO_REFRESH:        // 释放刷新状态        headIv.setImageResource("释放刷新显示的图片");        headTv.setText("释放刷新");        break;      case REFRESHING:        // 正在刷新状态        headIv.setImageResource("正在刷新显示的图片");        headTv.setText("正在刷新");        break;      case RELEASE_TO_LOAD:        // 释放加载状态        footIv.setImageResource("释放加载显示的图片");        footTv.setText("释放加载");        break;      case LOADING:        // 正在加载状态        footIv.setImageResource("正在加载显示的图片");        footTv.setText("正在加载");        break;      case DONE:        // 刷新或加载完毕，啥都不做        break;    }  }  /**   * 不限制上拉或下拉   */  private void releasePull() {    canPullDown = true;    canPullUp = true;  }    @Override  public boolean dispatchTouchEvent(MotionEvent ev) {    switch (ev.getActionMasked()) {      case MotionEvent.ACTION_DOWN:        downY = ev.getY();        lastY = downY;        mEvents = 0;        releasePull();        if (state != REFRESHING && state != LOADING) {          isTouch = true;        }        break;      case MotionEvent.ACTION_POINTER_DOWN:      case MotionEvent.ACTION_POINTER_UP:        // 过滤多点触碰        mEvents = -1;        break;      case MotionEvent.ACTION_MOVE:        if (mEvents == 0) {          if (pullDownY > 0 || (((Pullable) pullView).canPullDown()              && canPullDown && state != LOADING && state != REFRESHING)) {            // 可以下拉，正在加载时不能下拉            // 对实际滑动距离做缩小，造成用力拉的感觉            pullDownY = pullDownY + (ev.getY() - lastY) / radio;            if (pullDownY < 0) {              pullDownY = 0;              canPullDown = false;              canPullUp = true;            }            if (pullDownY > getMeasuredHeight()) {              pullDownY = getMeasuredHeight();            }            if (state == REFRESHING) {              // 正在刷新的时候触摸移动              isTouch = false;            }          } else if (pullUpY < 0              || (((Pullable) pullView).canPullUp() && canPullUp && state != REFRESHING && state != LOADING)) {            // 可以上拉，正在刷新时不能上拉            pullUpY = pullUpY + (ev.getY() - lastY) / radio;            if (pullUpY > 0) {              pullUpY = 0;              canPullDown = true;              canPullUp = false;            }            if (pullUpY < -getMeasuredHeight()) {              pullUpY = -getMeasuredHeight();            }            if (state == LOADING) {              // 正在加载的时候触摸移动              isTouch = false;            }          }        }        if (isTouch) {          lastY = ev.getY();          if (pullDownY > 0 || pullUpY < 0) {            requestLayout();          }          if (pullDownY > 0) {            if (pullDownY <= headBorder && (state == RELEASE_TO_REFRESH || state == DONE)) {              // 如果下拉距离没达到刷新的距离且当前状态是释放刷新，改变状态为下拉刷新              state = INIT;              refreshViewByState();            }            if (pullDownY >= headBorder && state == INIT) {              // 如果下拉距离达到刷新的距离且当前状态是初始状态刷新，改变状态为释放刷新              state = RELEASE_TO_REFRESH;              refreshViewByState();            }          } else if (pullUpY < 0) {            // 下面是判断上拉加载的，同上，注意pullUpY是负值            if (-pullUpY <= footBorder && (state == RELEASE_TO_LOAD || state == DONE)) {              state = INIT;              refreshViewByState();            }            // 上拉操作            if (-pullUpY >= footBorder && state == INIT) {              state = RELEASE_TO_LOAD;              refreshViewByState();            }          }          // 因为刷新和加载操作不能同时进行，所以pullDownY和pullUpY不会同时不为0，因此这里用(pullDownY +          // Math.abs(pullUpY))就可以不对当前状态作区分了          if ((pullDownY + Math.abs(pullUpY)) > 8) {            // 防止下拉过程中误触发长按事件和点击事件            ev.setAction(MotionEvent.ACTION_CANCEL);          }        }        break;      case MotionEvent.ACTION_UP:        if (pullDownY > headBorder || -pullUpY > footBorder) {          // 正在刷新时往下拉（正在加载时往上拉），释放后下拉头（上拉头）不隐藏          isTouch = false;        }        if (state == RELEASE_TO_REFRESH) {          state = REFRESHING;          refreshViewByState();          // 刷新操作          if (mListener != null) {            canPullDown = false;            pullDownY = headBorder;            pullUpY = 0;            requestLayout();            headIv.startAnimation(rotateAnimation);            mListener.onRefresh(this);          }        } else if (state == RELEASE_TO_LOAD) {          state = LOADING;          refreshViewByState();          // 加载操作          if (mListener != null) {            canPullUp = false;            pullDownY = 0;            pullUpY = -footBorder;            requestLayout();            footIv.startAnimation(rotateAnimation);            mListener.onLoadMore(this);          }        } else {          pullDownY = 0;          pullUpY = 0;          requestLayout();        }      default:        break;    }    // 事件分发交给父类    super.dispatchTouchEvent(ev);    return true;  }  public void hideHeadView() {    handler.sendEmptyMessage(1);  }  public void hideFootView() {    handler.sendEmptyMessage(2);  }  private void initView() {    // 初始化下拉布局    headIv = (ImageView) headView.findViewById(R.id.iv_head);    headTv = (TextView) headView.findViewById(R.id.tv_head);    //初始化上拉布局    footIv = (ImageView) footView.findViewById(R.id.iv_foot);    footTv = (TextView) footView.findViewById(R.id.tv_foot);    refreshViewByState();  }  @Override  protected void onLayout(boolean changed, int l, int t, int r, int b) {    if (!isLayout) {      // 这里是第一次进来的时候做一些初始化      headView = getChildAt(0);      pullView = getChildAt(1);      footView = getChildAt(2);      headBorder = ((ViewGroup) headView).getChildAt(0).getMeasuredHeight();      footBorder = ((ViewGroup) footView).getChildAt(0).getMeasuredHeight();      headHeight = headView.getMeasuredHeight();      pullHeight = pullView.getMeasuredHeight();      footHeight = footView.getMeasuredHeight();      pullWidth = pullView.getMeasuredWidth();      initView();      isLayout = true;    }    // 改变子控件的布局，这里直接用(pullDownY + pullUpY)作为偏移量，这样就可以不对当前状态作区分    offset = (int) (pullDownY + pullUpY);    headView.layout(0, -headHeight + offset, pullWidth, offset);    pullView.layout(0, offset, pullWidth, pullHeight + offset);    footView.layout(0, pullHeight + offset, pullWidth, pullHeight + footHeight + offset);  }  public interface OnRefreshListener {    void onRefresh(PullToRefreshLayout pullToRefreshLayout);    void onLoadMore(PullToRefreshLayout pullToRefreshLayout);  }}

3.自定义View
ListView

public class PullableListView extends ListView implements Pullable {  public PullableListView(Context context) {    super(context);  }  public PullableListView(Context context, AttributeSet attrs) {    super(context, attrs);  }  public PullableListView(Context context, AttributeSet attrs, int defStyle) {    super(context, attrs, defStyle);  }  @Override  public boolean canPullDown() {    if (getCount() == 0) {      // 没有item的时候也可以下拉刷新      return false;    } else if (getFirstVisiblePosition() == 0 && getChildAt(0).getTop() >= 0) {      // 滑到ListView的顶部了      return true;    } else      return false;  }  @Override  public boolean canPullUp() {    if (getCount() == 0) {      // 没有item的时候也可以上拉加载      return false;    } else if (getLastVisiblePosition() == (getCount() - 1)) {      // 滑到底部了      if (getChildAt(getLastVisiblePosition() - getFirstVisiblePosition()) != null          && getChildAt(getLastVisiblePosition() - getFirstVisiblePosition())          .getBottom() <= getMeasuredHeight())        return true;    }    return false;  }}

GridView

public class PullableGridView extends GridView implements Pullable {  public PullableGridView(Context context) {    super(context);  }  public PullableGridView(Context context, AttributeSet attrs) {    super(context, attrs);  }  public PullableGridView(Context context, AttributeSet attrs, int defStyle) {    super(context, attrs, defStyle);  }  @Override  public boolean canPullDown() {    if (getCount() == 0) {      // 没有item的时候也可以下拉刷新      return false;    } else if (getFirstVisiblePosition() == 0        && getChildAt(0).getTop() >= 0) {      // 滑到顶部了      return true;    } else      return false;  }  @Override  public boolean canPullUp() {    if (getCount() == 0) {      // 没有item的时候也可以上拉加载      return false;    } else if (getLastVisiblePosition() == (getCount() - 1)) {      // 滑到底部了      if (getChildAt(getLastVisiblePosition() - getFirstVisiblePosition()) != null          && getChildAt(          getLastVisiblePosition()              - getFirstVisiblePosition()).getBottom() <= getMeasuredHeight())        return true;    }    return false;  }}

RecyclerView

public class PullableRecyclerView extends RecyclerView implements Pullable {  public PullableRecyclerView(Context context) {    super(context);  }  public PullableRecyclerView(Context context, @Nullable AttributeSet attrs) {    super(context, attrs);  }  public PullableRecyclerView(Context context, @Nullable AttributeSet attrs, int defStyle) {    super(context, attrs, defStyle);  }  @Override  public boolean canPullDown() {    RecyclerView.LayoutManager layoutManager = getLayoutManager();    if (layoutManager instanceof LinearLayoutManager) {      LinearLayoutManager linearLayoutManager = (LinearLayoutManager) layoutManager;      if (linearLayoutManager.getItemCount() == 0) {        return false;      } else if (linearLayoutManager.findFirstVisibleItemPosition() == 0 && linearLayoutManager.getChildAt(0).getTop() >= 0) {        return true;      } else {        return false;      }    } else if (layoutManager instanceof StaggeredGridLayoutManager) {      StaggeredGridLayoutManager staggeredGridLayoutManager = (StaggeredGridLayoutManager) layoutManager;      if (staggeredGridLayoutManager.getItemCount() == 0) {        return false;      } else {        int[] firstVisibleItems = null;        firstVisibleItems = staggeredGridLayoutManager.findFirstVisibleItemPositions(firstVisibleItems);        if (firstVisibleItems != null && firstVisibleItems.length > 0) {          if (staggeredGridLayoutManager.getChildCount() + firstVisibleItems[0] == staggeredGridLayoutManager.getItemCount()) {            return true;          }        }      }    }    return false;  }  @Override  public boolean canPullUp() {    RecyclerView.LayoutManager layoutManager = getLayoutManager();    if (layoutManager instanceof LinearLayoutManager) {      LinearLayoutManager linearLayoutManager = (LinearLayoutManager) layoutManager;      if (linearLayoutManager.getItemCount() == 0) {        return false;      } else if (linearLayoutManager.findLastVisibleItemPosition() == (linearLayoutManager.getItemCount() - 1)) {        if (linearLayoutManager.getChildAt(linearLayoutManager.findLastVisibleItemPosition() - linearLayoutManager.findFirstVisibleItemPosition()) != null            && linearLayoutManager.getChildAt(linearLayoutManager.findLastVisibleItemPosition() - linearLayoutManager.findFirstVisibleItemPosition()).getBottom() <= getMeasuredHeight()) {          return true;        }      }    } else if (layoutManager instanceof StaggeredGridLayoutManager) {      StaggeredGridLayoutManager staggeredGridLayoutManager = (StaggeredGridLayoutManager) layoutManager;      if (staggeredGridLayoutManager.getItemCount() == 0) {        return false;      } else {        int[] lastPositions = new int[staggeredGridLayoutManager.getSpanCount()];        lastPositions = staggeredGridLayoutManager.findLastVisibleItemPositions(lastPositions);        if (findMax(lastPositions) >= staggeredGridLayoutManager.getItemCount() - 1) {          return true;        }      }    }    return false;  }  private int findMax(int[] lastPositions) {    int max = lastPositions[0];    for (int value : lastPositions) {      if (value > max) {        max = value;      }    }    return max;  }}

ExpandableListView

public class PullableExpandableListView extends ExpandableListView implements    Pullable {  public PullableExpandableListView(Context context) {    super(context);  }  public PullableExpandableListView(Context context, AttributeSet attrs) {    super(context, attrs);  }  public PullableExpandableListView(Context context, AttributeSet attrs,                   int defStyle) {    super(context, attrs, defStyle);  }  @Override  public boolean canPullDown() {    if (getCount() == 0) {      // 没有item的时候也可以下拉刷新      return false;    } else if (getFirstVisiblePosition() == 0        && getChildAt(0).getTop() >= 0) {      // 滑到顶部了      return true;    } else      return false;  }  @Override  public boolean canPullUp() {    if (getCount() == 0) {      // 没有item的时候也可以上拉加载      return false;    } else if (getLastVisiblePosition() == (getCount() - 1)) {      // 滑到底部了      if (getChildAt(getLastVisiblePosition() - getFirstVisiblePosition()) != null          && getChildAt(          getLastVisiblePosition()              - getFirstVisiblePosition()).getBottom() <= getMeasuredHeight())        return true;    }    return false;  }}

ScrollView

public class PullableScrollView extends ScrollView implements Pullable {  public PullableScrollView(Context context) {    super(context);  }  public PullableScrollView(Context context, AttributeSet attrs) {    super(context, attrs);  }  public PullableScrollView(Context context, AttributeSet attrs, int defStyle) {    super(context, attrs, defStyle);  }  @Override  public boolean canPullDown() {    if (getScrollY() == 0)      return true;    else      return false;  }  @Override  public boolean canPullUp() {    if (getScrollY() >= (getChildAt(0).getHeight() - getMeasuredHeight()))      return true;    else      return false;  }}

WebView

 public class PullableWebView extends WebView implements Pullable {  public PullableWebView(Context context) {    super(context);  }  public PullableWebView(Context context, AttributeSet attrs) {    super(context, attrs);  }  public PullableWebView(Context context, AttributeSet attrs, int defStyle) {    super(context, attrs, defStyle);  }  @Override  public boolean canPullDown() {    if (getScrollY() == 0)      return true;    else      return false;  }  @Override  public boolean canPullUp() {    if (getScrollY() >= getContentHeight() * getScale()        - getMeasuredHeight())      return true;    else      return false;  }}

ImageView

public class PullableImageView extends ImageView implements Pullable{  public PullableImageView(Context context)  {    super(context);  }  public PullableImageView(Context context, AttributeSet attrs)  {    super(context, attrs);  }  public PullableImageView(Context context, AttributeSet attrs, int defStyle)  {    super(context, attrs, defStyle);  }  @Override  public boolean canPullDown()  {    return true;  }  @Override  public boolean canPullUp()  {    return true;  }}

TextView

public class PullableTextView extends TextView implements Pullable {  public PullableTextView(Context context) {    super(context);  }  public PullableTextView(Context context, AttributeSet attrs) {    super(context, attrs);  }  public PullableTextView(Context context, AttributeSet attrs, int defStyle) {    super(context, attrs, defStyle);  }  @Override  public boolean canPullDown() {    return true;  }  @Override  public boolean canPullUp() {    return true;  }}

4.使用示例(以ListView为例)

head

<?xml version="1.0" encoding="UTF-8"?>

foot

<?xml version="1.0" encoding="UTF-8"?>

4.注意

自定义的View跟正常的View的使用没有什么差别
如需实现刷新加载，必须使ptrl.setOnRefreshListener(PullToRefreshLayout.OnRefreshListener onRefreshListener);

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。

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