Android自定义ListView实现下拉刷新列表
效果图:
下面看一下实现过程:
主Activity:
自定义的ListView:
package com.example.pulltorefreshlistview; import java.util.Date; import android.content.Context; import android.graphics.Color; 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 AlexListView extends ListView implements OnScrollListener { private static final String TAG = "PullToRefreshListView"; private final static int RELEASE_TO_REFRESH = 0; // 松开刷新 private final static int PULL_TO_REFRESH = 1; // 下拉刷新 private final static int REFRESHING = 2; // 刷新中 private final static int DONE = 3; // 完成 private final static int LOADING = 4; // 加载中 // 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的头部 用于显示刷新的箭头等 private LinearLayout headView; private TextView tipsTextview; private TextView lastUpdatedTextView; private ImageView arrowImageView; private ProgressBar progressBar; // 箭头旋转的动画 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 AlexListView(Context context) { super(context); init(context); } public AlexListView(Context context, AttributeSet attrs) { super(context, attrs); init(context); } private void init(Context context) { // setCacheColorHint(context.getResources().getColor(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.e("size", "width:" + headContentWidth + " height:" + headContentHeight); addHeaderView(headView, null, false); setOnScrollListener(this); // {@ TChip ZJ:逆时针旋转180度 @} 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); // {@ TChip ZJ:顺时针旋转180度 @} 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; } @Override public void onScroll(AbsListView arg0, int firstVisiableItem, int arg2, int arg3) { firstItemIndex = firstVisiableItem; } @Override public void onScrollStateChanged(AbsListView arg0, int arg1) { } @Override public boolean onTouchEvent(MotionEvent event) { if (isRefreshable) { switch (event.getAction()) { case MotionEvent.ACTION_DOWN: if (firstItemIndex == 0 && !isRecored) { isRecored = true; // {@ TChip ZJ:记录下down事件的y位置 @} startY = (int) event.getY(); Log.e(TAG, "MotionEvent.ACTION_DOWN"); } 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.e(TAG, "state == PULL_TO_REFRESH"); } if (state == RELEASE_TO_REFRESH) { state = REFRESHING; changeHeaderViewByState(); onRefresh(); Log.e(TAG, "state == RELEASE_TO_REFRESH"); } } isRecored = false; isBack = false; break; case MotionEvent.ACTION_MOVE: int tempY = (int) event.getY(); if (!isRecored && firstItemIndex == 0) { Log.e(TAG, "MotionEvent.ACTION_MOVE"); 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.e(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.e(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.e(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.e(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("放开以刷新"); Log.e(TAG, "State-->RELEASE_TO_REFRESH"); 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.e(TAG, "State-->PULL_TO_REFRESH"); 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.e(TAG, "State-->REFRESHING"); break; case DONE: headView.setPadding(0, -1 * headContentHeight, 0, 0); progressBar.setVisibility(View.GONE); arrowImageView.clearAnimation(); arrowImageView.setImageResource(R.drawable.ic_launcher); tipsTextview.setText("下拉刷新"); lastUpdatedTextView.setVisibility(View.VISIBLE); Log.e(TAG, "State-->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) { // {@ TChip ZJ:设置Header中最近更新时间 @} lastUpdatedTextView.setText("最近更新:" + new Date().toLocaleString()); super.setAdapter(adapter); } }
转载请注明出处:周木水的CSDN博客 http://blog.csdn.net/zhoumushui
我的GitHub:周木水的GitHub https://github.com/zhoumushui
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