RefreshableListView无法强制转换为ListView Error(Pull to Refresh)

Question

我在尝试实现Refreshable Listview时出错。是什么导致了这个错误？我可能忽略了什么。。提前谢谢。

10-10 19:01:28.815 17274-17274/？E/AndroidRuntime﹕致命异常：main java.lang.RuntimeException：无法启动活动组件信息｛nl.rss.foit.myapplication/nl.rss.foit.myapplication.MyActivity｝：java.lang.ClassCastException：android.widget.ListView无法强制转换至nl.rss.foit.myapplication.Refresh.RefreshableListView

可刷新接口.java

public interface RefreshableInterface {
 public void startFresh();
 public void startLoadMore();
}

可刷新列表视图Java

import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.animation.LinearInterpolator;
import android.view.animation.RotateAnimation;
import android.widget.AbsListView;
import android.widget.AbsListView.OnScrollListener;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.RelativeLayout;
import android.widget.TextView;
import java.text.SimpleDateFormat;
import java.util.Date;
import nl.rss.foit.myapplication.R;
public class RefreshableListView extends ListView implements OnScrollListener {
    private final int HEADER_HEIGHT = 60;
    private final int HEADER_TOP = 10;
    private final int STATE_PULL_TO_REFRESH = 0;
    private final int STATE_RELEASE_TO_UPDATE = 1;
    private int currentState;
    private ImageView arrowImage;
    private ProgressBar progressBar;
    private TextView headerTextView;
    private TextView lastUpdateDateTextView;
    private LinearLayout headerRelativeLayout;
    private RotateAnimation rotateAnimation;
    private RotateAnimation reverseRotateAnimation;
    private RefreshableInterface refreshDelegate;
    private RelativeLayout footerLayout;
    private ProgressBar footerProgressBar;
    private boolean isLoadingMore;
    private boolean isLoading;
    //private boolean isDragging;
    private float startY;
    private float deltaY;
   
    public RefreshableListView(Context context) {
        super(context);
        // TODO Auto-generated constructor stub
        init(context);
    }
    public RefreshableListView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init(context);
    }
    @Override
    public void onScroll(AbsListView view, int firstVisibleItem,
                         int visibleItemCount, int totalItemCount) {
        // TODO Auto-generated method stub
        Log.d("debug", "debug");
    }
    @Override
    public void onScrollStateChanged(AbsListView view, int scrollState) {
        // TODO Auto-generated method stub
    }
    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        // TODO Auto-generated method stub
        switch (ev.getAction()) {
            case MotionEvent.ACTION_DOWN:
                //isDragging = true;
                startY = ev.getY();
                break;
            case MotionEvent.ACTION_MOVE:
                if (!isLoading) {
                    deltaY = ev.getY() - startY;
                    Log.d("debug", String.valueOf(deltaY));
                    headerRelativeLayout.setPadding(
                            headerRelativeLayout.getPaddingLeft(), -1
                                    * HEADER_HEIGHT + (int) deltaY, 0,
                            headerRelativeLayout.getPaddingBottom());
                    if(headerRelativeLayout.getPaddingTop() >= HEADER_HEIGHT && currentState == STATE_PULL_TO_REFRESH) {
                        //change state
                        currentState = STATE_RELEASE_TO_UPDATE;
                        arrowImage.clearAnimation();
                        arrowImage.startAnimation(rotateAnimation);
                        headerTextView.setText(R.string.release_to_refresh);
                    } else if (headerRelativeLayout.getPaddingTop() < HEADER_HEIGHT && currentState == STATE_RELEASE_TO_UPDATE) {
                        currentState = STATE_PULL_TO_REFRESH;
                        arrowImage.clearAnimation();
                        arrowImage.startAnimation(reverseRotateAnimation);
                        headerTextView.setText(R.string.pull_to_refresh);
                    }
                }
                break;
            case MotionEvent.ACTION_UP:
                //isDragging = false;
                if (!isLoading) {
                    if (headerRelativeLayout.getPaddingTop() < HEADER_HEIGHT) {
                        // come back
                        headerRelativeLayout.setPadding(
                                headerRelativeLayout.getPaddingLeft(), -1
                                        * HEADER_HEIGHT, 0,
                                headerRelativeLayout.getPaddingBottom());
                    } else {
                        // come to HEADER_HEIGHT and start the trigger
                        headerRelativeLayout.setPadding(
                                headerRelativeLayout.getPaddingLeft(), HEADER_TOP, 0,
                                headerRelativeLayout.getPaddingBottom());
                        headerTextView.setText(R.string.loading);
                        progressBar.setVisibility(View.VISIBLE);
                        arrowImage.clearAnimation();
                        arrowImage.setVisibility(View.GONE);
                        //START LOADING
                        isLoading = true;
                        if (refreshDelegate != null) {
                            refreshDelegate.startFresh();
                        }
                    }
                }
                break;
            default:
                break;
        }
        return super.onTouchEvent(ev);
    }
    private void init(Context context) {
        headerRelativeLayout = (LinearLayout) inflate(context,
                R.layout.refresh_header_view, null);
        arrowImage = (ImageView) headerRelativeLayout
                .findViewById(R.id.head_arrowImageView);
        progressBar = (ProgressBar) headerRelativeLayout
                .findViewById(R.id.head_progressBar);
        headerTextView = (TextView) headerRelativeLayout
                .findViewById(R.id.head_tipsTextView);
        headerTextView.setText(R.string.pull_to_refresh);
        lastUpdateDateTextView = (TextView) headerRelativeLayout
                .findViewById(R.id.head_lastUpdatedDateTextView);
        lastUpdateDateTextView.setText("");
        headerRelativeLayout.setPadding(headerRelativeLayout.getPaddingLeft(),
                -1 * HEADER_HEIGHT, 0, headerRelativeLayout.getPaddingBottom());
        this.addHeaderView(headerRelativeLayout, null, false);
        footerLayout = (RelativeLayout) inflate(context, R.layout.refresh_footer_view, null);
        footerProgressBar = (ProgressBar)footerLayout.findViewById(R.id.footer_progressBar);
        footerLayout.setOnClickListener(loadMoreClickListener);
        this.addFooterView(footerLayout, null, false);
        isLoadingMore = false;
        //isDragging = false;
        currentState = STATE_PULL_TO_REFRESH;
        this.setOnScrollListener(this);
        rotateAnimation = new RotateAnimation(0, -180,
                RotateAnimation.RELATIVE_TO_SELF, 0.5f,
                RotateAnimation.RELATIVE_TO_SELF, 0.5f);
        rotateAnimation.setInterpolator(new LinearInterpolator());
        rotateAnimation.setDuration(250);
        rotateAnimation.setFillAfter(true);
        reverseRotateAnimation = new RotateAnimation(-180, 0,
                RotateAnimation.RELATIVE_TO_SELF, 0.5f,
                RotateAnimation.RELATIVE_TO_SELF, 0.5f);
        reverseRotateAnimation.setInterpolator(new LinearInterpolator());
        reverseRotateAnimation.setDuration(1);
        reverseRotateAnimation.setFillAfter(true);
    }
    private OnClickListener loadMoreClickListener = new OnClickListener() {
        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            if (!isLoadingMore) {
                isLoadingMore = true;
                footerProgressBar.setVisibility(View.VISIBLE);
                refreshDelegate.startLoadMore();
            }
        }
    };
    public void onRefreshComplete() {
        progressBar.setVisibility(View.GONE);
        arrowImage.setVisibility(View.VISIBLE);
        arrowImage.startAnimation(reverseRotateAnimation);
        headerRelativeLayout.setPadding(headerRelativeLayout.getPaddingLeft(),
                -1 * HEADER_HEIGHT, 0, headerRelativeLayout.getPaddingBottom());
        SimpleDateFormat format =new SimpleDateFormat("MMM dd, yyyy HH:mm:ss");
        String date=format.format(new Date());
        lastUpdateDateTextView.setText("Last Updated: " + date);
        isLoading = false;
        //isDragging = false;
    }
    public void onRefreshStart() {
        headerRelativeLayout.setPadding(headerRelativeLayout.getPaddingLeft(),
                HEADER_TOP, 0, headerRelativeLayout.getPaddingBottom());
        headerTextView.setText(R.string.loading);
        progressBar.setVisibility(View.VISIBLE);
        arrowImage.setVisibility(View.GONE);
        isLoading = true;
        if (refreshDelegate != null) {
            refreshDelegate.startFresh();
        }
    }
    public void setOnRefresh(RefreshableInterface d){
        refreshDelegate = d;
    }
    public void onLoadingMoreComplete() {
        footerProgressBar.setVisibility(View.GONE);
        isLoadingMore = false;
    }
}

布局

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >
    <ListView
        android:id="@+id/postListView"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" />

</RelativeLayout>

Answer 1

在您的布局上：

<ListView
        android:id="@+id/postListView"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" />

你不应该这样做吗？

<RefreshableListView 
        android:id="@+id/postListView"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" />

Answer 2

您使用的是一个普通的ListView，它不能强制转换为RefreshableListView。要修复更改您的布局如下：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<com.package.RefreshableListView
    android:id="@+id/postListView"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" />

</RelativeLayout>

您必须使用RefreshableListView 的包更改com.package.