XListView+HttpURLConnection+imageLoader-优快云博客

本文链接：https://blog.youkuaiyun.com/ChEngDieYl/article/details/78911644

本文详细介绍了如何结合XListView、HttpURLConnection和imageLoader来实现高效的数据加载与图片显示，涵盖了XListView的底部和头部组件用法。

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> XlistView

package weilin.bwei.com.weilin20171227.xlistviewtext;

import android.annotation.SuppressLint;
import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewTreeObserver;
import android.view.animation.DecelerateInterpolator;
import android.widget.AbsListView;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.RelativeLayout;
import android.widget.Scroller;
import android.widget.TextView;

import java.text.SimpleDateFormat;
import java.util.Date;

import weilin.bwei.com.weilin20171227.R;

/**
 * Created by lenovo on 2017/12/27.
 */

public class XListView extends ListView implements AbsListView.OnScrollListener {
    private float mLastY = -1; // save event y
    private Scroller mScroller; // 用于回滚
    private OnScrollListener mScrollListener; // 回滚监听
    // 触发刷新和加载更多接口.
    private IXListViewListener mListViewListener;
    // -- 头部的View
    private XListViewHeader mHeaderView;
    // 查看头部的内容，用它计算头部高度，和隐藏它
    // 当禁用的时候刷新
    private RelativeLayout mHeaderViewContent;
    private TextView mHeaderTimeView;
    private int mHeaderViewHeight; // 头部View的高
    private boolean mEnablePullRefresh = true;
    private boolean mPullRefreshing = false; // 是否刷新.
    // -- 底部的View
    private XListViewFooter mFooterView;
    private boolean mEnablePullLoad;
    private boolean mPullLoading;
    private boolean mIsFooterReady = false;
    // 总列表项，用于检测列表视图的底部
    private int mTotalItemCount;

    // for mScroller, 滚动页眉或者页脚
    private int mScrollBack;
    private final static int SCROLLBACK_HEADER = 0;// 顶部
    private final static int SCROLLBACK_FOOTER = 1;// 下部

    private final static int SCROLL_DURATION = 400; // 滚动回时间
    private final static int PULL_LOAD_MORE_DELTA = 50; // 当大于50PX的时候，加载更多

    private final static float OFFSET_RADIO = 1.8f; // support iOS like pull
    // feature.

    /**
     * @param context
     */
    public XListView(Context context) {
        super(context);
        initWithContext(context);
    }

    public XListView(Context context, AttributeSet attrs) {
        super(context, attrs);
        initWithContext(context);
    }

    public XListView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        initWithContext(context);
    }

    private void initWithContext(Context context) {
        mScroller = new Scroller(context, new DecelerateInterpolator());
        // XListView need the scroll event, and it will dispatch the event to
        // user's listener (as a proxy).
        super.setOnScrollListener(this);

        // 初始化头部View
        mHeaderView = new XListViewHeader(context);
        mHeaderViewContent = (RelativeLayout) mHeaderView
                .findViewById(R.id.xlistview_header_content);
        mHeaderTimeView = (TextView) mHeaderView
                .findViewById(R.id.xlistview_header_time);
        addHeaderView(mHeaderView);// 把头部这个视图添加进去

        // 初始化底部的View
        mFooterView = new XListViewFooter(context);

        // 初始化头部高度
        mHeaderView.getViewTreeObserver().addOnGlobalLayoutListener(
                new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                mHeaderViewHeight = mHeaderViewContent.getHeight();
                getViewTreeObserver()
                        .removeGlobalOnLayoutListener(this);
            }
        });


    }

    @Override
    public void setAdapter(ListAdapter adapter) {
        // 确定XListViewFooter是最后底部的View, 并且只有一次
        if (mIsFooterReady == false) {
            mIsFooterReady = true;
            addFooterView(mFooterView);
        }
        super.setAdapter(adapter);
    }

    /**
     * 启用或禁用下拉刷新功能.
     *
     * @param enable
     */
    public void setPullRefreshEnable(boolean enable) {
        mEnablePullRefresh = enable;
        if (!mEnablePullRefresh) { // 禁用,隐藏内容
            mHeaderViewContent.setVisibility(View.INVISIBLE);// 如果为false则隐藏下拉刷新功能
        } else {
            mHeaderViewContent.setVisibility(View.VISIBLE);// 否则就显示下拉刷新功能
        }
    }

    /**
     * 启用或禁用加载更多的功能.
     *
     * @param enable
     */
    public void setPullLoadEnable(boolean enable) {
        mEnablePullLoad = enable;
        if (!mEnablePullLoad) {
            mFooterView.hide();// 隐藏
            mFooterView.setOnClickListener(null);
        } else {
            mPullLoading = false;
            mFooterView.show();// 显示
            mFooterView.setState(XListViewFooter.STATE_NORMAL);
            // both "上拉" 和 "点击" 将调用加载更多.
            mFooterView.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View v) {
                    startLoadMore();
                }
            });
        }
    }

    /**
     * 停止刷新, 重置头视图.
     */
    public void stopRefresh() {
        if (mPullRefreshing == true) {
            mPullRefreshing = false;
            resetHeaderHeight();
        }
    }

    /**
     * stop load more, reset footer view.
     */
    public void stopLoadMore() {
        if (mPullLoading == true) {
            mPullLoading = false;
            mFooterView.setState(XListViewFooter.STATE_NORMAL);
        }
    }

    /**
     * 設置最後一次刷新時間
     *
     * @param time
     */
    @SuppressLint("SimpleDateFormat")
    public void setRefreshTime(String time) {
        SimpleDateFormat formatter   =   new   SimpleDateFormat   ("yyyy年MM月dd日   HH:mm:ss     ");
        Date curDate   =   new   Date(System.currentTimeMillis());
        //获取当前时间
        String   str   =   formatter.format(curDate);
        mHeaderTimeView.setText(str);
    }

    private void invokeOnScrolling() {
        if (mScrollListener instanceof OnXScrollListener) {
            OnXScrollListener l = (OnXScrollListener) mScrollListener;
            l.onXScrolling(this);
        }
    }

    private void updateHeaderHeight(float delta) {
        mHeaderView.setVisiableHeight((int) delta
                + mHeaderView.getVisiableHeight());
        if (mEnablePullRefresh && !mPullRefreshing) { // 未处于刷新状态，更新箭头
            if (mHeaderView.getVisiableHeight() > mHeaderViewHeight) {
                mHeaderView.setState(XListViewHeader.STATE_READY);
            } else {
                mHeaderView.setState(XListViewHeader.STATE_NORMAL);
            }
        }
        setSelection(0); // scroll to top each time
    }

    /**
     * 重置头视图的高度
     */
    private void resetHeaderHeight() {
        int height = mHeaderView.getVisiableHeight();
        if (height == 0) // 不显示.
            return;
        // 不显示刷新和标题的时候，什么都不显示
        if (mPullRefreshing && height <= mHeaderViewHeight) {
            return;
        }
        int finalHeight = 0; // 默认：滚动回头.
        // 当滚动回显示所有头标题时候，刷新
        if (mPullRefreshing && height > mHeaderViewHeight) {
            finalHeight = mHeaderViewHeight;
        }
        mScrollBack = SCROLLBACK_HEADER;
        mScroller.startScroll(0, height, 0, finalHeight - height,
                SCROLL_DURATION);
        // 触发刷新
        invalidate();
    }

    // 改变底部视图高度
    private void updateFooterHeight(float delta) {
        int height = mFooterView.getBottomMargin() + (int) delta;
        if (mEnablePullLoad && !mPullLoading) {
            if (height > PULL_LOAD_MORE_DELTA) { // 高度足以调用加载更多
                mFooterView.setState(XListViewFooter.STATE_READY);
            } else {
                mFooterView.setState(XListViewFooter.STATE_NORMAL);
            }
        }
        mFooterView.setBottomMargin(height);

        // setSelection(mTotalItemCount - 1); // scroll to bottom
    }

    private void resetFooterHeight() {
        int bottomMargin = mFooterView.getBottomMargin();
        if (bottomMargin > 0) {
            mScrollBack = SCROLLBACK_FOOTER;
            mScroller.startScroll(0, bottomMargin, 0, -bottomMargin,
                    SCROLL_DURATION);
            invalidate();
        }
    }

    // 开始加载更多
    private void startLoadMore() {
        mPullLoading = true;
        mFooterView.setState(XListViewFooter.STATE_LOADING);
        if (mListViewListener != null) {
            mListViewListener.onLoadMore();
        }
    }

    // 触发事件
    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        if (mLastY == -1) {
            mLastY = ev.getRawY();
        }

        switch (ev.getAction()) {
            case MotionEvent.ACTION_DOWN:
                mLastY = ev.getRawY();
                break;
            case MotionEvent.ACTION_MOVE:
                final float deltaY = ev.getRawY() - mLastY;
                mLastY = ev.getRawY();
                System.out.println("数据监测：" + getFirstVisiblePosition() + "---->"
                        + getLastVisiblePosition());
                if (getFirstVisiblePosition() == 0
                        && (mHeaderView.getVisiableHeight() > 0 || deltaY > 0)) {
                    // 第一项显示,标题显示或拉下来.
                    updateHeaderHeight(deltaY / OFFSET_RADIO);
                    invokeOnScrolling();
                } else if (getLastVisiblePosition() == mTotalItemCount - 1
                        && (mFooterView.getBottomMargin() > 0 || deltaY < 0)) {
                    // 最后一页，已停止或者想拉起
                    updateFooterHeight(-deltaY / OFFSET_RADIO);
                }
                break;
            default:
                mLastY = -1; // 重置
                if (getFirstVisiblePosition() == 0) {
                    // 调用刷新,如果头部视图高度大于设定高度。
                    if (mEnablePullRefresh
                            && mHeaderView.getVisiableHeight() > mHeaderViewHeight) {
                        mPullRefreshing = true;// 那么刷新
                        mHeaderView.setState(XListViewHeader.STATE_REFRESHING);
                        if (mListViewListener != null) {
                            mListViewListener.onRefresh();
                        }
                    }
                    resetHeaderHeight();// 刷新完毕，重置头部高度，也就是返回上不
                }
                if (getLastVisiblePosition() == mTotalItemCount - 1) {
                    // 调用加载更多.
                    if (mEnablePullLoad
                            && mFooterView.getBottomMargin() > PULL_LOAD_MORE_DELTA) {
                        startLoadMore();// 如果底部视图高度大于可以加载高度，那么就开始加载
                    }
                    resetFooterHeight();// 重置加载更多视图高度
                }
                break;
        }
        return super.onTouchEvent(ev);
    }

    @Override
    public void computeScroll() {
        if (mScroller.computeScrollOffset()) {
            if (mScrollBack == SCROLLBACK_HEADER) {
                mHeaderView.setVisiableHeight(mScroller.getCurrY());
            } else {
                mFooterView.setBottomMargin(mScroller.getCurrY());
            }
            postInvalidate();
            invokeOnScrolling();
        }
        super.computeScroll();
    }

    @Override
    public void setOnScrollListener(OnScrollListener l) {
        mScrollListener = l;
    }

    @Override
    public void onScrollStateChanged(AbsListView view, int scrollState) {
        if (mScrollListener != null) {
            mScrollListener.onScrollStateChanged(view, scrollState);
        }
    }

    @Override
    public void onScroll(AbsListView view, int firstVisibleItem,
                         int visibleItemCount, int totalItemCount) {
        // 发送到用户的监听器
        mTotalItemCount = totalItemCount;
        if (mScrollListener != null) {
            mScrollListener.onScroll(view, firstVisibleItem, visibleItemCount,
                    totalItemCount);
        }
    }

    public void setXListViewListener(IXListViewListener l) {
        mListViewListener = l;
    }

    /**
     * 你可以监听到列表视图，OnScrollListener 或者这个. 他将会被调用 , 当头部或底部触发的时候
     */
    public interface OnXScrollListener extends OnScrollListener {
        public void onXScrolling(View view);
    }

    /**
     * 实现这个接口来刷新/负载更多的事件
     */
    public interface IXListViewListener {
        public void onRefresh();

        public void onLoadMore();
    }
}

XListViewFooter

package weilin.bwei.com.weilin20171227.xlistviewtext;

import android.content.Context;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.TextView;

import weilin.bwei.com.weilin20171227.R;

public class XListViewFooter extends LinearLayout {
	public final static int STATE_NORMAL = 0;
	public final static int STATE_READY = 1;
	public final static int STATE_LOADING = 2;

	private Context mContext;

	private View mContentView;
	private View mProgressBar;
	private TextView mHintView;

	public XListViewFooter(Context context) {
		super(context);
		initView(context);
	}

	public XListViewFooter(Context context, AttributeSet attrs) {
		super(context, attrs);
		initView(context);
	}

	public void setState(int state) {
		mHintView.setVisibility(View.INVISIBLE);// 开始底部控件都隐藏
		mProgressBar.setVisibility(View.INVISIBLE);
		mHintView.setVisibility(View.INVISIBLE);
		if (state == STATE_READY) {// 如果是第一页状态，那么“查看更多”显示
			mHintView.setVisibility(View.VISIBLE);
			mHintView.setText(R.string.xlistview_footer_hint_ready);// 松开显示更多
		} else if (state == STATE_LOADING) {// 当加载的时候
			mProgressBar.setVisibility(View.VISIBLE);// 加载进度条显示
		} else {
			mHintView.setVisibility(View.VISIBLE);
			mHintView.setText(R.string.xlistview_footer_hint_normal);// 查看更多
		}
	}

	public void setBottomMargin(int height) {
		if (height < 0)
			return;
		LayoutParams lp = (LayoutParams) mContentView
				.getLayoutParams();
		lp.bottomMargin = height;
		mContentView.setLayoutParams(lp);
	}

	public int getBottomMargin() {
		LayoutParams lp = (LayoutParams) mContentView
				.getLayoutParams();
		return lp.bottomMargin;
	}

	/**
	 * normal status
	 */
	public void normal() {
		mHintView.setVisibility(View.VISIBLE);
		mProgressBar.setVisibility(View.GONE);
	}

	/**
	 * loading status
	 */
	public void loading() {
		mHintView.setVisibility(View.GONE);
		mProgressBar.setVisibility(View.VISIBLE);
	}

	/**
	 * 当禁用拉加载更多隐藏底部视图
	 */
	public void hide() {
		LayoutParams lp = (LayoutParams) mContentView
				.getLayoutParams();
		lp.height = 0;
		mContentView.setLayoutParams(lp);
	}

	/**
	 * 显示底部视图
	 */
	public void show() {
		LayoutParams lp = (LayoutParams) mContentView
				.getLayoutParams();
		lp.height = LayoutParams.WRAP_CONTENT;
		mContentView.setLayoutParams(lp);
	}

	private void initView(Context context) {
		mContext = context;
		LinearLayout moreView = (LinearLayout) LayoutInflater.from(mContext)
				.inflate(R.layout.xlistview_footer, null);
		addView(moreView);
		moreView.setLayoutParams(new LayoutParams(
				LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT));

		mContentView = moreView.findViewById(R.id.xlistview_footer_content);
		mProgressBar = moreView.findViewById(R.id.xlistview_footer_progressbar);
		mHintView = (TextView) moreView
				.findViewById(R.id.xlistview_footer_hint_textview);
	}

}

> XListViewHeader

package weilin.bwei.com.weilin20171227.xlistviewtext;

import android.content.Context;
import android.util.AttributeSet;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.RotateAnimation;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ProgressBar;
import android.widget.TextView;

import weilin.bwei.com.weilin20171227.R;

public class XListViewHeader extends LinearLayout {
	private LinearLayout mContainer;
	private ImageView mArrowImageView;
	private ProgressBar mProgressBar;
	private TextView mHintTextView;
	private int mState = STATE_NORMAL;// 初始状态

	private Animation mRotateUpAnim;
	private Animation mRotateDownAnim;

	private final int ROTATE_ANIM_DURATION = 180;

	public final static int STATE_NORMAL = 0;
	public final static int STATE_READY = 1;
	public final static int STATE_REFRESHING = 2;

	public XListViewHeader(Context context) {
		super(context);
		initView(context);
	}

	/**
	 * @param context
	 * @param attrs
	 */
	public XListViewHeader(Context context, AttributeSet attrs) {
		super(context, attrs);
		initView(context);
	}

	private void initView(Context context) {
		// 初始情况，设置下拉刷新view高度为0
		LayoutParams lp = new LayoutParams(
				LayoutParams.FILL_PARENT, 0);
		// 时间TextView
		mContainer = (LinearLayout) LayoutInflater.from(context).inflate(
				R.layout.xlistview_header, null);
		addView(mContainer, lp);
		setGravity(Gravity.BOTTOM);
		// 找到头部页面里的控件
		mArrowImageView = (ImageView) findViewById(R.id.xlistview_header_arrow);
		mHintTextView = (TextView) findViewById(R.id.xlistview_header_hint_textview);
		mProgressBar = (ProgressBar) findViewById(R.id.xlistview_header_progressbar);

		mRotateUpAnim = new RotateAnimation(0.0f, -180.0f,
				Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF,
				0.5f);
		mRotateUpAnim.setDuration(ROTATE_ANIM_DURATION);
		mRotateUpAnim.setFillAfter(true);
		mRotateDownAnim = new RotateAnimation(-180.0f, 0.0f,
				Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF,
				0.5f);
		mRotateDownAnim.setDuration(ROTATE_ANIM_DURATION);
		mRotateDownAnim.setFillAfter(true);
	}

	// 设置状态
	public void setState(int state) {
		if (state == mState)
			return;

		if (state == STATE_REFRESHING) { // 显示进度
			mArrowImageView.clearAnimation();
			mArrowImageView.setVisibility(View.INVISIBLE);// 不显示图片
			mProgressBar.setVisibility(View.VISIBLE);// 显示进度条
		} else { // 显示箭头图片
			mArrowImageView.setVisibility(View.VISIBLE);
			mProgressBar.setVisibility(View.INVISIBLE);
		}

		switch (state) {
			case STATE_NORMAL:
				if (mState == STATE_READY) {// 当状态时准备的时候，显示动画
					mArrowImageView.startAnimation(mRotateDownAnim);
				}
				if (mState == STATE_REFRESHING) {// 当状态显示进度条的时候，清除动画
					mArrowImageView.clearAnimation();
				}
				mHintTextView.setText(R.string.xlistview_header_hint_normal);// 文字提示：下拉刷新
				break;
			case STATE_READY:
				if (mState != STATE_READY) {
					mArrowImageView.clearAnimation();
					mArrowImageView.startAnimation(mRotateUpAnim);
					mHintTextView.setText(R.string.xlistview_header_hint_ready);// 松开刷新数据
				}
				break;
			case STATE_REFRESHING:
				mHintTextView.setText(R.string.xlistview_header_hint_loading);
				break;
			default:
		}

		mState = state;
	}

	public void setVisiableHeight(int height) {
		if (height < 0)
			height = 0;
		LayoutParams lp = (LayoutParams) mContainer
				.getLayoutParams();
		lp.height = height;
		mContainer.setLayoutParams(lp);
	}

	public int getVisiableHeight() {
		return mContainer.getHeight();
	}

}

xlistview_footer

<?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="match_parent">
    <RelativeLayout
        android:id="@+id/xlistview_footer_content"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:padding="10dp" >

        <ProgressBar
            android:id="@+id/xlistview_footer_progressbar"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:visibility="invisible" />

        <TextView
            android:id="@+id/xlistview_footer_hint_textview"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:text="@string/xlistview_footer_hint_normal" />
    </RelativeLayout>
</LinearLayout>

> xlistview_header

<?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="match_parent">
    <RelativeLayout
        android:id="@+id/xlistview_header_content"
        android:layout_width="fill_parent"
        android:layout_height="60dp" >

        <LinearLayout
            android:id="@+id/xlistview_header_text"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:gravity="center"
            android:orientation="vertical" >

            <TextView
                android:id="@+id/xlistview_header_hint_textview"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/xlistview_header_hint_normal" />

            <LinearLayout
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginTop="3dp" >

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="@string/xlistview_header_last_time"
                    android:textSize="12sp" />

                <TextView
                    android:id="@+id/xlistview_header_time"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:textSize="12sp" />
            </LinearLayout>
        </LinearLayout>

        <ImageView
            android:id="@+id/xlistview_header_arrow"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignLeft="@id/xlistview_header_text"
            android:layout_centerVertical="true"
            android:layout_marginLeft="-35dp"
            android:src="@mipmap/xlistview_arrow" />

        <ProgressBar
            android:id="@+id/xlistview_header_progressbar"
            android:layout_width="30dp"
            android:layout_height="30dp"
            android:layout_alignLeft="@id/xlistview_header_text"
            android:layout_centerVertical="true"
            android:layout_marginLeft="-40dp"
            android:visibility="invisible" />
    </RelativeLayout>
</LinearLayout>