LoadingPage.java

package com.bczm.widgetcollections.ui.widget;
import android.content.Context;
import android.view.View;
import android.widget.FrameLayout;
import android.widget.TextView;

import com.bczm.widgetcollections.R;
import com.bczm.widgetcollections.ThreadManager;
import com.bczm.widgetcollections.utils.UIUtils;

/**
 * @author：Jorge on 2015/9/2 11:39
 */
public abstract class LoadingPage extends FrameLayout {
    private static final int STATE_UNLOADED = 0;//未知状态
    private static final int STATE_LOADING = 1;//加载状态
    private static final int STATE_ERROR = 3;//加载完毕，但是出错状态
    private static final int STATE_EMPTY = 4;//加载完毕，但是没有数据状态
    private static final int STATE_SUCCEED = 5;//加载成功

    private View mLoadingView;//加载时显示的View
    private View mErrorView;//加载出错显示的View
    private View mEmptyView;//加载没有数据显示的View
    private View mSucceedView;//加载成功显示的View

    private int mState;//当前的状态，显示需要根据该状态判断

    public LoadingPage(Context context) {
        super(context);
        init();
    }

    private void init() {
        setBackgroundColor(UIUtils.getColor(R.color.bg_page));//设置背景
        mState = STATE_UNLOADED;//初始化状态

        //创建对应的View，并添加到布局中
        mLoadingView = createLoadingView();
        if (null != mLoadingView) {
            addView(mLoadingView, new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
        }

        mErrorView = createErrorView();
        if (null != mErrorView) {
            addView(mErrorView, new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
        }

        mEmptyView = createEmptyView();
        if (null != mEmptyView) {
            addView(mEmptyView, new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
        }
        //显示对应的View
        showPageSafe();
    }

    /** 线程安全的方法 */
    private void showPageSafe() {
        UIUtils.runInMainThread(new Runnable() {
            @Override
            public void run() {
                showPage();
            }
        });
    }

    /** 显示对应的View */
    private void showPage() {
        if (null != mLoadingView) {
            mLoadingView.setVisibility(mState == STATE_UNLOADED || mState == STATE_LOADING ? View.VISIBLE : View.INVISIBLE);
        }
        if (null != mErrorView) {
            mErrorView.setVisibility(mState == STATE_ERROR ? View.VISIBLE : View.INVISIBLE);
        }
        if (null != mEmptyView) {
            mEmptyView.setVisibility(mState == STATE_EMPTY ? View.VISIBLE : View.INVISIBLE);
        }

        // 只有数据成功返回了，才知道成功的View该如何显示，因为该View的显示依赖加载完毕的数据
        if (mState == STATE_SUCCEED && mSucceedView == null) {
            mSucceedView = createLoadedView();
            addView(mSucceedView, new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
        }

        if (null != mSucceedView) {
            mSucceedView.setVisibility(mState == STATE_SUCCEED ? View.VISIBLE : View.INVISIBLE);
        }
    }

    /** 恢复状态 */
    public void reset() {
        mState = STATE_UNLOADED;
        showPageSafe();
    }

    /** 是否需要恢复状态 */
    protected boolean needReset() {
        return mState == STATE_ERROR || mState == STATE_EMPTY;
    }

    /** 有外部调用，会根据状态判断是否引发load */
    public synchronized void show() {
        if (needReset()) {
            mState = STATE_UNLOADED;
        }
        if (mState == STATE_UNLOADED) {
            mState = STATE_LOADING;
            LoadingTask task = new LoadingTask();
            ThreadManager.getLongPool().execute(task);
        }else{
        showPageSafe();
        }
    }

    protected View createLoadingView() {
        String[] names= UIUtils.getStringArray(R.array.marks);
        int  num= (int) (Math.random()*names.length);
        View view=  UIUtils.inflate(R.layout.loading_page_loading);
        TextView tv= (TextView) view.findViewById(R.id.tv_mark);
        tv.setText(names[num]);
        return view;


    }

    protected View createEmptyView() {
        return UIUtils.inflate(R.layout.loading_page_empty);
    }

    protected View createErrorView() {
        View view = UIUtils.inflate(R.layout.loading_page_error);
        view.findViewById(R.id.page_bt).setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                show();
            }
        });
        return view;
    }

    public abstract View createLoadedView();

    public abstract LoadResult load();

    class LoadingTask implements Runnable {
        @Override
        public void run() {
            final LoadResult loadResult = load();
            UIUtils.runInMainThread(new Runnable() {//主线程改变UI
                @Override
                public void run() {
                    //状态的改变和界面息息相关，所以需要放到主线程来赋值，保障同步性
                    mState = loadResult.getValue();//根据枚举对象的返回值来改变显示状态码
                    showPage();
                }
            });
        }
    }

    public enum LoadResult {
        ERROR(3), EMPTY(4), SUCCEED(5);
        int value;

        LoadResult(int value) {
            this.value = value;
        }

        public int getValue() {
            return value;
        }
    }
}