android 应用架构随笔六（Loading加载页面）

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import com.heima.googleplay.R;
import com.heima.googleplay.manager.ThreadManager;
import com.heima.googleplay.utils.UIUtils;

import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.widget.FrameLayout;
/**
 * 
 * 
 * ============================================================
 **/
public abstract class LoadingPage extends FrameLayout {
    //默认状态
    private final int UN_LOADING  =  1;
    //加载状态
    private final int LOADING = 2;
    //加载失败状态
    private final int ERROR = 3;
    //加载成功。然后服务器没有返回数据
    private final int EMPTY = 4;
    //加载成功的状态
    private final int SUCCESS = 5;
    //用来记录某种状态
    private int mState;
    private View mLoadingView;
    private View mErrorView;
    private View mEmptyView;

    private View mSuccessView;
    public LoadingPage(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init();
    }

    private void init() {
        //首先赋值
        mState = UN_LOADING;
        
        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));
        }
        //成功页面根据业务不同页面将不同，所以在此无法添加统一界面
　　　　　//只能在主线程中展示出来
        showSafePage();
        
    }

　　
    private void showSafePage() {
        UIUtils.runInMainThread(new Runnable() {
            
            @Override
            public void run() {
                showPage();
                
            }
        });
        
    }

　　//三种页面已经添加到FrameLayout中，通过显示和隐藏来控制显示那个
    protected void showPage() {
        if(null != mLoadingView){
            mLoadingView.setVisibility(mState == UN_LOADING || mState ==  LOADING ? View.VISIBLE : View.INVISIBLE);
        }
        
        if(null != mErrorView){
            mErrorView.setVisibility(mState == ERROR ? View.VISIBLE : View.INVISIBLE);
        }
        
        if(null != mEmptyView){
            mEmptyView.setVisibility(mState == EMPTY ? View.VISIBLE : View.INVISIBLE);
        }
        
        if(null == mSuccessView && mState == SUCCESS ){
            mSuccessView = createSuccessView();
            addView(mSuccessView, new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
        }
        if(null != mSuccessView){
            mSuccessView.setVisibility(mState == SUCCESS ? View.VISIBLE : View.INVISIBLE);
        }
    }

    public abstract View createSuccessView();//创建成功后显示的业务界面

    private View createEmptyView() {
        // TODO Auto-generated method stub
        return UIUtils.inflate(R.layout.loading_page_empty);
    }

    private View createErrorView() {
        // TODO Auto-generated method stub
        return UIUtils.inflate(R.layout.loading_page_error);
    }

    private View createLoadingView() {
        // TODO Auto-generated method stub
        return UIUtils.inflate(R.layout.loading_page_loading);
    }

    public LoadingPage(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public LoadingPage(Context context) {
        super(context);
        init();
    }
//    //加载失败状态
//        private final int ERROR = 3;
//        //加载成功。然后服务器没有返回数据
//        private final int EMPTY = 4;
//        //加载成功的状态
//        private final int SUCCESS = 5;
    public enum LoadResult{
        ERROR(3),EMPTY(4),SUCCESS(5);
        int value ;
        LoadResult(int value){
            this.value = value;
        }
        public int getValue() {
            return value;
        }
    }
    
　　//利用线程池
    private class LoadTask implements Runnable{

        @Override
        public void run() {
            final LoadResult result = Load();
            UIUtils.runInMainThread(new Runnable() {
                
                @Override
                public void run() {
                    
                    mState = result.getValue();
                    
                    showPage();
                }
            });
            
        }
        
    }

    public void show() {
        if(mState == ERROR || mState == EMPTY){
            mState = UN_LOADING;
        }
        
        if(mState == UN_LOADING){
            mState = LOADING;
            
            LoadTask task = new LoadTask();
            ThreadManager.getLongPool().execute(task);
//            ExecutorService service = Executors.newFixedThreadPool(3);
//            LoadTask task = new LoadTask();
//            service.execute(task);
        }
        showSafePage();//加载完数据，在主线程中展示界面出来

} 　　
　　
　　//从服务器加载数据，返回加载状态（加载数据成功、失败？）
    public abstract LoadResult Load() ;

    
}