2021.5.11 Android软件缓冲加载页面

一、今日学习内容

   参考文章：Android 自定义WebView 实现可以加载缓存数据 - Jason_Jan - 博客园 (cnblogs.com)

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() ;

    
}

import java.util.List;

import com.heima.googleplay.utils.UIUtils;
import com.heima.googleplay.utils.ViewUtils;
import com.heima.googleplay.widget.LoadingPage;
import com.heima.googleplay.widget.LoadingPage.LoadResult;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewParent;

public abstract class BaseFragment extends Fragment {

    private LoadingPage mContentPage;
    
    
    
    //setContentView
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        //当前的view已经有了一个父亲。必须移除
        if(mContentPage == null){
            mContentPage = new LoadingPage(UIUtils.getContext()) {

                @Override
                public View createSuccessView() {
                    // TODO Auto-generated method stub
                    return BaseFragment.this.createSuccessView();
                }

                @Override
                public LoadResult Load() {
                    // TODO Auto-generated method stub
                    return BaseFragment.this.load();
                }
            };
        }else{
            ViewUtils.removeSelfFromParent(mContentPage);
        }
        
        return mContentPage;
    }
    /**
     * 检查服务器返回的json数据
     * @param object
     * @return
     */
    protected LoadResult chece(Object object) {
        if (object == null) {
            return LoadResult.ERROR;
        }
        if (object instanceof List) {
            List list = (List) object;
            if (list.size() == 0) {
                return LoadResult.EMPTY;
            }
        }

        return LoadResult.SUCCESS;
    }

    protected abstract LoadResult load();

    protected abstract View createSuccessView();

    //在MainActivity中调用
    public void show() {
        if (null != mContentPage) {
            mContentPage.show();
        }

    }

}

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.app.FragmentStatePagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.view.Menu;

import com.heima.googleplay.fragment.AppFragment;
import com.heima.googleplay.fragment.BaseFragment;
import com.heima.googleplay.fragment.FragmentFactory;
import com.heima.googleplay.fragment.GameFragment;
import com.heima.googleplay.fragment.HomeFragment;
import com.heima.googleplay.utils.UIUtils;
import com.heima.googleplay.widget.PagerTab;

public class MainActivity extends BaseActivity implements OnPageChangeListener {


    private PagerTab mTabs;
    private ViewPager mPager;


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

     private class MainAdapter extends FragmentStatePagerAdapter{

        private String[] tab_names;
        private BaseFragment fragment;

        public MainAdapter(FragmentManager fm) {
            super(fm);
            tab_names = UIUtils.getStringArray(R.array.tab_names);
        }

        @Override
        public CharSequence getPageTitle(int position) {
            // TODO Auto-generated method stub
            return tab_names[position];
        }
        
        @Override
        public Fragment getItem(int position) {
            
            return FragmentFactory.createFragment(position);
        }

        @Override
        public int getCount() {
            // TODO Auto-generated method stub
            return tab_names.length;
        }
         
     }

    @Override
    protected void initView() {
        setContentView(R.layout.activity_main);
        mTabs = (PagerTab) findViewById(R.id.tabs);
        mPager = (ViewPager) findViewById(R.id.pager);
        MainAdapter adapter = new MainAdapter(getSupportFragmentManager());
        mPager.setAdapter(adapter);
        //绑定到一起
        mTabs.setViewPager(mPager);
        mTabs.setOnPageChangeListener(this);
    }

    @Override
    public void onPageScrollStateChanged(int arg0) {
        // TODO Auto-generated method stub
        
    }

    @Override
    public void onPageScrolled(int arg0, float arg1, int arg2) {
        // TODO Auto-generated method stub
        
    }

    @Override
    public void onPageSelected(int arg0) {
        BaseFragment fragment = FragmentFactory.createFragment(arg0);
        fragment.show();
    }

}

MainActivity