android - 在 TabLayout 中使用多个 webview 来处理内存问题的逻辑

Question

我在 Tablayout 中有将近 30 个 webview。一切正常，但我的应用程序消耗了大量内存，并且会因为内存问题而关闭。这是我在日志中得到的

04-05 21:00:09.458 19720-19801/com.example.choman.webview A/chromium: [FATAL:memory.cc(19)] Out of memory. size=16777216

这是我的 java 文件。基本上所有剩余的 29 个 fragment 都包含相同的代码，只是 url 发生了变化。我不确定如何处理。

public class stackOverflow extends Fragment {


    private WebView webView;
    private ProgressBar progressBar1;
    private SwipeRefreshLayout mSwipeRefreshLayout1;




    public stackOverflow() {
        // Required empty public constructor
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment


        return inflater.inflate(R.layout.fragment_tab1, container, false);


    }



    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {


        progressBar1 = (ProgressBar) view.findViewById(R.id.progressBar1);

        webView = (WebView) view.findViewById(R.id.website_detail_1);

        webView.setWebViewClient(new MyAppWebViewClient());
        webView.getSettings().setJavaScriptEnabled(true);
        webView.getSettings().setDomStorageEnabled(true);

        webView.loadUrl("http://www.stackoverflow.com");


        WebSettings webSettings = webView.getSettings();

        webView.getSettings().setCacheMode(WebSettings.LOAD_CACHE_ELSE_NETWORK);
        webView.getSettings().setAppCacheEnabled(true);
        webSettings.setDomStorageEnabled(true);

        webSettings.setLayoutAlgorithm(WebSettings.LayoutAlgorithm.SINGLE_COLUMN);


        mSwipeRefreshLayout1 = (SwipeRefreshLayout) view.findViewById(R.id.swipe1);
        mSwipeRefreshLayout1.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
            @Override
            public void onRefresh() {
                webView.loadUrl("http://www.stackoverflow.com");
            }
        });

        if (mSwipeRefreshLayout1.isRefreshing()) {
            mSwipeRefreshLayout1.setRefreshing(false);
        }


        webView.setOnKeyListener(new View.OnKeyListener() {
            @Override
            public boolean onKey(View v, int keyCode, KeyEvent event) {
                if ((keyCode == KeyEvent.KEYCODE_BACK) && webView.canGoBack()) {
                    webView.goBack();
                    return true;
                }

                return false;
            }
        });

    }

    public class MyAppWebViewClient extends WebViewClient {

        @Override
        public void onPageFinished(WebView view, String url) {
            super.onPageFinished(view, url);
            //view.findViewById(R.id.progressBar1).setVisibility(View.GONE);
            Log.i("pageFinished", "yesss");
            //progressBar.setVisibility(View.INVISIBLE);
            progressBar1.setVisibility(View.GONE);


            if (mSwipeRefreshLayout1.isRefreshing()) {
                mSwipeRefreshLayout1.setRefreshing(false);
            }


        }

        @Override
        public void onPageStarted(WebView view, String url, Bitmap favicon) {
            super.onPageStarted(view, url, favicon);
        }


        @Override
        public boolean shouldOverrideUrlLoading(WebView view, String url) {
            view.loadUrl(url);
            return true;
        }


    }
}

主要 Activity

public class MainActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {
    public WebView view;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);


        TabLayout tabLayout = (TabLayout) findViewById(R.id.tab_layout);


        tabLayout.addTab(tabLayout.newTab().setText("WebView1").setTag("WebView1"));
//all the way down to .....
tabLayout.addTab(tabLayout.newTab().setText("WebView30").setTag("WebView30"));        

        final ViewPager viewPager = (ViewPager) findViewById(R.id.pager);
        viewPager.setOffscreenPageLimit(6);


        final PagerAdapter adapter = new TabPagerAdapter(getSupportFragmentManager(), tabLayout
                .getTabCount());
        viewPager.setAdapter(adapter);

        viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(
                tabLayout));
        tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
            @Override
            public void onTabSelected(TabLayout.Tab tab) {
                viewPager.setCurrentItem(tab.getPosition());
            }

            @Override
            public void onTabUnselected(TabLayout.Tab tab) {

            }

            @Override
            public void onTabReselected(TabLayout.Tab tab) {

            }
        });


        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.setDrawerListener(toggle);
        toggle.syncState();

        NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this);

    }

    @Override
    public void onBackPressed() {
        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        if (drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }
    }

    @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;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        //    int id = item.getItemId();

//        //noinspection SimplifiableIfStatement
//        if (id == R.id.action_settings) {
//            return true;
//        }

        return super.onOptionsItemSelected(item);
    }

    @SuppressWarnings("StatementWithEmptyBody")
    @Override
    public boolean onNavigationItemSelected(MenuItem item) {

        ViewPager viewPager = (ViewPager) findViewById(R.id.pager);

        // Handle navigation view item clicks here.
        int id = item.getItemId();

        if (id == R.id.WebView1) {

            viewPager.setCurrentItem(0);

//all the way down to..30

 if (id == R.id.WebView30) {

            viewPager.setCurrentItem(30);






        }

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        drawer.closeDrawer(GravityCompat.START);
        return true;
    }
}

这是 TabPagerAdapter 的代码

public class TabPagerAdapter extends FragmentStatePagerAdapter
{

    int tabCount;


    public TabPagerAdapter(FragmentManager fm, int numberOfTabs)
    {
        super(fm);
        this.tabCount = numberOfTabs;

    }


    @Override
    public Fragment getItem(int position)
    {
        switch (position)
        {
            case 0:
//
                WebViewFragment1 tab1 = new WebViewFragment1();
                return tab1;

   //all the way to tab 29

    webViewFragment30 tab30 = new WebViewFragment30();
return tab30



            default:
                return null;

        }

    }

    @Override
    public int getCount()
    {
        return tabCount;
    }
}

Answer 1

使用ViewPager。 ViewPager 将随时在内存中保存最多 3 个 fragment (不更改默认的离屏页面限制)。 3个 fragment 是当前可见 fragment ，当前 fragment 的左侧和右侧 fragment 。

如果你想要标签，你可以创建一个看起来像系统标签的自定义 View ，并将它添加到 ViewPager 之上。将 PageTransformer 与 ViewPager 结合使用以跟踪 ViewPager 滑动并相应地滚动自定义选项卡。然后听 Tabs 的点击，并根据按下的 Tab 滚动 ViewPager。

更新:

我完全忘记了我们可以将 TabLayout 附加到 ViewPager 而不是创建自定义选项卡。

tabLayout.setUpWithViewPager(viewpager) 将起作用。

感谢@choman