ViewPager与包含TableLayouts加载缓慢片段： [英] ViewPager with Fragments that contain TableLayouts loads slowly:

问题描述

我正在开发一个 ViewPager 包含片段（最多每次4段），每个包含在 TableLayout 。所以基本上4表被载入。这是code加载数据到片段这就是后来附着在 ViewPager ：

I'm developing an Activity with a ViewPager that contains Fragments (Max 4 fragment each time) when each containing TableLayout. So basically 4 Tables are loaded. This is the code for loading the data into the Fragment which is later attached to the ViewPager:

 public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) 
{
    if (container == null) {
        return null;
    }

    LinearLayout.LayoutParams layoutParams=new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
    layoutParams.gravity=Gravity.CENTER_VERTICAL;
    layoutParams.setMargins(10, 0, 0, 0);

    fragmetLayout = (LinearLayout)inflater.inflate(R.layout.grid_fragment_layout, container, false);
    table = (TableLayout) fragmetLayout.findViewById(R.id.tlGridTable);
    llParameterContainer =  (LinearLayout) fragmetLayout.findViewById(R.id.llParametersContainer);
    tabName = (TextView) fragmetLayout.findViewById(R.id.tvTabName);
    tabName.setText(tab.getTabName());
    //tabName.setLayoutParams(layoutParams);

    for (Parameter parameter : SGRaportManagerAppObj.getInstance().parametersRepository.getParametersRepository())
    {
        ImageView parameterPoint = new ImageView(getActivity());
        parameterPoint.setImageResource(R.drawable.parameter_chosen_point);
        parameterPoint.setPadding(10, 10, 10, 0);
        parameterPoint.setLayoutParams(layoutParams);
        llParameterContainer.addView(parameterPoint);

        TextView parameterTextView = new TextView(getActivity());
        parameterTextView.setText(parameter.getName()+":");
        parameterTextView.setGravity(Gravity.CENTER);
        parameterTextView.setTextColor(getResources().getColor(R.color.my_black));  
        parameterTextView.setPadding(5, 10, 3, 10);
        parameterTextView.setLayoutParams(layoutParams);
        llParameterContainer.addView(parameterTextView);
        TextView parameterChosenValueTextView = new TextView(getActivity());
        parameterChosenValueTextView.setText(parameter.getChosenValue());
        parameterChosenValueTextView.setGravity(Gravity.CENTER); 
        parameterChosenValueTextView.setPadding(0, 10, 0, 10);
        parameterChosenValueTextView.setLayoutParams(layoutParams);
        parameterChosenValueTextView.setTextColor(getResources().getColor(R.color.my_black));   
        llParameterContainer.addView(parameterChosenValueTextView);

    }
    //table.setStretchAllColumns(true);  
    //table.setShrinkAllColumns(true); 
    TableRow tableRow = new TableRow(getActivity());
    TableLayout.LayoutParams tableRowParams=new TableLayout.LayoutParams(TableLayout.LayoutParams.WRAP_CONTENT,TableLayout.LayoutParams.WRAP_CONTENT);
    tableRowParams.setMargins(2, 0, 0, 0);
    tableRow.setLayoutParams(tableRowParams);
    Log.d(TAG, "TAB FROM FRAGMENT:"+tab.toString());


    TableRow.LayoutParams tlparamsFirstColumn = new TableRow.LayoutParams(TableRow.LayoutParams.WRAP_CONTENT, TableRow.LayoutParams.WRAP_CONTENT); 
    tlparamsFirstColumn.setMargins(4, 0, 2, 0);
    TableRow.LayoutParams tlparams = new TableRow.LayoutParams(TableRow.LayoutParams.WRAP_CONTENT, TableRow.LayoutParams.WRAP_CONTENT); 
    tlparams.setMargins(0, 0, 2, 0);

    //The First row for the column names.
    for (int i= 0; i < tab.getGrid().getGridColumnsList().size(); i++)
    {
        TextView tvName = new TextView(getActivity());
        String columnName = tab.getGrid().getGridColumnsList().get(i).getGridColumnAlias();
        tvName.setText(columnName);
        Log.d(TAG, "COLUMN ALIAS FROM FRAGMENT: "+columnName);
        if (i == 0)
        {
            tvName.setLayoutParams(tlparamsFirstColumn);
        }
        else
        {
            tvName.setLayoutParams(tlparams);
        }
        tvName.setGravity(Gravity.CENTER);
        tvName.setTextColor(getResources().getColor(R.color.my_white));  
        tvName.setPadding(10, 10, 10, 10);
        tvName.setBackgroundDrawable(getResources().getDrawable(R.drawable.grid_column_name_background));   
        tableRow.addView(tvName);
    }
    table.addView(tableRow);

    for (int j = 0; j < tab.getGrid().getGridData().getNumRows(); j++)
    {
        TableRow newRow = new TableRow(getActivity());
        TableLayout.LayoutParams insideRowParams=new TableLayout.LayoutParams(TableLayout.LayoutParams.WRAP_CONTENT,TableLayout.LayoutParams.WRAP_CONTENT);
        tableRowParams.setMargins(0, 2, 0, 0);
        for (int k = 0; k < tab.getGrid().getGridData().getNumCols(j); k++)
        {
            TextView tvName = new TextView(getActivity());
            String columnName = tab.getGrid().getGridData().get(j, k);
            tvName.setText(columnName);

            if ( (j % 2) == 0)
            {
                tvName.setBackgroundDrawable(getResources().getDrawable(R.drawable.grid_first_row_background)); 
            }
            else
            {
                tvName.setBackgroundDrawable(getResources().getDrawable(R.drawable.grid_second_row_background));    
            }
            if (k == 0)
            {
                tvName.setLayoutParams(tlparamsFirstColumn);
            }
            else
            {
                tvName.setLayoutParams(tlparams);
            }
            tvName.setGravity(Gravity.CENTER);
            tvName.setTextColor(getResources().getColor(R.color.my_black));  
            tvName.setPadding(10, 10, 10, 10);
            newRow.addView(tvName);  
        }
        table.addView(newRow);          
    }
    return fragmetLayout;
}

更新：

我ViewPagerActivity布局：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >

<TabHost
    android:id="@android:id/tabhost"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:layout_below="@+id/imageView3" >

    <LinearLayout
        android:orientation="vertical"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" >
        <FrameLayout
            android:id="@android:id/tabcontent"
            android:layout_width="0dp"
            android:layout_height="0dp"
            android:layout_weight="0"/>

        <android.support.v4.view.ViewPager
            android:id="@+id/pager"
            android:layout_width="fill_parent"
            android:layout_height="0dp"
            android:layout_weight="1" >
        </android.support.v4.view.ViewPager>

         <TabWidget
            android:id="@android:id/tabs"
            android:orientation="horizontal"
            android:layout_gravity="center_horizontal"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />
    </LinearLayout>
</TabHost>

 <ImageView
    android:id="@+id/imageView3"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginTop="-3dp"
    android:background="@drawable/login_scr_top_bar"
    android:contentDescription="@drawable/login_scr_top_bar" />

<TextView
    android:id="@+id/tvReportName"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="top|left"
    android:paddingLeft="15dp"
    android:paddingTop="13dp"
    android:text="@string/report_tabs"
    android:textColor="@color/my_black"
    android:textSize="18sp"
    android:textStyle="bold" />

<LinearLayout
    android:id="@+id/llTabsButtonsContainer"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_alignParentLeft="true"
    android:layout_alignParentRight="true"
    android:gravity="center_horizontal"
    android:orientation="horizontal"
    android:paddingBottom="5dp"
    android:paddingTop="5dp" > 
</LinearLayout>

<TextView
    android:id="@+id/tvReportTitle"
    android:layout_width="wrap_content"
    android:layout_height="20dp"
    android:layout_alignBaseline="@+id/tvReportName"
    android:layout_alignBottom="@+id/tvReportName"
    android:layout_toLeftOf="@+id/bBackToParameters"
    android:layout_toRightOf="@+id/tvReportName"
    android:text="TextView"
    android:textSize="18sp" />

<Button
    android:id="@+id/bBackToParameters"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignBottom="@+id/tvReportTitle"
    android:layout_marginRight="10dp"
    android:layout_alignParentRight="true"
    android:background="@drawable/button_back_to_parameters_selector"
    android:clickable="true"
    android:onClick="backToParametersButtonOnClick"
    android:padding="3dp"
    android:text="@string/back_to_parameters"
    android:textColor="@color/my_white"
    android:textStyle="bold" />

</RelativeLayout>

和我的GridFramgnet布局：

<?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"
android:orientation="vertical" >

<LinearLayout
android:id="@+id/llParametersContainer"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >
</LinearLayout>

<TextView 
    android:id="@+id/tvTabName"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" 
    android:textColor="@color/my_black"
    android:textStyle="bold"
    android:textSize="18sp"
    android:layout_marginLeft="10dp"
    android:text="It a test string for report Name"/>

    <ScrollView 
    android:id="@+id/layout" 
    android:layout_height="match_parent"         
    android:scrollbars="horizontal|vertical" 
    android:layout_width="match_parent"     
    android:layout_marginTop="5dip"     
    android:scrollbarStyle="outsideInset"
    android:fillViewport="true"> 

    <HorizontalScrollView 
        android:id="@+id/horizontalView" 
        android:layout_height="wrap_content"     
        android:scrollbars="horizontal|vertical" 
        android:layout_width="wrap_content"     
        android:layout_marginTop="5dip">

        <TableLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:id="@+id/tlGridTable" >   
        </TableLayout>
    </HorizontalScrollView>
   </ScrollView>
 </LinearLayout>

问题这3 片段大约需要10秒加载，这样用户在<$得到一个黑色的屏幕10秒C $ C>活动其实是加载。我怎么能避免呢？填充在表中运行的所有进程中的一个的AsyncTask 将我的 ViewPager 活动加载速度更快？可它甚至不能做到？

The Problem This for 3 Fragments takes about 10 seconds to load, so the user get a black screen for 10 second before the Activity is actually loaded. how can I avoid it? Running all the process of populating the tables in an AsyncTask will make my ViewPager Activity to load faster? can it even be done?

更新： 在大多数情况下是beeing花费填充/创建 TableLayout 。如果数据从那么它需要创建的TextView S的巨大数量和设置他们在 TableLayout 。

UPDATE: Most of the time is beeing spend to populate/create the TableLayout. If there is a big amount of data recieved from the server then it's needed to create a big amount of TextViews and set them in the TableLayout.

更新＃2： 嗯，我在消除了问题，因为据我了解我的需要（全景的水平和垂直滚动），我必须用 TableLayout ，所以我需要等待这段时间它需要加载它。但我需要找到一种方法来加载在片段中的数据至少与用户知道数据被填充（显示相应的对话框）。我试图把一个对话框中的的onCreate 的 ViewPager 开始之前，我的片段，但由于某些原因，初始化它不显示，我只看到了黑屏，直到装入片段。

UPDATE #2: Well I'm over eliminating the problem because as I understand for my needs (horizontal and vertical scrolling of whole view) I have to use TableLayout, So I need to wait this time it takes to load it. But I need to find a way to load the data in the fragments at least with the user knowing that the data is being populated (displaying appropriate Dialog). I tried to put a dialog in the onCreate of the ViewPager before I start the initialization of the fragment but for some reason it not showing and I only see the black screen until the fragments are loaded.

请参阅最后一个问题，因为我知道这是不可能修复加载时间：

Please refer to last question as I understand it's not possible to fix the loading times:

的问题： 有没有一种方法来创建一个 ViewPager 几乎空白片段（仅适用于每一个单独的标题），$ P $他们psent给用户，然后，经过活动已加载并可见（而不是黑屏显示），present一个对话框和填充片段，而对话框显示？

The Question: Is there a way to create a ViewPager with almost empty fragments(only a separate headline for each one), present them to the user and then, after the activity is already loaded and visible (and not a black screen is shown), present a Dialog and populate the fragments in while the Dialog is shown?

任何帮助将是AP preciated。

Any help would be appreciated.

感谢。

推荐答案

由于您使用寻呼机，加载更多的则只是在第一个片段，当您启动该活动。 使最初的片段视图一个进度条可见和表隐藏起来，只加载数据，当您切换到该片段。

Since you use pager, you load more then just the first fragment when you start the activity. Make the initial fragment view with a progress bar visible and the table hidden and load the data only when you switch to that Fragment.

在活动中使用

        mPager.setOnPageChangeListener(new OnPageChangeListener() {

        @Override
        public void onPageSelected(int position) {
            Fragment f = mAdapter.getFragment(mPager.getCurrentItem());
            f.loadData(); // when you finish loading the data, hide the progress bar and show the table

        }

        @Override
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

        }

        @Override
        public void onPageScrollStateChanged(int state) {
        }
    });

要使用mAdapter.getFragment（），从继承适配器：

To use mAdapter.getFragment(), inherit your adapter from:

public abstract class SmartFragmentPagerAdapter extends FragmentPagerAdapter{

private SparseArray<String> mFragmentTags;
private FragmentManager mFragmentManager;

public SmartFragmentPagerAdapter(FragmentManager fragmentManager) {
    super(fragmentManager);
    mFragmentManager = fragmentManager;
    mFragmentTags = new SparseArray<String>();
}

@Override
public Object instantiateItem(ViewGroup container, int position) {
    Object obj = super.instantiateItem(container, position);
    if (obj instanceof Fragment) {
        // record the fragment tag here.
        Fragment f = (Fragment) obj;
        String tag = f.getTag();
        mFragmentTags.put(position, tag);
    }
    return obj;
}

public Fragment getFragment(int position) {
    String tag = mFragmentTags.get(position);
    if (tag == null)
        return null;
    return mFragmentManager.findFragmentByTag(tag);
}

public FragmentManager getFragmentManager(){
    return mFragmentManager;
}

}

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