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我需要一个带有固定标题的可滚动表，所以我遵循this great blog，一切都很好。Android的onLayout（）和AsyncTask（）不能一起工作
这个想法是使用一个表格作为标题，一个表格用于在scrollview中添加的内容，它们都在自定义的LinearLayout中。在定制的LinearLayout中，我们将覆盖onLayout（）以获取每行的最大宽度，并为标题和内容表的每一行设置宽度。
这里是活动及其布置：
package com.stylingandroid.ScrollingTable;
import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.TableLayout;
import android.widget.TableRow;
public class ScrollingTable extends LinearLayout
{
public ScrollingTable(Context context)
{
super(context);
}
public ScrollingTable(Context context, AttributeSet attrs)
{
super(context, attrs);
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b)
{
super.onLayout(changed, l, t, r, b);
TableLayout header = (TableLayout) findViewById(R.id.HeaderTable);
TableLayout body = (TableLayout) findViewById(R.id.BodyTable);
if (body.getChildCount() > 0) {
TableRow bodyRow = (TableRow) body.getChildAt(0);
TableRow headerRow = (TableRow) header.getChildAt(0);
for (int cellnum = 0; cellnum < bodyRow.getChildCount(); cellnum++){
View bodyCell = bodyRow.getChildAt(cellnum);
View headerCell = headerRow.getChildAt(cellnum);
int bodyWidth = bodyCell.getWidth();
int headerWidth = headerCell.getWidth();
int max = Math.max(bodyWidth, headerWidth);
TableRow.LayoutParams bodyParams = (TableRow.LayoutParams)bodyCell.getLayoutParams();
bodyParams.width = max;
TableRow.LayoutParams headerParams = (TableRow.LayoutParams)headerCell.getLayoutParams();
headerParams.width = max;
}
}
}
}
main.xml中
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<com.stylingandroid.ScrollingTable.ScrollingTable
android:layout_width="match_parent"
android:orientation="vertical"
android:layout_height="match_parent">
<TableLayout
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:id="@+id/HeaderTable">
</TableLayout>
<ScrollView
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TableLayout
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:id="@+id/BodyTable">
</TableLayout>
</ScrollView>
</com.stylingandroid.ScrollingTable.ScrollingTable>
</LinearLayout>
主要业务
package com.stylingandroid.ScrollingTable;
import android.app.Activity;
import android.app.ProgressDialog;
import android.graphics.Color;
import android.os.AsyncTask;
import android.os.Bundle;
import android.widget.TableLayout;
import android.widget.TableRow;
import android.widget.TextView;
public class ScrollingTableActivity extends Activity
{
private String[][] tableData = {
{"header11111111111", "header2","header3","header4"},
{"column1", "column1","column1","column1"},
{"column1", "column1","column1","column1"},
{"column1", "column1","column1","column1"},
{"column1", "column1",
"column1","column1"},
{"column1", "column1","column1","column1"},
{"column1", "column1","column1","column1"},
{"column1", "column1","column1","column1"},
{"column1", "column1","column1","column1"},
{"column1", "column1","column1","column1"},
{"column1", "column1","column1","column1"},
{"column1", "column1","column1","column1"},
{"column1", "column1","column1","column1"}
};
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
TableLayout tableHeader = (TableLayout)findViewById(R.id.HeaderTable);
TableLayout tableBody = (TableLayout)findViewById(R.id.BodyTable);
appendRows(tableHeader, tableBody, tableData);
}
private void appendRows(TableLayout tableHeader ,TableLayout tableContent, String[][] amortization) {
int rowSize=amortization.length;
int colSize=(amortization.length > 0)?amortization[0].length:0;
for(int i=0; i<rowSize; i++) {
TableRow row1 = new TableRow(this);
for(int j=0; j<colSize; j++) {
TextView c = new TextView(this);
c.setText(amortization[i][j]);
c.setPadding(3, 3, 3, 3);
if (i == 0) {
c.setTextColor(Color.BLACK);
}
row1.addView(c);
}
if (i == 0) {
row1.setBackgroundColor(Color.LTGRAY);
tableHeader.addView(row1, new TableLayout.LayoutParams());
} else {
tableContent.addView(row1, new TableLayout.LayoutParams());
}
}
}
上述代码工作完美（
），然而，当我使用AnysnTask从服务器获取数据并将数据添加到表中，onLayout（）在我的习惯米视图不再工作。我模拟由登出了一些数量获取数据：
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
new MyTask().execute();
}
private class MyTask extends AsyncTask<Void, Void, Void> {
private ProgressDialog progressDialog;
protected void onPreExecute() {
progressDialog = ProgressDialog.show(ScrollingTableActivity.this,
"", "Loading. Please wait...", true);
}
@Override
protected Void doInBackground(Void... reportTypes) {
for (int i = 0; i < 500; i++) {
System.out.println(i);
}
return null;
}
@Override
protected void onPostExecute(Void result) {
progressDialog.dismiss();
TableLayout tableHeader = (TableLayout)findViewById(R.id.HeaderTable);
TableLayout tableBody = (TableLayout)findViewById(R.id.BodyTable);
appendRows(tableHeader, tableBody, tableData);
}
}
所以onLayout（）时，我打电话从主UI线程appendRows（），将其置于onCreate（）方法才有效。如果我从另一个UI线程（在AsyncTask的onPostExecute（）中调用），调用onLayout（）（我通过创建一些日志来检查它），但它不影响GUI。我试着用invalidate（），forceLayout（），requestLayout（）但不改变任何东西。 
我想我们需要调用一个方法来刷新GUI，但不知道它是什么，我已经在2天内搜索并尝试了很多方法，但没有任何东西，所以它会非常感激如果你可以对此有任何想法。非常感谢。
没有“另一个”UI线程。 'onPostExecute'在与'onCreate'相同的线程上被调用。 – inazaruk 2011-12-23 08:14:15
如果是这样，为什么只要将appendRow放入onCreate中就可以工作。 – thanhbinh84 2011-12-23 08:31:12
我不知道。我没有深入查看你的代码。但是你可能想考虑这个问题而不考虑线程。 – inazaruk 2011-12-23 09:17:09