Android onLayout()和AsyncTask()无法一起使用
作者：互联网
我需要一个带有固定标题的可滚动表,所以我遵循this great blog并且一切都很好.
这个想法是使用一个表作为标题,一个表用于在scrollview中添加的内容,它们都在自定义的LinearLayout中.在自定义的LinearLayout中,我们将覆盖onLayout()以获取每行的最大宽度,并为header和content表的每一行设置宽度.
这是活动及其布局：
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>
主要活动
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());
}
}
}
上面的代码完美地工作(),但是,当我使用AnysnTask从服务器获取数据并稍后将数据添加到表时,我的自定义视图中的onLayout()不再起作用.我通过注销一些数字模拟获取数据：
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()只有在我通过将它放在onCreate()方法中从主UI线程调用appendRows()时才有效.如果我从另一个UI线程调用(在AsyncTask的onPostExecute()中),则调用onLayout()(我通过创建一些日志来检查它),但它不会影响GUI.我尝试使用invalidate(),forceLayout(),requestLayout()但不改变任何东西.
我想我们需要调用一个方法来进行GUI刷新,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得到任何结果,所以如果你能给出任何想法我将非常感激对这个.非常感谢.
解决方法:
你可能想看看这个答案：
Android Set textview layout width dynamically
但是,基本上,尝试将每个TextView的宽度设置为与标题相同.
这可能需要你做两次,因为你可能需要让系统进行布局,所以使用View.INVISIBLE,然后你需要退出AsyncTask,调用另一个,这样就可以进行布局工作.
然后在第二个中,您可以获取不可见的表,循环查找该列中的最大宽度,然后将该列中的所有TextView设置为最大.
这不是最好的解决方案,但应该有效.
我认为您在AsyncTask中的主要问题是需要完成布局,然后您可以进行修复.
标签：android,layout,android-asynctask,ui-thread 来源： https://codeday.me/bug/20190630/1335885.html