我是android编程的新手。在对 ListView 和 ArrayAdapter 进行了一些研究之后，我决定编写一个简单的演示程序来练习。
我想显示我的自定义视图样式 ListView，所以我重写了 ArrayAdapter 的 getView() 函数。我知道为了防止内存泄漏，应该检查参数convertView，并且只有在convertView为null时才膨胀新对象。我还制作了一个 AsyncTask 以在后台（在 doInBackground 中）继续将数据添加到 ArrayAdapter 中，并将 notifyDataChanged 保留为 ListView（在 onProgressUpdate() 中）。
这是问题所在：当我设置 MAX_ITEM=50（这意味着我将在 AsyncTask 中添加多少数据）时，一切正常。但是当我设置 MAX_ITEM=500 时，logcat 显示错误消息：“原因：android.view.ViewRootImpl$CalledFromWrongThreadException：只有创建视图层次结构的原始线程才能触摸其视图。” 和应用程序关闭。谁能告诉我问题出在哪里？以下是我的源代码“MyTest.java”和我的布局xml文件“main.xml”和“layout_row.xml”，感谢您的观看和帮助。
MyTest.Java：
public class MyTest extends Activity {
private static final String TAG="Tany";
private static final int MAX_ITEM = 50;
private MyArrayAdapter adapter;
private ListView listview;
private int addCounter = 0;
public class MyData implements Comparable<MyData>{
public String str1;
public String str2;
public String str3;
public MyData(String str1, String str2, String str3){
this.str1 = str1;
this.str2 = str2;
this.str3 = str3;
}
@Override
public int compareTo(MyData data) {
// TODO Auto-generated method stub
int result = this.str1.compareTo(data.str1);
return result;
}
}
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
listview = (ListView)findViewById(R.id.listview);
adapter = new MyArrayAdapter(this, R.layout.layout_row);
//set adapter
listview.setAdapter(adapter);
listview.setOnItemClickListener(new AdapterView.OnItemClickListener(){
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
// TODO Auto-generated method stub
Log.d(TAG, "position "+position+" is clicked");
Toast.makeText(parent.getContext(), adapter.getItem(position).str1+", "+adapter.getItem(position).str2, Toast.LENGTH_SHORT).show();
}
});
listview.setTextFilterEnabled(true);
}
public void onStart(){
super.onStart();
MyTask newTask = new MyTask();
newTask.execute();
}
public class MyTask extends AsyncTask<Void, Void, Void>{
@Override
protected Void doInBackground(Void... params) {
// TODO Auto-generated method stub
for(int i = addCounter; i<MAX_ITEM; i++)
{
adapter.add(new MyData("str1="+i,"str2="+i,"str3="+i));
addCounter++;
publishProgress();
}
return null;
}
@Override
protected void onProgressUpdate(Void... progress ){
adapter.notifyDataSetChanged();
}
@Override
protected void onPostExecute(Void result){
Log.d(TAG, "AsyncTask MyTask finsish its work");
}
}
public class MyArrayAdapter extends ArrayAdapter<MyData>{
public MyArrayAdapter(Context context, int textViewResourceId) {
super(context, textViewResourceId);
// TODO Auto-generated constructor stub
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View row;
if(convertView == null){
LayoutInflater inflater = getLayoutInflater();
row = inflater.inflate(R.layout.layout_row, parent, false);
}else{
Log.d(TAG,"recycle view, pos="+position);
row = convertView;
}
TextView tv1 = (TextView) row.findViewById(R.id.textView1);
tv1.setText( ((MyData)getItem(position)).str1 );
TextView tv2 = (TextView) row.findViewById(R.id.textView2);
tv2.setText( ((MyData)getItem(position)).str2 );
TextView tv3 = (TextView) row.findViewById(R.id.textView3);
tv3.setText( ((MyData)getItem(position)).str3 );
return row;
}
}
}
主.xml：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/vertical_container"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView
android:text="@string/list_title_start"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
</TextView>
<ListView
android:id="@+id/listview"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
</ListView>
<TextView
android:text="@string/list_title_end"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
</TextView>
</LinearLayout>
layout_row.xml：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<LinearLayout
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:id="@+id/linearLayout1"
android:orientation="horizontal">
<ImageView
android:layout_height="wrap_content"
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:src="@drawable/ic_launcher">
</ImageView>
<TextView
android:text="TextView1"
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="6dip"
android:layout_marginTop="6dip"
android:textAppearance="?android:attr/textAppearanceLarge">
</TextView>
</LinearLayout>
<LinearLayout
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:id="@+id/linearLayout1"
android:orientation="horizontal">
<TextView
android:id="@+id/textView2"
android:text="TextView"
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:textAppearance="?android:attr/textAppearanceSmall">
</TextView>
<TextView
android:text="TextView"
android:id="@+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceSmall"
android:layout_marginLeft="6dip">
</TextView>
</LinearLayout>
</LinearLayout>