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我檢查線程中的字符串是否爲NULL，如果它爲null，Handler啓動一個Runnable啓動一個新的Activity。通過Runnable開始新的活動
一切工作正常，但在新的活動顯示後，它切換回調用活動，它崩潰。
這是一段代碼片段。
if(username==null)
{
dialogs.dismiss();
handlers.post(new MyRunable());
}
和Runnable接口是
public class MyRunable implements Runnable
{
public void run(){
Toast.makeText(ListActivity.this, "Your Connection is too slow",Toast.LENGTH_LONG).show();
startActivity(new Intent(ListActivity.this,Anim.class));
}
}
這裏是我的全部來源
package com.cram;
import java.io.File;
import java.io.IOException;
import javax.xml.parsers.ParserConfigurationException;
import org.xml.sax.SAXException;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.Typeface;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
public class BuddyListActivity extends Activity
{
String ss;
private static ProgressDialog dialogs,dialog;
private Thread downloadThreads;
boolean results=false;
Context ctx;
String[]ddd;
ListView lv1;
String [] icons;
BuddyDbAdapter adapter;
NetworkInfo netinfo;
Cursor cursor;
String values;
GetBuddy gb;
BuddyDB db;
String[] username;
String[] firstname;
String[] lastname;
String[] avatar;
String[] id;
File[] iconss;
Handler handlers;
boolean ready=false;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.buddy);
db=new BuddyDB(BuddyListActivity.this);
Typeface font = Typeface.createFromAsset(getAssets(),"fonts/Fortheloveofhate.ttf");
TextView btxt = (TextView) findViewById(R.id.textbuddy);
btxt.setTypeface(font);
ctx=getApplicationContext();
lv1=(ListView)findViewById(R.id.list22);
netinfo=null;
adapter=new BuddyDbAdapter(BuddyListActivity.this);
netinfo=checkDataConnection(getApplicationContext());
handlers = new Handler();
adapter.open();
if(netinfo!=null)
{
downloadThreads = (Thread) getLastNonConfigurationInstance();
if (downloadThreads != null && downloadThreads.isAlive()) {
dialog = ProgressDialog.show(this, "Download", "downloading");
}
startdownload();
}
if(netinfo==null)
{
cursor=adapter.showBuddy();
if (cursor==null||cursor.moveToFirst()==false)
{
AlertDialog.Builder buddybox = new AlertDialog.Builder(this);
buddybox.setMessage("You have No Buddies Yet douche!!");
buddybox.setNeutralButton("Okay", new OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
startActivity(new Intent(getBaseContext(),Anim.class));
}
});
buddybox.setCancelable(false);
buddybox.show();
}
else
{
cursor.moveToFirst();
int j=0;
ddd=new String[cursor.getCount()];
icons=new String [cursor.getCount()];
do
{
String firstName = cursor.getString(cursor.getColumnIndex(BuddyDbAdapter.BUDDY_FISTNAME));
String lastname = cursor.getString(cursor.getColumnIndex(BuddyDbAdapter.BUDDY_LASTNAME));
String Avatar = cursor.getString(cursor.getColumnIndex(BuddyDbAdapter.AVATAR));
ddd[j]=firstName+" "+lastname;
Log.d("Test", ddd[j]);
icons[j]=Avatar;
Log.d("Test", icons[j]);
j++;
}while(cursor.moveToNext());
iconss= new File[icons.length];
Log.d("Test",icons.length+"");
for (int q = 0; q < icons.length; q++) {
iconss[q] = new File(Download.ROOT +"/"+ icons[q]+".jpg");
Log.d("Test", iconss[q].getAbsolutePath().toString());
}
//adapter.close();
lv1.setAdapter(new BuddyAdapter(BuddyListActivity.this,R.layout.list1,ddd,iconss));
onDestroy();
}
}
}
private void box() {
// TODO Auto-generated method stub
cursor=adapter.showBuddy();
if (cursor==null||cursor.moveToFirst()==false)
{
dialogs.dismiss();
AlertDialog.Builder buddybox = new AlertDialog.Builder(this);
buddybox.setMessage("You have No Buddies Yet ass!!");
buddybox.setNeutralButton("Okay", new OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
startActivity(new Intent(getBaseContext(),Anim.class));
}
});
buddybox.setCancelable(false);
buddybox.show();
}
}
private NetworkInfo checkDataConnection(Context applicationContext) {
final ConnectivityManager connMgr = (ConnectivityManager)BuddyListActivity.this.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkinfo=null;
final android.net.NetworkInfo wifi =connMgr.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
final android.net.NetworkInfo mobile =connMgr.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);
if(wifi.isConnected()||mobile.isConnected())
{networkinfo=connMgr.getActiveNetworkInfo();
return networkinfo;
}
else
{
return null;
}
}
@Override
protected void onDestroy() {
super.onDestroy();
if (adapter != null) {
adapter.close();
}
}
@Override
protected void onStop()
{
super.onStop();
finish();
}
private void startdownload() {
dialogs = ProgressDialog.show(BuddyListActivity.this, "Contacting Our Servers", "Geting Your Buddies Avatar");
downloadThreads = new MyThread();
downloadThreads.start();
}
public class MyThread extends Thread {
@Override
public void run() {
try {
new Thread();
GetBuddy tt=new GetBuddy();
String xml=tt.get();
if(xml==null)
{ dialogs.dismiss();
handlers.post(new MyRunable());
ready=false;
//downloadThreads.suspend();
}
final Download cd = new Download();
results = cd.downloadBitmap();
if(results)
{
BuddyParse bp=new BuddyParse();
try {
username=bp.show(xml);
// if(username==null)
// { dialogs.dismiss();
// handlers.post(new MyRunable());
// //downloadThreads.suspend();
// }
firstname=bp.firstname();
lastname=bp.lastname();
avatar=bp.avatar();
id=bp.id();
adapter.deleteAll();
ready=true;
}
catch (ParserConfigurationException e)
{
e.printStackTrace();
}
catch (SAXException e)
{
e.printStackTrace();
}
catch (IOException e)
{
e.printStackTrace();
}
// Log.d("len", username.length+"");
for(int k=0; k<username.length;k++)
{
adapter.insertBuddy(id[k], username[k], firstname[k], lastname[k], avatar[k]);
Log.d("Test", id[k]+username[k]+firstname[k]+lastname[k]+avatar[k]+"");
}
box();
cursor=adapter.showBuddy();
cursor.moveToFirst();
int i=0;
ddd=new String[cursor.getCount()];
icons=new String [cursor.getCount()];
do
{
String firstName = cursor.getString(cursor.getColumnIndex(BuddyDbAdapter.BUDDY_FISTNAME));
String lastname = cursor.getString(cursor.getColumnIndex(BuddyDbAdapter.BUDDY_LASTNAME));
String Avatar = cursor.getString(cursor.getColumnIndex(BuddyDbAdapter.AVATAR));
ddd[i]=firstName+" "+lastname;
Log.d("Test", ddd[i]);
icons[i]=Avatar;
Log.d("Test",icons[i]);
i++;
}while(cursor.moveToNext());
iconss= new File[avatar.length];
for (int k = 0; k < avatar.length; k++) {
iconss[k] = new File(Download.ROOT+"/"+avatar[k]+".jpg");
Log.d("Test", iconss[k].getAbsolutePath()+"thread");
//Log.d("Test", ddd[k]);
}
if (results&&ready)
{
dialogs.dismiss();
handlers.post(new MyRuns());
}
}
// else
// { dialogs.dismiss();
// handlers.post(new MyRunable());
//
// }
}finally {
}
}
}
public class MyRuns implements Runnable {
public void run() {
ready=true;
lv1.setAdapter(new BuddyAdapter(ctx,R.layout.list1,ddd,iconss));
onDestroy();
}
}
public class MyRunable implements Runnable {
public void run() {
//Toast.makeText(BuddyListActivity.this, "Your Connection is too slow", Toast.LENGTH_LONG).show();
startActivity(new Intent(BuddyListActivity.this,Anim.class));
}
}
}
logcat錯誤.... – 2012-01-11 12:01:19
你可以把onStart（）和onCreate（）方法放在第二個activity嗎？也許問題是 – 2012-01-11 12:03:55
你有沒有遇到任何錯誤？ – 2012-01-11 12:12:00