我正在调用主要活动中的另一个活动，以便在后台下载报价。它有时工作正常，但是如果用户按下后退按钮并离开应用程序，则尝试再次打开应用程序，有时应用程序崩溃并出现以下错误。
我添加了错误的logcat以及我从主活动调用的类。我的代码崩溃应用程序有什么问题？
我从主要活动中调用的课程
private class CheckUpdates extends AsyncTask<String, Void, Void> {
ProgressDialog mProgressDialog;
@Override
protected void onPostExecute(Void result) {
mProgressDialog.dismiss();
Log.d("DESOLF", "dismiss loading dialog");
if (json != null) {
if (jsonResultNull.equals("true")) {
AlertDialog.Builder builder = new AlertDialog.Builder(
context);
builder.setTitle("Check Updates");
builder.setMessage("There are not any updates!");
builder.setNeutralButton("OK",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,
int id) {
}
});
if(SettingsActivity.tocheck==1){
builder.show();
}
} else if(SettingsActivity.tocheck==1) {
AlertDialog.Builder builder = new AlertDialog.Builder(
context);
builder.setTitle("New Data Available");
String messageTxt = "";
if (authors.length() != 0 && quotes.length() != 0) {
messageTxt = String.valueOf(authors.length())
+ " Categories and "
+ String.valueOf(quotes.length()) + " Quotes";
} else if (authors.length() != 0 && quotes.length() == 0) {
messageTxt = String.valueOf(authors.length())
+ " Categories";
} else if (authors.length() == 0 && quotes.length() != 0) {
messageTxt = String.valueOf(quotes.length())
+ " Status";
}
builder.setMessage("There are new " + messageTxt
+ " Arrived. Download?");
builder.setPositiveButton("Yes",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,
int id) {
Log.d("DESOLF", "start updates service");
Intent getUpdates = new Intent(context,
GetUpdatesService.class);
jsonString = json.toString();
//getUpdates.putExtra("json", json.toString());
context.startService(getUpdates);
}
});
builder.setNegativeButton("No",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,
int id) {
}
});
builder.show();
}
else if(SettingsActivity.tocheck==0)
{
Log.d("DESOLF", "start updates service");
Intent getUpdates = new Intent(context,
GetUpdatesService.class);
jsonString = json.toString();
//getUpdates.putExtra("json", json.toString());
context.startService(getUpdates);
}
} else {
AlertDialog.Builder builder = new AlertDialog.Builder(context);
builder.setTitle("Internet Connection Error");
builder.setMessage("Please connect to an internet connection!");
builder.setNeutralButton("OK",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
}
});
builder.show();
}
}
// ------------------------------------------------------------------------
@Override
protected void onPreExecute() {
Log.d("DESOLF", "show loading dialog");
mProgressDialog = ProgressDialog.show(context, "Please Wait",
"Downloading New Status...");
mProgressDialog.setOnKeyListener(new OnKeyListener() {
@Override
public boolean onKey(DialogInterface dialog, int keyCode,
KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK
&& event.getAction() == KeyEvent.ACTION_UP)
mProgressDialog.dismiss();
return false;
}
});
}
我的错误logcat：
05-05 11:03:33.856: E/AndroidRuntime(19379): FATAL EXCEPTION: main
05-05 11:03:33.856: E/AndroidRuntime(19379): Process: com.example.app, PID: 19379
05-05 11:03:33.856: E/AndroidRuntime(19379): android.view.WindowManager$BadTokenException: Unable to add window -- token android.os.BinderProxy@739b5ae is not valid; is your activity running?
05-05 11:03:33.856: E/AndroidRuntime(19379): at android.view.ViewRootImpl.setView(ViewRootImpl.java:574)
05-05 11:03:33.856: E/AndroidRuntime(19379): at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:282)
05-05 11:03:33.856: E/AndroidRuntime(19379): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:85)
05-05 11:03:33.856: E/AndroidRuntime(19379): at android.app.Dialog.show(Dialog.java:298)
05-05 11:03:33.856: E/AndroidRuntime(19379): at android.app.AlertDialog$Builder.show(AlertDialog.java:993)
05-05 11:03:33.856: E/AndroidRuntime(19379): at com.example.app.UpdateClass$CheckUpdates.onPostExecute(UpdateClass.java:207)
05-05 11:03:33.856: E/AndroidRuntime(19379): at com.example.app.UpdateClass$CheckUpdates.onPostExecute(UpdateClass.java:1)
05-05 11:03:33.856: E/AndroidRuntime(19379): at android.os.AsyncTask.finish(AsyncTask.java:636)
05-05 11:03:33.856: E/AndroidRuntime(19379): at android.os.AsyncTask.access$500(AsyncTask.java:177)
05-05 11:03:33.856: E/AndroidRuntime(19379): at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:653)
05-05 11:03:33.856: E/AndroidRuntime(19379): at android.os.Handler.dispatchMessage(Handler.java:102)
05-05 11:03:33.856: E/AndroidRuntime(19379): at android.os.Looper.loop(Looper.java:135)
05-05 11:03:33.856: E/AndroidRuntime(19379): at android.app.ActivityThread.main(ActivityThread.java:5930)
05-05 11:03:33.856: E/AndroidRuntime(19379): at java.lang.reflect.Method.invoke(Native Method)
05-05 11:03:33.856: E/AndroidRuntime(19379): at java.lang.reflect.Method.invoke(Method.java:372)
05-05 11:03:33.856: E/AndroidRuntime(19379): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1405)
05-05 11:03:33.856: E/AndroidRuntime(19379): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1200)
全班
package com.example.app;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.DialogInterface.OnKeyListener;
import android.content.Intent;
import android.database.Cursor;
import android.os.AsyncTask;
import android.util.Log;
import android.view.KeyEvent;
import android.widget.Button;
import android.widget.Toast;
import com.example.app.R;
public class UpdateClass {
public Context context;
Button zain;
String siteUrl, updatesUrl;
DAO db;
Cursor c;
String auPictureDir;
int lastAuthor, lastQuote;
JSONArray authors = null;
JSONArray quotes = null;
JSONObject json;
static String jsonString;
String jsonResultNull = "";
private ConnectionDetector cd;
Boolean isSDPresent = android.os.Environment.getExternalStorageState()
.equals(android.os.Environment.MEDIA_MOUNTED);
// ==============================================================================
public UpdateClass(Context context) {
this.context = context;
db = new DAO(context);
db.open();
lastAuthor = db.getLastAuthor();
lastQuote = db.getLastQuote();
siteUrl = context.getResources().getString(R.string.siteUrl);
updatesUrl = siteUrl + "site/get_updates/" + String.valueOf(lastAuthor)
+ "/" + String.valueOf(lastQuote);
auPictureDir = siteUrl + "global/uploads/levels/";
}
// ==============================================================================
public void handleUpdates() {
// check first for internet
cd = new ConnectionDetector(context);
if (!cd.isConnectingToInternet()) {
// Internet Connection is not present
AlertDialog.Builder builder = new AlertDialog.Builder(context);
builder.setTitle("Internet Connection Error");
builder.setMessage("Please connect to an internet connection!");
builder.setNeutralButton("OK",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
}
});
builder.show();
} else {
new CheckUpdates().execute(new String[] { updatesUrl });
}
}
public static String getJsonString(){
return jsonString;
}
private class CheckUpdates extends AsyncTask<String, Void, Void> {
ProgressDialog mProgressDialog;
@Override
protected void onPostExecute(Void result) {
mProgressDialog.dismiss();
Log.d("DESOLF", "dismiss loading dialog");
if (json != null) {
if (jsonResultNull.equals("true")) {
AlertDialog.Builder builder = new AlertDialog.Builder(
context);
builder.setTitle("Check Updates");
builder.setMessage("There are not any updates!");
builder.setNeutralButton("OK",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,
int id) {
}
});
if(SettingsActivity.tocheck==1){
builder.show();
}
} else if(SettingsActivity.tocheck==1) {
AlertDialog.Builder builder = new AlertDialog.Builder(
context);
builder.setTitle("New Data Available");
String messageTxt = "";
if (authors.length() != 0 && quotes.length() != 0) {
messageTxt = String.valueOf(authors.length())
+ " Categories and "
+ String.valueOf(quotes.length()) + " Quotes";
} else if (authors.length() != 0 && quotes.length() == 0) {
messageTxt = String.valueOf(authors.length())
+ " Categories";
} else if (authors.length() == 0 && quotes.length() != 0) {
messageTxt = String.valueOf(quotes.length())
+ " Status";
}
builder.setMessage("There are new " + messageTxt
+ " Arrived. Download?");
builder.setPositiveButton("Yes",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,
int id) {
Log.d("DESOLF", "start updates service");
Intent getUpdates = new Intent(context,
GetUpdatesService.class);
jsonString = json.toString();
//getUpdates.putExtra("json", json.toString());
context.startService(getUpdates);
}
});
builder.setNegativeButton("No",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,
int id) {
}
});
builder.show();
}
else if(SettingsActivity.tocheck==0)
{
Log.d("DESOLF", "start updates service");
Intent getUpdates = new Intent(context,
GetUpdatesService.class);
jsonString = json.toString();
//getUpdates.putExtra("json", json.toString());
context.startService(getUpdates);
}
} else {
AlertDialog.Builder builder = new AlertDialog.Builder(context);
builder.setTitle("Internet Connection Error");
builder.setMessage("Please connect to an internet connection!");
builder.setNeutralButton("OK",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
}
});
if(!CheckUpdates.isFinishing()){
builder.show();
}
}
}
// ------------------------------------------------------------------------
@Override
protected void onPreExecute() {
Log.d("DESOLF", "show loading dialog");
mProgressDialog = ProgressDialog.show(context, "Please Wait",
"Downloading New Status...");
mProgressDialog.setOnKeyListener(new OnKeyListener() {
@Override
public boolean onKey(DialogInterface dialog, int keyCode,
KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK
&& event.getAction() == KeyEvent.ACTION_UP)
mProgressDialog.dismiss();
return false;
}
});
}
// ------------------------------------------------------------------------
@Override
protected Void doInBackground(String... params) {
// Creating JSON Parser instance
JSONParser jParser = new JSONParser();
// getting JSON string from URL
// Log.e("url", params[0]);
Log.d("DESOLF", "url : params[0]");
json = jParser.getJSONFromUrl(params[0]);
Log.d("DESOLF", "json string has been downloaded");
try {
if (json != null) {
authors = json.getJSONArray("authors");
quotes = json.getJSONArray("quotes");
// Log.e("quotes", String.valueOf(quotes.length()));
if (authors.length() == 0 && quotes.length() == 0) {
jsonResultNull = "true";
}
} else {
jsonResultNull = "true";
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
}
}
答案 0 :(得分：2)
无论您在何处添加builder.show（），请说明活动是否完成的条件。
将您的上下文引用更改为UpdateClass构造函数中的Activity：
public UpdateClass(Activity context) {
//this.context also should be Activity, so please make it as a Activity Reference
this.context = context;
db = new DAO(context);
db.open();
lastAuthor = db.getLastAuthor();
lastQuote = db.getLastQuote();
siteUrl = context.getResources().getString(R.string.siteUrl);
updatesUrl = siteUrl + "site/get_updates/" + String.valueOf(lastAuthor)
+ "/" + String.valueOf(lastQuote);
auPictureDir = siteUrl + "global/uploads/levels/";
}
像：
if(!context.isFinishing()){ //here activity means your activity class
builder.show();
}
答案 1 :(得分：0)
将整个CheckUpdates类复制到MainActivity类中，并在CheckUpdates类中使用MainActivity.this而不是上下文。