首先 - 任何提示/帮助都表示赞赏。
对于这个问题 - 我正在创建一个应用程序，它不断向共享首选项文件添加位置（以及位置名称和日期）。这些位置将保存为位置日志，并在列表视图中显示给用户。用户可以点击任何位置，他们将被传递到选定的项目详细信息页面，在这里他们可以更改位置的名称，导航到该位置甚至删除位置。
问题是，当用户删除位置时，共享首选项文件已正确更新但程序崩溃。我不知道它为什么这样做，我尝试使用Toasts进行调试，但这并没有那么好用。
我附加了处理单项描述视图的java代码。处理删除功能的部分是＆＃34; onClickDelete＆＃34;方法。那里有些不对劲。
P.S - 我尝试使用editor.commit（）和editor.apply（），两者都没有阻止程序崩溃。
package com.android.ict.seneca.androidpocketguide;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.res.TypedArray;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.Gravity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.AutoCompleteTextView;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.List;
public class Websites extends Activity
implements AdapterView.OnItemClickListener{
private final String CLASS_NAME = "Websites";
private int request_Code = 1;
DateFormat df = new SimpleDateFormat("EEE, d MMM yyyy, HH:mm");
String date;
String location;
String name;
String favourite;
int counter;
List listName;
ImageView image1;
ImageView image2;
String [] favo = new String [100];
String [] unfavo = new String [100];
int c1 = 0;
int c2 = 0;
SharedPreferences.Editor editor;
private SharedPreferences savedState;
private ListView listView;
private List<RowItem> rowItems;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_websites);
listName= new ArrayList();
String app_name = "//sdcard//LocoLog.txt";
//int counter = 0, flag = 0;
String temp = "";
savedState = getSharedPreferences( "quantitySaved", MODE_PRIVATE );
editor = savedState.edit();
rowItems = new ArrayList<RowItem>();
counter = savedState.getInt("counter", -1 );
//Toast.makeText(this,"Websites: " + counter,Toast.LENGTH_LONG).show();
if(counter!=-1)
{
for (int i = 1; i <= counter; i++) {
String na;
String da;
String lo;
String fa;
na = "name" + i;
da = "date" + i;
lo = "location" + i;
fa = "favourite" + i;
name = savedState.getString(na, "na");
//name = "Name: " + name;
date = savedState.getString(da, "da");
//date = "Date: " + date;
location = savedState.getString(lo, "lo");
//location = "Location: " + location;
favourite = savedState.getString(fa, "fa");
//Toast.makeText(this, "name: " + name, Toast.LENGTH_LONG).show();
if(favourite.equals("Yes"))
{
favo[c1] = name + "]" + location + "]" + date + "]" + favourite + "]" + counter;
//Toast.makeText(this, "favo[" + c1 + "]: " + favo[c1], Toast.LENGTH_LONG).show();
c1++;
}
else if(favourite.equals("No"))
{
unfavo[c2] = name + "]" + location + "]" + date + "]" + favourite + "]" + counter;
//Toast.makeText(this, "unfavo[" + c2 + "]: " + unfavo[c2], Toast.LENGTH_LONG).show();
c2++;
}
else
{
Toast.makeText(this, "ERROR: Favourite value is wrong!",Toast.LENGTH_LONG).show();
}
//Toast.makeText(this, "The data: "+name + " " + location + " " + date,Toast.LENGTH_LONG).show();
//listName.add(new RowItem(name, location, date, counter));
}
}
else
{
Toast.makeText(this, "No locations saved yet",Toast.LENGTH_LONG).show();
}
int co;
String[] separated1 = new String[5];
String[] separated2 = new String[5];
for(int i = 0; i < c1; i++)
{
separated1 = favo[i].split("]");
co = Integer.parseInt(String.valueOf(separated1[4]));
Toast.makeText(this, "name: " + separated1[0] + " location: " + separated1[1] + " date: " + separated1[2] + " favourite: " + separated1[3] + " counter: " +separated1[4] ,Toast.LENGTH_LONG).show();
listName.add(new RowItem(separated1[0], separated1[1], separated1[2], separated1[3], co));
}
for(int i = 0; i < c2; i++)
{
separated2 = unfavo[i].split("]");
co = Integer.parseInt(String.valueOf(separated1[4]));
Toast.makeText(this, "name: " + separated2[0] + " location: " + separated2[1] + " date: " + separated2[2] + " favourite: " + separated2[3] + " counter: " + separated1[4],Toast.LENGTH_LONG).show();
listName.add(new RowItem(separated2[0], separated2[1], separated2[2], separated2[3], co));
}
listView = (ListView) findViewById(R.id.locationList);
//image1 = (ImageView) findViewById(R.id.imageview1);
//image1.setImageResource(R.drawable.pic1);
listView.setAdapter( new CustomListAdapter(this, R.layout.list_item, listName ) );
listView.setOnItemClickListener(this);
}
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
String s = String.valueOf(parent.getItemAtPosition(position));
Intent myIntent = new Intent(view.getContext(), SingleListItem.class);
myIntent.putExtra("product", s);
String p = String.valueOf(position); //convert position from int to String
myIntent.putExtra("position", p);
startActivityForResult(myIntent, 0);
}
public void onClickDelete(View view)
{
editor.clear().commit();
//String cities = String.valueOf(parent.getItemAtPosition(position));
Toast.makeText(this, "All Locations Deleted", Toast.LENGTH_LONG).show();
startActivityForResult(new Intent(this,Websites.class ),request_Code);
//rowItems.remove(position);
}
public void onClickHome(View view)
{
Toast.makeText(this, "Home button pressed ", Toast.LENGTH_LONG).show();
startActivityForResult(new Intent(this,MainActivity.class ),request_Code);
}
public void onStart() {
super.onStart();
Log.d(CLASS_NAME, "onStart invoked!");
}
public void onPause() {
super.onPause();
Log.d(CLASS_NAME, "onPause invoked!!");
}
public void onResume() {
super.onResume();
Log.d(CLASS_NAME, "onResume invoked!!");
}
public void onStop() {
super.onStop();
Log.d(CLASS_NAME, "onStop invoked!!!");
}
public void onDestroy() {
super.onDestroy();
Log.d(CLASS_NAME, "onDestroy INVOKED!!!");
}
public void onRestart() {
super.onRestart();
Log.d(CLASS_NAME, "onRestart invoked!!");
}
}
堆栈:(这指向此行：counter = savedState.getInt（＆＃34; counter＆＃34;， - 1）;
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.android.ict.seneca.androidpocketguide, PID: 6739
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.android.ict.seneca.androidpocketguide/com.android.ict.seneca.androidpocketguide.Websites}: java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Integer
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Integer
at android.app.SharedPreferencesImpl.getInt(SharedPreferencesImpl.java:242)
at com.android.ict.seneca.androidpocketguide.Websites.onCreate(Websites.java:78)
at android.app.Activity.performCreate(Activity.java:6237)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.-wrap11(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)