Question

我正在使用SharedPreferences保存并在应用程序关闭或启动时将变量保存到我的应用程序中。

我对所有变量都使用相同类型的方法/代码，除了一个变量外，它均有效。

我认为可能是问题所在，该变量也被编程为每天的特定时间重置为= 0。（我为此使用BroadcastReceiver）。

由于这是我在特定时间重置的唯一变量，并且当我尝试使用SharedPreferences保存该变量时，该变量崩溃了，所以这两个方面可能会使我的应用感到生气。

  SharedPreferences settings2= getSharedPreferences(PREFS_NAME,0);

特别是下面的这一行代码似乎使应用程序崩溃

dosesTaken = settings2.getInt("dosesTaken",dosesTaken);

这是“ BroadcastReciver”的类

import ...

public class AlarmResetTaken extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        MainActivity.dosesTaken = 0;
        MainActivity.setDosage();
        Activity2.takenDoseText.setText (Integer.toString(MainActivity.dosesTaken));
    }
}

这是MainActivity中“ BroadcastReciver”的方法

private void setAlarmResetDose(long timeInMillis) {
    AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
    Intent intent = new Intent(this, AlarmResetTaken.class);    
    PendingIntent pendingIntent = PendingIntent.getBroadcast(this,0,intent,0);    
    alarmManager.setRepeating(AlarmManager.RTC, timeInMillis, AlarmManager.INTERVAL_DAY, pendingIntent);
}

以及设置特定时间重置的方法。

public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
    timeDoseResetHour = hourOfDay;
    timeDoseResetMin = minute;    
    timeDoseResetText.setText( String.format("%02d",hourOfDay) +" : " + String.format("%02d",minute));

        Calendar calendar = Calendar.getInstance();
        calendar.set(
                calendar.get(Calendar.YEAR),
                calendar.get(Calendar.MONTH),
                calendar.get(Calendar.DAY_OF_MONTH),
                hourOfDay,
                minute,
                0
        );
        setAlarmResetDose(calendar.getTimeInMillis()); }

这是我得到的错误：

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.dex, PID: 28325
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.dex/com.example.dex.MainActivity}: java.lang.ClassCastException: java.lang.Long cannot be cast to java.lang.Integer
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2913)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3048)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1808)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:6669)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
     Caused by: java.lang.ClassCastException: java.lang.Long cannot be cast to java.lang.Integer
        at android.app.SharedPreferencesImpl.getInt(SharedPreferencesImpl.java:302)
        at com.example.dex.MainActivity.onCreate(MainActivity.java:92)
        at android.app.Activity.performCreate(Activity.java:7136)
        at android.app.Activity.performCreate(Activity.java:7127)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1271)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2893)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3048) 
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78) 
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108) 
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1808) 
        at android.os.Handler.dispatchMessage(Handler.java:106) 
        at android.os.Looper.loop(Looper.java:193) 
        at android.app.ActivityThread.main(ActivityThread.java:6669)

Answer 1

根据您发布的错误，

java.lang.ClassCastException: java.lang.Long cannot be cast to java.lang.Integer

似乎dosesTaken的类型是Long而不是int。因此，当您尝试获取名称为dosesTaken的Integer时，它将引发错误。

因此，要解决该错误，请更改

settings2.getInt("dosesTaken",dosesTaken);

到

settings2.getLong("dosesTaken",dosesTaken);

OR

将dosesTaken的类型更改为int。

Answer 2

更改此-：

settings2.getInt("dosesTaken",dosesTaken);

至：

settings2.getLong("dosesTaken",dosesTaken);

Answer 3

剂量类型长吗？如果是这样，则很有可能将其保存为long，现在您正尝试将其检索为int类型，从而导致ClassCastException。尝试清除您的共享首选项，然后重新运行该应用程序。

使用SharedPreferences保存变量会使我的应用崩溃

3 个答案: