1

关于我的实施的另一个问题。我对来自 ac/c++ 背景的 java/android 相当陌生。我已经在我的代码中实现了这个，我只是遇到了几个问题，并且想知道这是否是最好的解决方案，以及是否有人有任何建议或可以帮助我解决我的问题。这是问题和我的问题：

我的 android 应用程序需要具有从 xml 文件加载设置的能力，并且应用程序需要允许用户更改这些设置并记住更改后的设置。我还需要我的应用程序引用这些更改并检测用户何时更改了其中一项设置。

我目前有上述工作，除了我希望从我的 xml 文件加载默认设置而不是我的代码中使用的方法（查看代码以了解我在说什么）。我已经四处寻找这个，似乎无法找到解决方案。

一旦检测到更改，我需要它将值加载到我的 DataRobot 类变量中。我有这个访问器函数（见代码）。但是，当我尝试更改任何设置时，它不会更改我的 DataRobot 类中的值。

这两个块引号基本上解释了我需要什么。我目前正在使用 android 首选项来解决这个问题。这会是解决这个问题的最好方法吗？

如果您需要任何其他信息，请告诉我。提前感谢您的帮助，非常感谢！

另外，我目前在当前设置中遇到了一些错误，下面列出了错误发生时间和所述错误的日志 cat 的说明。

下面的 log cat 输出发生在应用程序首次启动时。看来它在转换字符串时遇到了问题并抛出了 ClassCastException。我不确定在哪里或为什么会发生这种情况。所有代码都在帖子的底部。

02-03 20:05:50.731: INFO/System.out(279): debugger has settled (1384)
02-03 20:05:52.080: INFO/ActivityManager(59): Displayed activity com.android.launcher/com.android.launcher2.Launcher: 38755 ms (total 38755 ms)
02-03 20:05:52.480: WARN/Resources(279): Converting to string: TypedValue{t=0x10/d=0x3c a=-1}
02-03 20:05:52.669: WARN/System.err(279): java.lang.ClassCastException: java.lang.String
02-03 20:05:52.689: WARN/System.err(279):     at android.app.ContextImpl$SharedPreferencesImpl.getInt(ContextImpl.java:2706)
02-03 20:05:52.689: WARN/System.err(279):     at cpe495.smartapp.SmartApp.onCreate(SmartApp.java:61)
02-03 20:05:52.701: WARN/System.err(279):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
02-03 20:05:52.715: WARN/System.err(279):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
02-03 20:05:52.720: WARN/System.err(279):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
02-03 20:05:52.729: WARN/System.err(279):     at android.app.ActivityThread.access$2300(ActivityThread.java:125)
02-03 20:05:52.729: WARN/System.err(279):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
02-03 20:05:52.750: WARN/System.err(279):     at android.os.Handler.dispatchMessage(Handler.java:99)
02-03 20:05:52.750: WARN/System.err(279):     at android.os.Looper.loop(Looper.java:123)
02-03 20:05:52.760: WARN/System.err(279):     at android.app.ActivityThread.main(ActivityThread.java:4627)
02-03 20:05:52.771: WARN/System.err(279):     at java.lang.reflect.Method.invokeNative(Native Method)
02-03 20:05:52.781: WARN/System.err(279):     at java.lang.reflect.Method.invoke(Method.java:521)
02-03 20:05:52.781: WARN/System.err(279):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
02-03 20:05:52.799: WARN/System.err(279):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
02-03 20:05:52.799: WARN/System.err(279):     at dalvik.system.NativeStart.main(Native Method)
02-03 20:05:57.439: DEBUG/KeyguardViewMediator(59): pokeWakelock(5000)
02-03 20:05:57.630: DEBUG/KeyguardViewMediator(59): pokeWakelock(5000)
02-03 20:05:57.759: INFO/ActivityManager(59): Displayed activity cpe495.smartapp/.SmartApp: 10694 ms (total 10694 ms)
02-03 20:05:57.940: INFO/ARMAssembler(59): generated scanline__00000077:03545404_00000004_00000000 [ 47 ipp] (67 ins) at [0x2bd108:0x2bd214] in 2142171 ns
02-03 20:05:58.029: INFO/ARMAssembler(59): generated scanline__00000177:03515104_00001001_00000000 [ 91 ipp] (114 ins) at [0x2bd218:0x2bd3e0] in 1052927 ns

下面的日志猫是用户使用首选项菜单更改首选项中的 HeartRateBase 值后打印出来的。它似乎发生在 onpreferenceschanged 函数内部。

02-03 20:06:19.000: VERBOSE/onsharedpreferencechanged(279): inside
02-03 20:06:19.009: WARN/System.err(279): java.lang.ClassCastException: java.lang.String
02-03 20:06:19.019: WARN/System.err(279):     at android.app.ContextImpl$SharedPreferencesImpl.getInt(ContextImpl.java:2706)
02-03 20:06:19.031: WARN/System.err(279):     at cpe495.smartapp.SmartApp.onSharedPreferenceChanged(SmartApp.java:131)
02-03 20:06:19.040: WARN/System.err(279):     at android.app.ContextImpl$SharedPreferencesImpl$EditorImpl.commit(ContextImpl.java:2830)
02-03 20:06:19.040: WARN/System.err(279):     at android.preference.Preference.tryCommit(Preference.java:1198)
02-03 20:06:19.050: WARN/System.err(279):     at android.preference.Preference.persistString(Preference.java:1225)
02-03 20:06:19.060: WARN/System.err(279):     at android.preference.ListPreference.setValue(ListPreference.java:126)
02-03 20:06:19.070: WARN/System.err(279):     at android.preference.ListPreference.onDialogClosed(ListPreference.java:220)
02-03 20:06:19.120: WARN/System.err(279):     at android.preference.DialogPreference.onDismiss(DialogPreference.java:384)
02-03 20:06:19.139: WARN/System.err(279):     at android.app.Dialog$ListenersHandler.handleMessage(Dialog.java:1047)
02-03 20:06:19.149: WARN/System.err(279):     at android.os.Handler.dispatchMessage(Handler.java:99)
02-03 20:06:19.149: WARN/System.err(279):     at android.os.Looper.loop(Looper.java:123)
02-03 20:06:19.170: WARN/System.err(279):     at android.app.ActivityThread.main(ActivityThread.java:4627)
02-03 20:06:19.170: WARN/System.err(279):     at java.lang.reflect.Method.invokeNative(Native Method)
02-03 20:06:19.180: WARN/System.err(279):     at java.lang.reflect.Method.invoke(Method.java:521)
02-03 20:06:19.190: WARN/System.err(279):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
02-03 20:06:19.200: WARN/System.err(279):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
02-03 20:06:19.200: WARN/System.err(279):     at dalvik.system.NativeStart.main(Native Method)
02-03 20:06:19.320: WARN/InputManagerService(59): Window already focused, ignoring focus gain of: com.android.internal.view.IInputMethodClient$Stub$Proxy@43e60f18

从这里开始是我针对这些问题的代码。

//The Main Class, mainly my gui class
public class SmartApp extends Activity implements OnSharedPreferenceChangeListener {

    private DataRobot dR = new DataRobot();
    public SmartApp() {}
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.intro);

        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
        PreferenceManager.setDefaultValues(this, R.xml.settings, false);
        prefs.registerOnSharedPreferenceChangeListener(this);

        //set remembered preferences
        try {
            dR.sethRB(prefs.getInt("heartRateBaseKey", 60));
            dR.sethRVMax(prefs.getInt("hRVMaxKey", 100));
            dR.sethRVMin(prefs.getInt("hRVMinKey", 0));
            dR.setsI1(prefs.getInt("sI1Key", 50));
            dR.setsI2(prefs.getInt("sI2Key", 80));
            dR.setW1(prefs.getInt("weight1Key", 20));
            dR.setW2(prefs.getInt("weight2Key", 40));
            dR.setW3(prefs.getInt("weight3Key", 60));
        }
        catch (ClassCastException e) {
            e.printStackTrace();
        }

        final Button smartConnectionSettingsButton = (Button) findViewById(R.id.smartConnectionSettingsButton);
        smartConnectionSettingsButton.setOnClickListener(
                new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        // TODO Auto-generated method stub
                        Intent settingsIntent = new Intent(v.getContext(), Settings.class);
                        startActivityForResult(settingsIntent, 0);
                    }
                });
    }
    @Override
    public void onSharedPreferenceChanged(SharedPreferences prefs,
            String key) {
        // TODO Auto-generated method stub
        Log.v("onsharedpreferencechanged", "inside");
        try {
            if(key.equals("heartRateBaseKey")) {
                dR.sethRB(prefs.getInt("heartRateBaseKey", 60));
            }
            else if(key.equals("hRVMaxKey")) {
                dR.sethRVMax(prefs.getInt("hRVMaxKey", 100));
            }
            else if(key.equals("hRVMinKey")) {
                dR.sethRVMin(prefs.getInt("hRVMinKey", 0));
            }
            else if(key.equals("sI1Key")) {
                dR.setsI1(prefs.getInt("sI1Key", 50));
            }
            else if(key.equals("sI2Key")) {
                dR.setsI2(prefs.getInt("sI2Key", 80));
            }
            else if(key.equals("weight1Key")) {
                dR.setW1(prefs.getInt("weight1Key", 20));
            }
            else if(key.equals("weight2Key")) {
                dR.setW2(prefs.getInt("weight2Key", 40));
            }
            else if(key.equals("weight3Key")) {
                dR.setW3(prefs.getInt("weight3Key", 60));
            }
        }
        catch (ClassCastException e) {
            e.printStackTrace();
        }

    }
}

这个类是我分析数据的地方，我需要在应用程序启动时设置这里的私人信息。目前我在 SmartApp 的 onCreate 方法中这样做。如果用户在运行时更改任何首选项，我还需要实时更改值。

public class DataRobot {
    /* This class is for analyzing the data */
    private SmartDataObject data;

    private int sI1;
    private int sI2;
    private int w1;
    private int w2;
    private int w3;
    private int hRB;
    private int hRVMin;
    private int hRVMax;
    public boolean analyzeData(SmartDataObject temp) {}

    public void setsI1(int temp) {
        sI1 = temp;
    }
    public void setsI2(int temp) {
        sI2 = temp;
    }
    public void setW1(int temp) {
        w1 = temp;
    }
    public void setW2(int temp) {
        w2 = temp;
    }
    public void setW3(int temp) {
        w3 = temp;
    }
    public void sethRB(int temp) {
        hRB = temp;
    }
    public void sethRVMin(int temp) {
        hRVMin = temp;
    }
    public void sethRVMax(int temp) {
        hRVMax = temp;
    }
}

下面是首选项类 

import android.os.Bundle;
import android.preference.PreferenceActivity;

public class Preferences extends PreferenceActivity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        addPreferencesFromResource(R.xml.settings);
    }
}

下面是我的首选项的 XML 文件，名为“settings.xml”。 

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen
  xmlns:android="http://schemas.android.com/apk/res/android">
<PreferenceCategory android:title="Profile Settings">
<EditTextPreference 
android:title="First Name" 
android:key="firstNameKey" 
android:selectable="false"></EditTextPreference>
<EditTextPreference 
android:title="Last Name" 
android:key="lastNameKey" 
android:selectable="false"></EditTextPreference>
<EditTextPreference 
android:title="User Name" 
android:key="userNameKey" 
android:selectable="false"></EditTextPreference>
<EditTextPreference 
android:title="Birth Date" 
android:key="birthDateKey" 
android:selectable="false"></EditTextPreference>
</PreferenceCategory>
<PreferenceCategory 
android:title="Configuration Settings">
<ListPreference 
android:title="Medium Stress Index Threshold" 
android:entryValues="@array/sI1Values" 
android:entries="@array/sI1Array" 
android:key="sI1Key"></ListPreference>
<ListPreference 
android:title="High Stress Index Threshold" 
android:entryValues="@array/sI1Values" 
android:entries="@array/sI1Array" 
android:key="sI2Key"></ListPreference>
<EditTextPreference 
android:title="Weight 1" 
android:key="weight1Key"></EditTextPreference>
<EditTextPreference 
android:title="Weight 2" 
android:key="weight2Key"></EditTextPreference>
<EditTextPreference 
android:title="Weight 3" 
android:key="weight3Key"></EditTextPreference>    
<ListPreference
android:entryValues="@array/heartRateBaseValues" 
android:entries="@array/heartRateBaseArray" 
android:defaultValue="60" 
android:key="heartRateBaseKey" 
android:title="Heart Rate Base"></ListPreference>
<EditTextPreference 
android:title="Heart Rate Variability Minimum" 
android:key="hRVMinKey"></EditTextPreference>
<EditTextPreference 
android:title="Heart Rate Variability Maximum" 
android:key="hRVMaxKey"></EditTextPreference>    
</PreferenceCategory>
</PreferenceScreen>

下面是“arrayValues.xml”文件，其中包含一些东西的一些值。 

<?xml version="1.0" encoding="utf-8"?>
<resources>
<string-array name="heartRateBaseArray">
<item>10 bpm</item>
<item>20 bpm</item>
<item>30 bpm</item>
<item>40 bpm</item>
<item>50 bpm</item>
<item>60 bpm</item>
<item>70 bpm</item>
<item>80 bpm</item>
<item>90 bpm</item>
<item>100 bpm</item>
</string-array>
<string-array name="heartRateBaseValues">
<item>10</item>
<item>20</item>
<item>30</item>
<item>40</item>
<item>50</item>
<item>60</item>
<item>70</item>
<item>80</item>
<item>90</item>
<item>100</item>
</string-array>
<string-array name="sI1Array">
<item>0</item>
<item>5</item>
<item>10</item>
<item>15</item>
<item>20</item>
<item>25</item>
<item>30</item>
<item>35</item>
<item>40</item>
<item>45</item>
<item>50</item>
<item>55</item>
<item>60</item>
<item>65</item>
<item>70</item>
<item>75</item>
<item>80</item>
<item>85</item>
<item>90</item>
<item>95</item>
<item>100</item>
</string-array>
<string-array name="sI1Values">
<item>0</item>
<item>5</item>
<item>10</item>
<item>15</item>
<item>20</item>
<item>25</item>
<item>30</item>
<item>35</item>
<item>40</item>
<item>45</item>
<item>50</item>
<item>55</item>
<item>60</item>
<item>65</item>
<item>70</item>
<item>75</item>
<item>80</item>
<item>85</item>
<item>90</item>
<item>95</item>
<item>100</item>
</string-array>
</resources>
4

2 回答 2

1

无需深入研究您的代码。我将首先查看 SmartApp 代码中的第 61 和 131 行。这是两种情况下异常开始的地方。如果在这两种情况下这都指向使用的调用prefs.getInt()，我猜想这与您要求的有关int，而实际上原始 XML 条目是字符串。

于 2011-02-04T03:52:17.973 回答
1

For your error, I have had a similar problem with my applications and the way I got around this was retrieving the preferences as String objects and then using Integer.parse() to convert the String to a number. It's a bit of a hack but it got the job done for me.

As for your initial question could you maybe have your PreferenceActivity write to a certain specific file when a change is made that the other Activity can check periodically or on it's creation and adjust/pull information accordingly?

于 2011-02-04T03:53:04.650 回答