我扩展了DialogPreference类，并希望我能使解决方案像this一样工作。
我想在我的系统中实现我的TimePreference类，但在调用PreferenceActivity时会出现运行时异常
04-15 16:47:31.555: W/MediaPlayer(28689): mediaplayer went away with unhandled events
04-15 16:47:31.555: W/MediaPlayer(28689): mediaplayer went away with unhandled events
04-15 16:47:31.594: D/libEGL(28689): loaded /system/lib/egl/libGLES_android.so
04-15 16:47:31.609: D/libEGL(28689): loaded /vendor/lib/egl/libEGL_POWERVR_SGX540_120.so
04-15 16:47:31.633: D/libEGL(28689): loaded /vendor/lib/egl/libGLESv1_CM_POWERVR_SGX540_120.so
04-15 16:47:31.637: D/libEGL(28689): loaded /vendor/lib/egl/libGLESv2_POWERVR_SGX540_120.so
04-15 16:47:31.793: D/OpenGLRenderer(28689): Enabling debug mode 0
04-15 16:47:36.938: D/AndroidRuntime(28689): Shutting down VM
04-15 16:47:36.938: W/dalvikvm(28689): threadid=1: thread exiting with uncaught exception (group=0x40a4c1f8)
04-15 16:47:37.024: E/AndroidRuntime(28689): FATAL EXCEPTION: main
04-15 16:47:37.024: E/AndroidRuntime(28689): java.lang.RuntimeException: Unable to start activity ComponentInfo{app.timer/app.timer.PrefsActivity}: java.lang.ClassCastException: java.lang.Boolean cannot be cast to java.lang.String
04-15 16:47:37.024: E/AndroidRuntime(28689): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1956)
04-15 16:47:37.024: E/AndroidRuntime(28689): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
04-15 16:47:37.024: E/AndroidRuntime(28689): at android.app.ActivityThread.access$600(ActivityThread.java:123)
04-15 16:47:37.024: E/AndroidRuntime(28689): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
04-15 16:47:37.024: E/AndroidRuntime(28689): at android.os.Handler.dispatchMessage(Handler.java:99)
04-15 16:47:37.024: E/AndroidRuntime(28689): at android.os.Looper.loop(Looper.java:137)
04-15 16:47:37.024: E/AndroidRuntime(28689): at android.app.ActivityThread.main(ActivityThread.java:4424)
04-15 16:47:37.024: E/AndroidRuntime(28689): at java.lang.reflect.Method.invokeNative(Native Method)
04-15 16:47:37.024: E/AndroidRuntime(28689): at java.lang.reflect.Method.invoke(Method.java:511)
04-15 16:47:37.024: E/AndroidRuntime(28689): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
04-15 16:47:37.024: E/AndroidRuntime(28689): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
04-15 16:47:37.024: E/AndroidRuntime(28689): at dalvik.system.NativeStart.main(Native Method)
04-15 16:47:37.024: E/AndroidRuntime(28689): Caused by: java.lang.ClassCastException: java.lang.Boolean cannot be cast to java.lang.String
04-15 16:47:37.024: E/AndroidRuntime(28689): at android.app.SharedPreferencesImpl.getString(SharedPreferencesImpl.java:205)
04-15 16:47:37.024: E/AndroidRuntime(28689): at android.preference.Preference.getPersistedString(Preference.java:1396)
04-15 16:47:37.024: E/AndroidRuntime(28689): at app.timer.TimePreference.onSetInitialValue(TimePreference.java:110)
04-15 16:47:37.024: E/AndroidRuntime(28689): at android.preference.Preference.dispatchSetInitialValue(Preference.java:1312)
04-15 16:47:37.024: E/AndroidRuntime(28689): at android.preference.Preference.onAttachedToHierarchy(Preference.java:1124)
04-15 16:47:37.024: E/AndroidRuntime(28689): at android.preference.PreferenceGroup.addPreference(PreferenceGroup.java:156)
04-15 16:47:37.024: E/AndroidRuntime(28689): at android.preference.PreferenceGroup.addItemFromInflater(PreferenceGroup.java:97)
04-15 16:47:37.024: E/AndroidRuntime(28689): at android.preference.PreferenceGroup.addItemFromInflater(PreferenceGroup.java:38)
04-15 16:47:37.024: E/AndroidRuntime(28689): at android.preference.GenericInflater.rInflate(GenericInflater.java:488)
04-15 16:47:37.024: E/AndroidRuntime(28689): at android.preference.GenericInflater.rInflate(GenericInflater.java:493)
04-15 16:47:37.024: E/AndroidRuntime(28689): at android.preference.GenericInflater.inflate(GenericInflater.java:326)
04-15 16:47:37.024: E/AndroidRuntime(28689): at android.preference.GenericInflater.inflate(GenericInflater.java:263)
04-15 16:47:37.024: E/AndroidRuntime(28689): at android.preference.PreferenceManager.inflateFromResource(PreferenceManager.java:269)
04-15 16:47:37.024: E/AndroidRuntime(28689): at android.preference.PreferenceActivity.addPreferencesFromResource(PreferenceActivity.java:1403)
04-15 16:47:37.024: E/AndroidRuntime(28689): at app.timer.PrefsActivity.onCreate(PrefsActivity.java:12)
04-15 16:47:37.024: E/AndroidRuntime(28689): at android.app.Activity.performCreate(Activity.java:4465)
04-15 16:47:37.024: E/AndroidRuntime(28689): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
04-15 16:47:37.024: E/AndroidRuntime(28689): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920)
04-15 16:47:37.024: E/AndroidRuntime(28689): ... 11 more
04-15 16:47:37.137: D/dalvikvm(28689): GC_CONCURRENT freed 230K, 4% free 9362K/9671K, paused 2ms+13ms
我的pref.xml看起来像这样，如果我删除了我的TimePreference
，则有效<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" >
<PreferenceCategory
android:key="time_settings"
android:title="@string/time_settings"
android:summary="@string/time_settings_summary">
<app.timer.TimePreference
android:key="synchronize"
android:title="@string/synchronize"
android:summary="@string/synchronize_summary"
android:icon="@drawable/ic_dialog_time" />
</PreferenceCategory>
<PreferenceCategory
android:key="sound_cat"
android:title="@string/sound_cat"
android:summary="@string/sound_cat_summary">
<CheckBoxPreference
android:key="mute"
android:title="@string/mute"
android:summary="@string/mute_summary"
android:icon="@drawable/ic_audio_vol" />
<ListPreference
android:key="beep_interval"
android:title="@string/beep_interval"
android:summary="@string/beep_interval_summary"
android:entries="@array/beep_interval_options"
android:entryValues="@array/beep_interval_option_values"
android:defaultValue="2"
android:icon="@drawable/ic_audio_alarm" />
</PreferenceCategory>
<PreferenceCategory
android:key="screen"
android:title="@string/screen_cat"
android:summary="@string/screen_cat_summary">
<CheckBoxPreference
android:key="screen_dim"
android:title="@string/screen_dim"
android:summary="@string/screen_dim_summary"
android:icon="@drawable/ic_menu_view" />
<ListPreference
android:key="format"
android:title="@string/format"
android:summary="@string/format_summary"
android:entries="@array/format_options"
android:entryValues="@array/format_option_values"
android:defaultValue="0"
android:icon="@drawable/ic_menu_edit" />
<CheckBoxPreference
android:key="indigo"
android:title="@string/indigo"
android:summary="@string/indigo_summary"
android:icon="@drawable/brightness" />
</PreferenceCategory>
<PreferenceCategory
android:title="@string/about"
android:summary="@string/about_summary" >
<ListPreference
android:key="version_build"
android:enabled="false"
android:title="version 1.01"
android:summary="build 3" />
</PreferenceCategory>
</PreferenceScreen>
这是我的TimePreference类
package app.timer;
import android.content.Context;
import android.content.res.TypedArray;
import android.preference.DialogPreference;
import android.text.format.DateFormat;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.widget.TimePicker;
public class TimePreference extends DialogPreference {
protected int lastHour=0;
protected int lastMinute=0;
protected boolean is24HourFormat;
protected TimePicker picker=null;
protected TextView timeDisplay;
public TimePreference(Context ctxt) {
this(ctxt, null);
}
public TimePreference(Context ctxt, AttributeSet attrs) {
this(ctxt, attrs, 0);
}
public TimePreference(Context ctxt, AttributeSet attrs, int defStyle) {
super(ctxt, attrs, defStyle);
is24HourFormat = DateFormat.is24HourFormat(ctxt);
setPositiveButtonText("Set");
setNegativeButtonText("Cancel");
}
@Override
public String toString() {
if(is24HourFormat) {
return ((lastHour < 10) ? "0" : "")
+ Integer.toString(lastHour)
+ ":" + ((lastMinute < 10) ? "0" : "")
+ Integer.toString(lastMinute);
} else {
int myHour = lastHour % 12;
return ((myHour == 0) ? "12" : ((myHour < 10) ? "0" : "") + Integer.toString(myHour))
+ ":" + ((lastMinute < 10) ? "0" : "")
+ Integer.toString(lastMinute)
+ ((lastHour >= 12) ? " PM" : " AM");
}
}
@Override
protected View onCreateDialogView() {
picker=new TimePicker(getContext().getApplicationContext());
return(picker);
}
@Override
protected void onBindDialogView(View v) {
super.onBindDialogView(v);
picker.setIs24HourView(is24HourFormat);
picker.setCurrentHour(lastHour);
picker.setCurrentMinute(lastMinute);
}
@Override
public void onBindView(View view) {
View widgetLayout;
int childCounter = 0;
do {
widgetLayout = ((ViewGroup) view).getChildAt(childCounter);
childCounter++;
} while (widgetLayout.getId() != android.R.id.widget_frame);
((ViewGroup) widgetLayout).removeAllViews();
timeDisplay = new TextView(widgetLayout.getContext());
timeDisplay.setText(toString());
((ViewGroup) widgetLayout).addView(timeDisplay);
super.onBindView(view);
}
@Override
protected void onDialogClosed(boolean positiveResult) {
super.onDialogClosed(positiveResult);
if (positiveResult) {
picker.clearFocus();
lastHour=picker.getCurrentHour();
lastMinute=picker.getCurrentMinute();
String time=String.valueOf(lastHour)+":"+String.valueOf(lastMinute);
if (callChangeListener(time)) {
persistString(time);
timeDisplay.setText(toString());
}
}
}
@Override
protected Object onGetDefaultValue(TypedArray a, int index) {
return(a.getString(index));
}
@Override
protected void onSetInitialValue(boolean restoreValue, Object defaultValue) {
String time=null;
if (restoreValue) {
if (defaultValue==null) {
time=getPersistedString("00:00");
}
else {
time=getPersistedString(defaultValue.toString());
}
}
else {
if (defaultValue==null) {
time="00:00";
}
else {
time=defaultValue.toString();
}
if (shouldPersist()) {
persistString(time);
}
}
String[] timeParts=time.split(":");
lastHour=Integer.parseInt(timeParts[0]);
lastMinute=Integer.parseInt(timeParts[1]);;
}
}
答案 0 :(得分：1)
java.lang.ClassCastException：java.lang.Boolean无法强制转换为java.lang.String
上面的行标志着你在代码中尝试将布尔变量转换为字符串的某些地方。只需检查一次