我使用来自here.的Kevin Remo的回答创建了我自己的自定义PreferenceActivity。此代码没有onPreferenceClickListener，因此我添加了onResume我的活动。它在API 9上运行良好，但在API 19上失败。
以下是我的活动代码。
import android.content.Context;
import android.os.Bundle;
import android.preference.CheckBoxPreference;
import android.preference.Preference;
import android.preference.Preference.OnPreferenceClickListener;
import android.util.AttributeSet;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Toast;
public class SettingsActivity extends CompatiblePreferenceActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
setPrefs(R.xml.user_settings);
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(View parent, String name, Context context,
AttributeSet attrs) {
// TODO Auto-generated method stub
return super.onCreateView(parent, name, context, attrs);
}
@Override
protected void onPause() {
// TODO Auto-generated method stub
super.onPause();
}
@Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
Preference logout = (Preference) findPreference("preflogout");
logout.setOnPreferenceClickListener(new OnPreferenceClickListener() {
public boolean onPreferenceClick(Preference preference) {
Toast.makeText(getApplicationContext(), preference.getKey(),
Toast.LENGTH_LONG).show();
return false;
// open browser or intent here
}
});
CheckBoxPreference notification = (CheckBoxPreference) findPreference("prefpushnotification");
notification
.setOnPreferenceClickListener(new OnPreferenceClickListener() {
public boolean onPreferenceClick(Preference preference) {
CheckBoxPreference notification1 = (CheckBoxPreference) preference;
if (notification1.isChecked()) {
notification1.setSummary("Notification is on");
} else {
notification1.setSummary("Notification is off");
}
return false;
// open browser or intent here
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.user_setting, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
在onResume中我使用的是findPreferences（），它在API 19上提供NPE，但适用于API9。
这是我使用的自定义首选项活动类，它支持2x到4x版本，如回答链接所述。
import android.annotation.TargetApi;
import android.os.Bundle;
import android.preference.Preference;
import android.preference.PreferenceActivity;
import android.preference.PreferenceFragment;
import android.preference.PreferenceScreen;
public class CompatiblePreferenceActivity extends PreferenceActivity {
private int prefs = 0;
// Get/Set
public void setPrefs(int prefs) {
this.prefs = prefs;
}
// Exception
protected static class PrefsNotSetException extends RuntimeException {
private static final long serialVersionUID = 1L;
PrefsNotSetException() {
super("\"prefs\" should be set to a valid preference resource ID.");
}
}
// Creation
@Override
protected void onCreate(final Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (prefs == 0)
throw new PrefsNotSetException();
else
try {
getClass().getMethod("getFragmentManager");
AddResourceApi11AndGreater();
} catch (NoSuchMethodException e) { // Api < 11
AddResourceApiLessThan11();
}
}
@SuppressWarnings("deprecation")
protected void AddResourceApiLessThan11() {
addPreferencesFromResource(prefs);
}
@TargetApi(11)
protected void AddResourceApi11AndGreater() {
PF.prefs = prefs;
getFragmentManager().beginTransaction()
.replace(android.R.id.content, new PF()).commit();
}
@TargetApi(11)
public static class PF extends PreferenceFragment {
private static int prefs;
@Override
public void onCreate(final Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(prefs);
}
}
// Sub-screen background glitch fix
@SuppressWarnings("deprecation")
@Override
public boolean onPreferenceTreeClick(PreferenceScreen preferenceScreen,
Preference preference) {
super.onPreferenceTreeClick(preferenceScreen, preference);
if (preference != null)
if (preference instanceof PreferenceScreen)
if (((PreferenceScreen) preference).getDialog() != null)
((PreferenceScreen) preference)
.getDialog()
.getWindow()
.getDecorView()
.setBackgroundDrawable(
this.getWindow().getDecorView()
.getBackground().getConstantState()
.newDrawable());
return false;
}
}
堆栈追踪：
02-13 19:54:08.222: E/AndroidRuntime(4282): java.lang.RuntimeException: Unable to resume activity {com.buzzreel/com.buzzreel.SettingsActivity}: java.lang.NullPointerException
02-13 19:54:08.222: E/AndroidRuntime(4282): at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2774)
02-13 19:54:08.222: E/AndroidRuntime(4282): at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:2803)
02-13 19:54:08.222: E/AndroidRuntime(4282): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2238)
02-13 19:54:08.222: E/AndroidRuntime(4282): at android.app.ActivityThread.access$800(ActivityThread.java:135)
02-13 19:54:08.222: E/AndroidRuntime(4282): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
02-13 19:54:08.222: E/AndroidRuntime(4282): at android.os.Handler.dispatchMessage(Handler.java:102)
02-13 19:54:08.222: E/AndroidRuntime(4282): at android.os.Looper.loop(Looper.java:136)
02-13 19:54:08.222: E/AndroidRuntime(4282): at android.app.ActivityThread.main(ActivityThread.java:5001)
02-13 19:54:08.222: E/AndroidRuntime(4282): at java.lang.reflect.Method.invokeNative(Native Method)
02-13 19:54:08.222: E/AndroidRuntime(4282): at java.lang.reflect.Method.invoke(Method.java:515)
02-13 19:54:08.222: E/AndroidRuntime(4282): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
02-13 19:54:08.222: E/AndroidRuntime(4282): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
02-13 19:54:08.222: E/AndroidRuntime(4282): at dalvik.system.NativeStart.main(Native Method)
02-13 19:54:08.222: E/AndroidRuntime(4282): Caused by: java.lang.NullPointerException
02-13 19:54:08.222: E/AndroidRuntime(4282): at com.buzzreel.SettingsActivity.onResume(SettingsActivity.java:42)
02-13 19:54:08.222: E/AndroidRuntime(4282): at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1192)
02-13 19:54:08.222: E/AndroidRuntime(4282): at android.app.Activity.performResume(Activity.java:5310)