问题
One question: I have a EditTextPreference to let the user type in a default path for the app.
How can I manage that the new value is to be seen in the preferencefragment I use?
After the user clicked ok in the preference window to complete the new settings I want to write the new path as a summary below the title.
I have tried already experiencing with the onSharedPreferenceChanged but it did not work. I do not know how to get access to the edit field from the popup window where the users text is in.
Hope to find some help Andreas!
Edit: Here is the source code for the whole PreferenceFragment I used and modified with the suggestions of Rustam. Unfortunately it does not work.
package com.example.wbsettings;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.preference.EditTextPreference;
import android.preference.Preference;
import android.preference.PreferenceFragment;
public class PreferenceFrag extends PreferenceFragment
implements SharedPreferences.OnSharedPreferenceChangeListener{
public static final String KEYVAL = "startpath";
SharedPreferences sp;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Load the preferences from an XML resource
addPreferencesFromResource(R.xml.preferences);
EditTextPreference prefUrl = (EditTextPreference) findPreference(KEYVAL);
prefUrl.getEditText().setHint("default path");
//>> Here the app crashed when I debug it
------------------------------------
prefUrl.setSummary(sp.getString(KEYVAL, ""));
}//onCreate
public void onSharedPreferenceChanged(SharedPreferences sharedPreferences,String key) {
Preference pref = findPreference(key);
if (pref instanceof EditTextPreference) {
EditTextPreference etp = (EditTextPreference) pref;
pref.setSummary(etp.getText());
}
}//onSharedPreferenceChanged
}
What I also do not understand in your example: Where is the preferences to register with the OnSharedPreferenceChangeListener? I mean as of now I never reach the onSharedPreferenceChanged procedure because of the crash. But when I make the statement a comment and the app is running and finished I have never been stopped at the breakpoint I set within the onSharedPreferenceChanged procedure.
Another question: What is the best practice here to answer a comment if the answer becomes too long for another comment? I tried to open an answer to my own question. But a pop up informed me that this is not the way it should be. So what to do?
Regards Andreas!
回答1:
your menu_setting.xml :
<menu xmlns:android="http://schemas.android.com/apk/res/android" >
<item
android:id="@+id/menu_settings"
android:orderInCategory="100"
android:showAsAction="never"
android:title="@string/menu_settings"
android:icon="@android:drawable/ic_menu_preferences"/>
</menu>
your preference.xml :
<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" >
<EditTextPreference
android:dialogTitle="Enter path"
android:key="prefPath"
android:summary=""
android:title="Path Setting" />
</PreferenceScreen>
your PreferenceFrag should look like this :
import android.content.SharedPreferences;
import android.os.Bundle;
import android.preference.EditTextPreference;
import android.preference.Preference;
import android.preference.PreferenceFragment;
public class PreferenceFrag extends PreferenceFragment
implements SharedPreferences.OnSharedPreferenceChangeListener{
public static final String KEYVAL = "prefPath";
SharedPreferences sp;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Load the preferences from an XML resource
addPreferencesFromResource(R.xml.preference);
EditTextPreference prefPath = (EditTextPreference) findPreference(KEYVAL);
prefPath.getEditText().setHint("sdcard/path");
// Here the app crashed when I debug it
SharedPreferences sp = getPreferenceScreen().getSharedPreferences();
prefPath.setSummary(sp.getString(KEYVAL, ""));
}//onCreate
@Override
public void onResume() {
super.onResume();
// Set up a listener whenever a key changes
getPreferenceScreen().getSharedPreferences()
.registerOnSharedPreferenceChangeListener(this);
}
@Override
public void onPause() {
super.onPause();
// Unregister the listener whenever a key changes
getPreferenceScreen().getSharedPreferences()
.unregisterOnSharedPreferenceChangeListener(this);
}
public void onSharedPreferenceChanged(SharedPreferences sharedPreferences,String key) {
Preference pref = findPreference(key);
if (pref instanceof EditTextPreference) {
EditTextPreference etp = (EditTextPreference) pref;
pref.setSummary(etp.getText());
}
}//onSharedPreferenceChanged
}
your PreferenceActivity :
import android.app.Activity;
import android.os.Bundle;
public class PreferenceActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
getFragmentManager().beginTransaction().replace(android.R.id.content,
new PreferenceFrag()).commit();
}
}
your MainActivity :
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;
public class MainActivity extends Activity {
private TextView textview;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textview=(TextView)findViewById(R.id.textview);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_setting, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.menu_settings:
Intent i = new Intent(this, PreferenceActivity.class);
startActivity(i);
break;
}
return true;
}
}
finally AndroidManifest.xml:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.preferencetest"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="18" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.preferencetest.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name="com.example.preferencetest.PreferenceActivity"/>
</application>
</manifest>
来源：https://stackoverflow.com/questions/25865048/how-to-get-the-sumary-from-preferences