How to add a button to a PreferenceScreen?

问题:

I'm quite new to Android Development and just came across Preferences. I found PreferenceScreens and wanted to create a login functionality with it. The only problem I have it that I don't know hot i could add a "Login" button to the PreferenceScreen. Here's how my Preference View looks like:

<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
...
    <PreferenceScreen android:title="@string/login" android:key="Login">
        <EditTextPreference android:persistent="true" android:title="@string/username" android:key="Username"></EditTextPreference>
        <EditTextPreference android:title="@string/password" android:persistent="true" android:password="true" android:key="Password"></EditTextPreference>
    </PreferenceScreen>
...
</PreferenceScreen>

The Button should be right under the two ExitTextPreferences.

Is there a simple solution for this problem? The one solution i found was not working because i use sub Preference Screens.

Update:

I figured out that i can add buttons this way:

<PreferenceScreen android:title="@string/login" android:key="Login">
        <EditTextPreference android:persistent="true" android:title="@string/username" android:key="Username"></EditTextPreference>
        <EditTextPreference android:title="@string/password" android:persistent="true" android:password="true" android:key="Password"></EditTextPreference>
        <Preference android:layout="@layout/loginButtons" android:key="loginButtons"></Preference>
</PreferenceScreen>

and the layout file (loginButtons.xml) looks that way:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_height="wrap_content"
    android:layout_width="fill_parent"
    android:weightSum="10" 
    android:baselineAligned="false" android:orientation="horizontal">
    <Button android:text="Login" android:layout_width="fill_parent"
        android:layout_weight="5" android:layout_height="wrap_content"
        android:id="@+id/loginButton" android:layout_gravity="left"></Button>
    <Button android:text="Password?" android:layout_width="fill_parent"
        android:layout_weight="5" android:layout_height="wrap_content"
        android:id="@+id/forgottenPasswordButton"></Button>
</LinearLayout>

So now the buttons appear but I can't access them in code. I tried it with findViewById() but this is returning null. Any ideas how i could access these buttons?

回答1:

For the xml:

<Preference android:title="Acts like a button"
                android:key="@string/myCoolButton"
                android:summary="This is a cool button"/>

Then for the java in your onCreate()

Preference button = findPreference(getString(R.string.myCoolButton));
button.setOnPreferenceClickListener(new Preference.OnPreferenceClickListener() {
                @Override
                public boolean onPreferenceClick(Preference preference) {   
                    //code for what you want it to do   
                    return true;
                }
            });

This will appear like a normal Preference, with just a title and a summary, so it will look like it belongs.

Edit: I changed to using @string/myCoolButton and getString(R.string.myCoolButton) because it's best to use resources for compiler assistance, language translation, and ease of String changes.

回答2:

I wanted to add an Exit link to the preferences and was able to modify Jakar's code to make it work like this:

<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" >   
   <PreferenceCategory android:title="Settings">
       <Preference android:title="Click to exit" android:key="exitlink"/>       
   </PreferenceCategory>    
</PreferenceScreen>

Originally the 'Preference' was a 'EditTextPreference' which I hand edited.

Then in the class:

public class MyPreferences extends PreferenceActivity {
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    addPreferencesFromResource(R.xml.mypreferences);

    Preference button = (Preference)getPreferenceManager().findPreference("exitlink");      
    if (button != null) {
        button.setOnPreferenceClickListener(new Preference.OnPreferenceClickListener() {
            @Override
            public boolean onPreferenceClick(Preference arg0) {
                finish();   
                return true;
            }
        });     
    }
}
}

回答3:

I suppouse its too late. This is what i have done for a Button Preference.

The preference in preference.xml file in xml folder

....
    <Preference
        android:key="resetBD"
        android:title="@string/ajustes_almacenamiento"
        android:summary="@string/ajustes_almacenamiento_desc"
        android:widgetLayout="@layout/pref_reset_bd_button" 
    ></Preference>
  ...

and pref_reset_bd_button.xml in layout folder

 <?xml version="1.0" encoding="utf-8"?>
   <Button
       xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/resetButton" 
        android:text="@string/ajustes_almacenamiento_bt" 
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="resetearBD">

   </Button>

回答4:

Add

setContentView(R.layout.buttonLayout);

Below

addPreferencesFromResource(R.xml.yourPreference);

buttonLayout:

<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

<RelativeLayout
        android:id="@+id/top_control_bar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
</RelativeLayout>

<LinearLayout
        android:id="@+id/bottom_control_bar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true">

    <Button
            android:id="@+id/button"
            android:layout_width="match_parent"
            android:layout_height="70dp"
            android:text="@string/saveAlarm"/>
</LinearLayout>

<ListView
        android:id="@android:id/list"
        android:layout_width="fill_parent"
        android:layout_height="0dip"
        android:layout_above="@id/bottom_control_bar"
        android:layout_below="@id/top_control_bar"
        android:choiceMode="multipleChoice">
</ListView>

Access Button by:

Button button = (Button) findViewById(R.id.button);
button.setOnClickListener(new OnClickListener() {
    @Override
    public void onClick(View v) {
        //Your event
    }
});

You can get the button on top or on bottom of the screen by putting the button in RelativeLayout:

• top_control_bar
• bottom_control_bar

bottom_control_bar

This worked for me. I hope I can help someone with this piece of code.

回答5:

I don't think there is an easy way to just add a Button to a preference screen. Preferences are limited to:

EditTextPreference
ListPreference
RingtonePreference
CheckboxPreference

While using a preference screen, you are limited to the use of these options, and there are no single "button-preference" which could be easily used for your need.

I've been looking for similar functionality, with adding buttons to the preference screen, but it seems like you need to build your own screen for this, managing the change to preferences in your own implementation.

回答6:

You can do it like this to access the button!

 View footerView = ((LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE)).inflate(R.layout.layoutButtons, null, false);

Don't forget to add android:id to the LinearLayout that contains the button in layoutButtons.xml, i.e. android:id="@+id/mylayout"

 LinearLayout mLayout = (LinearLayout) footerView.findViewById(R.id.mylayout);
 Button login = (Button) footerView.findViewById(R.id.loginButton);
 login.setOnClickListener(this);
 ListView lv = (ListView) findViewById(android.R.id.list);
 lv.addFooterView(footerView);

 // Lines 2 and 3 can be used in the same way for a second Button!

回答7:

try android:onClick="myMethod" works like a charm for simple onclick events

回答8:

You can also customise the layout of a Preference by overriding Preference.onCreateView(parent). The example below uses an anonymous inner class to make red preferences.

    screen.addPreference(
        new Preference(context) {
            @Override
            protected View onCreateView(ViewGroup parent) {
                View view = super.onCreateView(parent);
                view.setBackgroundColor(Color.RED);
                return view;
            }
        });

You could use this technique to add a button to the default view.