Good day, friends. I have a PreferenceActivity, it is filled from XML file. When we press one item, we should launch new act开发者_JS百科ivity. How to do it? What should I write in XML-file or in the Java-class?

Given you are using xml preferences you can add code right into the xml:

<Preference
    android:title="Some Title"
    android:summary="Some Description">

    <intent 
        android:action="android.intent.action.VIEW"
        android:targetPackage="com.package.name"
        android:targetClass="com.package.name.ActivityName"
    />

</Preference>

After you add preferences using

addPreferencesFromResource(R.xml.preferences);

find your preference that you want to set onClick using

findPreference("foo_bar_pref");

and define it by casting like

Preference fooBarPref = (Preference) findPreference("foo_bar_pref");

Then you can easily set its onClick using

fooBarPref.setOnPreferenceClickListener (new OnPreferenceClickListener()){...}

You can start your new Activity (using an Intent) inside that listener.

Gradle Builders, Look Over Here!

If you are using gradle over ant as your build tool, and you declared an applicationId inside android.

[build.gradle]:

android {
    defaultConfig {
        ...
        applicationId "com.overriding.package.name"
    }
    ...
}

This will overwrite whatever value you declared in AndroidManifest.xml's android:package as your app's unique identifier!

[AndroidManifest.xml]

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.my.package">
    <activity android:name=".settings.MyActivity"/>
</manifest>

The <intent> would have to take both package names into account!

<Preference
    android:title="Some Title"
    android:summary="Some Description">

    <intent 
        android:targetPackage="com.overriding.package.name"
        android:targetClass="com.my.package.settings.MyActivity/>
</Preference>

This is nice tutorial for add preferences dynamically...later you have to customized its own way.

In XMl :

<Preference  android:key="key" android:title="See Android Market"></Preference>

In Java class:

Preferences preferences=findPreference("key");
               preferences.setIntent(new Intent(Intent.ACTION_VIEW,Uri.parse("https://market.android.com/")));

OR

import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.preference.CheckBoxPreference;
import android.preference.DialogPreference;
import android.preference.Preference;
import android.preference.PreferenceActivity;
import android.preference.PreferenceCategory;
import android.preference.PreferenceScreen;
import android.widget.LinearLayout;
import android.widget.ListView;

public class SettingsActivity extends PreferenceActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    /* Some initializations */
    LinearLayout layout = new LinearLayout(this);
    layout.setOrientation(LinearLayout.VERTICAL);

    ListView listView = new ListView(this);
    listView.setId(android.R.id.list);
    listView.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT,LinearLayout.LayoutParams.WRAP_CONTENT, 1));
    layout.addView(listView);

    this.setContentView(layout);
    /* Preferences time! (we build the preferences) */
    Preference version = getPreference("My School Manager", "Version 2.0",null);
    Preference author = getPreference("Author", "Balu", null);
    Preference marketLink = getPreference("Android market","View all my apps :)",new Intent(Intent.ACTION_VIEW, Uri.parse("http://market.android.com/")));

    CheckBoxPreference check = new CheckBoxPreference(this);
    check.setTitle("Checkbox");
    check.setSummary("Example of checkbox");
    DialogPreference license = new MyDialogPreference(this, "License","This is the license for...bla bla");

    /* Now we add the preferences to the preference screen */
    PreferenceScreen preferenceScreen = this.getPreferenceManager()
            .createPreferenceScreen(this);
    addPreferenceCategory(preferenceScreen, "Preferences Tutorial",version, author, marketLink, check, license);
    this.setPreferenceScreen(preferenceScreen);
}
private boolean addPreferenceCategory(PreferenceScreen preferenceScreen,
        String titleCategory, Preference... preferences) {
    boolean addPreference = false;
    for (Preference preference : preferences) {
        if (preference != null)
            addPreference = true;
    }
    if (addPreference) {
        PreferenceCategory preferenceCategory = new PreferenceCategory(this);
        preferenceCategory.setTitle(titleCategory);
        preferenceScreen.addPreference(preferenceCategory);
        for (Preference preference : preferences) {
            if (preference != null)
                preferenceCategory.addPreference(preference);
        }
        return true;
    } else
        return false;
}
private Preference getPreference(String title, String summary, Intent intent) {
    Preference pref = new Preference(this);
    pref.setTitle(title);
    pref.setSummary(summary);
    if (intent != null)
        pref.setIntent(intent);
    return pref;
}

public class MyDialogPreference extends DialogPreference {
    public MyDialogPreference(Context context, String title, String text) {
        super(context, null);
        this.setTitle(title);
        this.setDialogMessage(text);
    }
}

}

You have to register an onClickListener to the view you want to launch the activity. Then, inside this method, you just need to invoke the activity with an intent. Something like this:

Intent intent = new Intent(this, ActivityToLaunch.class);

// Start boardgame
startActivity(intent);