Android How to - Update Preferences

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The following code shows how to Update Preferences.

Example

Register permission

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.java2s.myapplication3.app" >
    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="18" />
    <uses-permission android:name="com.java2s.myapplication3.app.READ_PREFERENCES" />
    <uses-permission android:name="com.java2s.myapplication3.app.WRITE_PREFERENCES" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="java2s.com"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.java2s.myapplication3.app.MainActivity"
            android:label="java2s.com"
            >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

Main layout xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
    <Button
        android:id="@+id/button_settings"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Show Settings"
        android:onClick="onSettingsClick" />
    <CheckBox
        android:id="@+id/checkbox_enable"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/button_settings"
        android:text="Set Enable Setting"/>
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:orientation="vertical">
        <TextView
            android:id="@+id/value_enabled"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />
        <TextView
            android:id="@+id/value_name"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />
        <TextView
            android:id="@+id/value_selection"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />
    </LinearLayout>
</RelativeLayout>

Java code

package com.java2s.myapplication3.app;
//w  w w . j  a va 2 s .c  o m
import android.app.Activity;
import android.content.ActivityNotFoundException;
import android.content.ContentValues;
import android.content.Intent;
import android.database.ContentObserver;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.os.Handler;
import android.provider.Settings;
import android.view.View;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.CompoundButton.OnCheckedChangeListener;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity implements OnCheckedChangeListener {

    public static final String SETTINGS_ACTION = "com.java2s.sharepreferences.ACTION_SETTINGS";
    public static final Uri SETTINGS_CONTENT_URI =
            Uri.parse("content://com.java2s.sharepreferences.settingsprovider/settings");
    public static class SettingsColumns {
        public static final String _ID = Settings.NameValueTable._ID;
        public static final String NAME = Settings.NameValueTable.NAME;
        public static final String VALUE = Settings.NameValueTable.VALUE;
    }

    TextView mEnabled, mName, mSelection;
    CheckBox mToggle;

    private ContentObserver mObserver = new ContentObserver(new Handler()) {
        public void onChange(boolean selfChange) {
            updatePreferences();
        }
    };

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mEnabled = (TextView) findViewById(R.id.value_enabled);
        mName = (TextView) findViewById(R.id.value_name);
        mSelection = (TextView) findViewById(R.id.value_selection);
        mToggle = (CheckBox) findViewById(R.id.checkbox_enable);
        mToggle.setOnCheckedChangeListener(this);
    }

    @Override
    protected void onResume() {
        super.onResume();
        updatePreferences();
        getContentResolver().registerContentObserver(SETTINGS_CONTENT_URI, false, mObserver);
    }

    @Override
    public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
        ContentValues cv = new ContentValues(2);
        cv.put(SettingsColumns.NAME, "preferenceEnabled");
        cv.put(SettingsColumns.VALUE, isChecked);
        getContentResolver().update(SETTINGS_CONTENT_URI, cv, null, null);
    }

    public void onSettingsClick(View v) {
        try {
            Intent intent = new Intent(SETTINGS_ACTION);
            startActivity(intent);
        } catch (ActivityNotFoundException e) {
            Toast.makeText(this,
                    "You do not have the Settings App installed.",
                    Toast.LENGTH_SHORT).show();
        }
    }

    private void updatePreferences() {
        Cursor c = getContentResolver().query(SETTINGS_CONTENT_URI,
                new String[] {SettingsColumns.NAME, SettingsColumns.VALUE},
                null, null, null);
        if (c == null) {
            return;
        }

        while (c.moveToNext()) {
            String key = c.getString(0);
            if ("preferenceEnabled".equals(key)) {
                mEnabled.setText( String.format("Enabled Setting = %s", c.getString(1)) );
                mToggle.setChecked( Boolean.parseBoolean(c.getString(1)) );
            } else if ("preferenceName".equals(key)) {
                mName.setText( String.format("User Name Setting = %s", c.getString(1)) );
            } else if ("preferenceSelection".equals(key)) {
                mSelection.setText( String.format("Selection Setting = %s", c.getString(1)) );
            }
        }

        c.close();
    }

}

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