Android example source code file (LaunchingPreferences.java)

This example Android source code file (LaunchingPreferences.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

activity, android, button, content, intent, launchingpreferences, linearlayout, onclicklistener, os, override, preference, request_code_preferences, sharedpreferences, textview, ui, widget

The LaunchingPreferences.java Android example source code

/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.android.apis.app;

import com.example.android.apis.R;

import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.LinearLayout.LayoutParams;

/**
 * Demonstrates launching a PreferenceActivity and grabbing a value it saved.
 */
public class LaunchingPreferences extends Activity implements OnClickListener {

    private static final int REQUEST_CODE_PREFERENCES = 1;
    
    private TextView mCounterText;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        /*
         * If this were my app's main activity, I would load the default values
         * so they're set even if the user does not go into the preferences
         * screen. Another good place to call this method would be from a
         * subclass of Application, so your default values would be loaded
         * regardless of entry into your application (for example, a service or
         * activity).
         */  
        PreferenceManager.setDefaultValues(this, R.xml.advanced_preferences, false);
        
        // Simple layout
        LinearLayout layout = new LinearLayout(this);
        layout.setOrientation(LinearLayout.VERTICAL);
        setContentView(layout);
        
        // Create a simple button that will launch the preferences
        Button launchPreferences = new Button(this);
        launchPreferences.setText(getString(R.string.launch_preference_activity));
        launchPreferences.setOnClickListener(this);
        layout.addView(launchPreferences, new LayoutParams(LayoutParams.FILL_PARENT,
                LayoutParams.WRAP_CONTENT));
        
        mCounterText = new TextView(this);
        layout.addView(mCounterText, new LayoutParams(LayoutParams.FILL_PARENT,
                LayoutParams.WRAP_CONTENT));
        
        updateCounterText();
    }

    public void onClick(View v) {
        
        // When the button is clicked, launch an activity through this intent
        Intent launchPreferencesIntent = new Intent().setClass(this, AdvancedPreferences.class);
        
        // Make it a subactivity so we know when it returns
        startActivityForResult(launchPreferencesIntent, REQUEST_CODE_PREFERENCES);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        
        // The preferences returned if the request code is what we had given
        // earlier in startSubActivity
        if (requestCode == REQUEST_CODE_PREFERENCES) {
            // Read a sample value they have set
            updateCounterText();
        }
    }

    private void updateCounterText() {
        // Since we're in the same package, we can use this context to get
        // the default shared preferences
        SharedPreferences sharedPref = PreferenceManager.getDefaultSharedPreferences(this);
        final int counter = sharedPref.getInt(AdvancedPreferences.KEY_MY_PREFERENCE, 0);
        mCounterText.setText(getString(R.string.counter_value_is) + " " + counter);
    }
}