Question

我从Eclipse和ADT的默认模板SettingsActivity生成了以下代码。我发现它太复杂了。我自己也加了一些。我该如何改进结构？

目前，Activity侦听器和片段侦听器 - ＆gt;更好的方式？
摆脱静态偏好proxyEmail = null; - ＆GT;怎么样？静态可以吗？
如何在onPreferenceChange（）方法（第123行）中调用/使用findPreference（getText（R.string.key_proxy_email））？

重构想法？

package com.xyz.abc;

import java.util.List;

import android.annotation.TargetApi;
import android.content.Context;
import android.content.SharedPreferences;
import android.content.SharedPreferences.OnSharedPreferenceChangeListener;
import android.content.res.Configuration;
import android.os.Build;
import android.os.Bundle;
import android.preference.CheckBoxPreference;
import android.preference.ListPreference;
import android.preference.Preference;
import android.preference.PreferenceActivity;
import android.preference.PreferenceCategory;
import android.preference.PreferenceFragment;
import android.preference.PreferenceManager;
import android.widget.Toast;

public class SettingsActivity extends PreferenceActivity implements OnSharedPreferenceChangeListener {

    private static final boolean ALWAYS_SIMPLE_PREFS = false;

    @Override
    protected void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);

        setupSimplePreferencesScreen();

        // TODO Not used at the moment
        //final SharedPreferences sp = new SecureSharedPreferences(this, this.getSharedPreferences(MY_PREFS_FILE_NAME, Context.MODE_PRIVATE) );

        SharedPreferences settings = getSharedPreferences(Global.PREFERENCES, 0);
        boolean sent = settings.getBoolean(Global.PREF_SETTING_SENT, false);
        if (sent) {
            Toast.makeText(getApplicationContext(), Global.TOAST_MSG_SENT, Toast.LENGTH_LONG);
        } else {
            Toast.makeText(getApplicationContext(), Global.TOAST_MSG_ERROR, Toast.LENGTH_LONG);
        }

    }

    private void setupSimplePreferencesScreen() {
        if (!isSimplePreferences(this)) {
            return;
        }

        addPreferencesFromResource(R.xml.pref_dummy);   // Be able to display first title
        PreferenceCategory fakeHeader = new PreferenceCategory(this);       
        fakeHeader.setTitle(R.string.pref_header_settings);     
        getPreferenceScreen().addPreference(fakeHeader);
        addPreferencesFromResource(R.xml.pref_settings);

        fakeHeader = new PreferenceCategory(this);  
        fakeHeader.setTitle(R.string.pref_header_advanced);
        getPreferenceScreen().addPreference(fakeHeader);
        addPreferencesFromResource(R.xml.pref_advanced);

        fakeHeader = new PreferenceCategory(this);  
        fakeHeader.setTitle(R.string.pref_header_general);
        getPreferenceScreen().addPreference(fakeHeader);
        addPreferencesFromResource(R.xml.pref_general);

        SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(this);
        sp.registerOnSharedPreferenceChangeListener(this);

        toggleProxyEmail(findPreference(getText(R.string.key_via)), findPreference(getText(R.string.key_proxy_email)));
    }

    /** {@inheritDoc} */
    @Override
    public boolean onIsMultiPane() {
        return isXLargeTablet(this) && !isSimplePreferences(this);
    }

    /**
     * Helper method to determine if the device has an extra-large screen. For example, 10" tablets are extra-large.
     */
    private static boolean isXLargeTablet(Context context) {
        return (context.getResources().getConfiguration().screenLayout & Configuration.SCREENLAYOUT_SIZE_MASK) >= Configuration.SCREENLAYOUT_SIZE_XLARGE;
    }

    private static boolean isSimplePreferences(Context context) {
        return ALWAYS_SIMPLE_PREFS || Build.VERSION.SDK_INT < Build.VERSION_CODES.HONEYCOMB || !isXLargeTablet(context);
    }

    /** {@inheritDoc} */
    @Override
    @TargetApi(Build.VERSION_CODES.HONEYCOMB)
    public void onBuildHeaders(List<Header> target) {
        if (!isSimplePreferences(this)) {
            loadHeadersFromResource(R.xml.pref_headers, target);
        }
    }

    private static Preference.OnPreferenceChangeListener bindPrefSummaryToValueListener = new Preference.OnPreferenceChangeListener() {
        @Override
        public boolean onPreferenceChange(Preference preference, Object value) {
            String stringValue = value.toString();

            if (preference instanceof ListPreference) {
                // For list preferences, look up the correct display value in the preference's 'entries' list.
                ListPreference listPreference = (ListPreference) preference;
                int index = listPreference.findIndexOfValue(stringValue);

                // Set the summary to reflect the new value.
                preference.setSummary(index >= 0 ? listPreference.getEntries()[index] : null);

            } else {
                // For all other preferences, set the summary to the value's simple string representation.
                preference.setSummary(stringValue);
            }
            return true;
        } 

    };

    private static Preference.OnPreferenceChangeListener bindPrefKeyToEditTextListener = new Preference.OnPreferenceChangeListener() {
        @Override
        public boolean onPreferenceChange(Preference preference, Object value) {    
            ((CheckBoxPreference) preference).setChecked((Boolean) value);
            toggleProxyEmail(preference, SettingsPreferenceFragment.proxyEmail);

            return true;
        }

    };

    private static void bindPreferenceSummaryToValue(Preference preference) {
        preference.setOnPreferenceChangeListener(bindPrefSummaryToValueListener);

        // Trigger the listener immediately with the preference's current value.
        bindPrefSummaryToValueListener.onPreferenceChange(preference, PreferenceManager.getDefaultSharedPreferences(preference.getContext()).getString(preference.getKey(), ""));
    }

    private static void bindPreferenceKeyToEditText(Preference preference) {
        preference.setOnPreferenceChangeListener(bindPrefKeyToEditTextListener);

        // Trigger the listener immediately with the preference's current value.
        bindPrefKeyToEditTextListener.onPreferenceChange(preference, PreferenceManager.getDefaultSharedPreferences(preference.getContext()).getBoolean(preference.getKey(), false));
    } 


    @TargetApi(Build.VERSION_CODES.HONEYCOMB)
    public static class SettingsPreferenceFragment extends PreferenceFragment {

        static Preference proxyEmail = null;

        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            addPreferencesFromResource(R.xml.pref_settings);

            proxyEmail = findPreference(getText(R.string.key_proxy_email));
            toggleProxyEmail(findPreference(getText(R.string.key_via)), proxyEmail);

            bindPreferenceSummaryToValue(findPreference(getText(R.string.key_dest_email)));
            bindPreferenceKeyToEditText(findPreference(getText(R.string.key_via)));
            bindPreferenceSummaryToValue(findPreference(getText(R.string.key_proxy_email)));
            bindPreferenceSummaryToValue(findPreference(getText(R.string.key_pwd)));
            bindPreferenceSummaryToValue(findPreference(getText(R.string.key_provider)));
        } 
    }

    @TargetApi(Build.VERSION_CODES.HONEYCOMB)
    public static class AdvancedPreferenceFragment extends PreferenceFragment {
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            addPreferencesFromResource(R.xml.pref_advanced);
        }
    }

    @TargetApi(Build.VERSION_CODES.HONEYCOMB)
    public static class GeneralPreferenceFragment extends PreferenceFragment {
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            addPreferencesFromResource(R.xml.pref_general);

            bindPreferenceSummaryToValue(findPreference(getText(R.string.key_help)));
        }
    }

    private static void toggleProxyEmail(Preference prefKey, Preference prefValue) {
        if (prefKey instanceof CheckBoxPreference) {
            if(((CheckBoxPreference) prefKey).isChecked()) {
                prefValue.setEnabled(true);
            } else {
                prefValue.setEnabled(false);
            }
        }
    }

    @Override
    public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {    // Only called in a normal Activity
        if(key.equals(findPreference(getString(R.string.key_via)).getKey())) {
            toggleProxyEmail(findPreference(getText(R.string.key_via)), findPreference(getText(R.string.key_proxy_email)));
        }
    }

}

使用Eclipse ADT中的模板SettingsActivity切换到Tablet支持和片段

0 个答案: