android – addPreferencesFromResource使sharedPreferences不起作用

所以可能是另一个新的问题:)

我有一个Activity,一个AppWidgetProvider和一个PreferenceActivity.在PreferenceActivity中我有一个ListPreference,我用它来定义小部件的文本大小.主活动启动时,sharedPreferences加载时没有任何问题,但是一旦运行PreferenceActivity,我就无法再在主活动中正确检索sharedPreference值.我尝试直接在PreferenceActivity中检索sharedPreference值并发生同样的事情：出于某种原因,当我尝试从sharedPreferences获取值时,我调用addPreferencesFromResource(R.drawable.settings); (在评论’测试1′),它说：

“onStart() 1, size: small” and “Small works!”

即有用.但是当我尝试在资源调用之后检索值时(在评论’测试2′),它说：

“onStart() 2, size: small” and “It doesn’t work …”

即它不起作用.我不知道为什么.显然它获得了sharedPreference的值,因为它表示当前的textWidgetSize在两种情况下都等于“small”,但由于某种原因,它在资源调用之后并不认为“small”=“small”.你们有什么想法吗？

这是PreferenceActivity代码：

package dk.mfoller.android.basicnote;

import android.content.SharedPreferences;
import android.os.Bundle;
import android.preference.PreferenceActivity;
import android.preference.PreferenceManager;
import android.widget.Toast;
import dk.mfoller.android.basicnote.R;

public class BasicNoteSettings extends PreferenceActivity{

    String widgetTextSize = "small";
    boolean widgetLineCounter = true;

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

        // Calls a function to get the preferences
        getPrefs();

        // Test 1
        makeToast("onStart() 1, size: " + widgetTextSize);
        if(widgetTextSize == "small") {
            makeToast("Small works!");
        } else if(widgetTextSize == "medium") {
            makeToast("Medium works!");
        } else if(widgetTextSize == "large") {
            makeToast("Large works!");
        } else {
            makeToast("It doesn't work ...");
        }

        // Gets the preference layout from xml
        addPreferencesFromResource(R.drawable.settings);

        // Calls a function to get the preferences
        getPrefs();

        // Test 2
        makeToast("onStart() 2, size: " + widgetTextSize);
        if(widgetTextSize == "small") {
            makeToast("Small works!");
        } else if(widgetTextSize == "medium") {
            makeToast("Medium works!");
        } else if(widgetTextSize == "large") {
            makeToast("Large works!");
        } else {
            makeToast("It doesn't work ...");
        }

    }

    // A function to get the preferences    
    private void getPrefs() {
        // Gets data from the shared preferences
        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getBaseContext());
        widgetTextSize = prefs.getString("text_size_list", "small");
        widgetLineCounter = prefs.getBoolean("line_counter_cbox", true);
    }

    // A function to display a popup
    private void makeToast(String popup) {
        Toast.makeText(this, popup, Toast.LENGTH_SHORT).show();
    }

}

这是xml文档：

<?xml version="1.0" encoding="utf-8"?>

<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android"
    android:key="basicnote_settings"
    android:title="@string/settings_label">

    <PreferenceCategory android:title="Text size">
        <ListPreference android:key="text_size_list"
        android:title="Widget text size"
        android:summary="@string/text_size_summary"
        android:entries="@array/text_size_options"
        android:entryValues="@array/text_size_values"
        android:defaultValue="small" />
    </PreferenceCategory>

    <PreferenceCategory android:title="Other settings">
        <CheckBoxPreference android:key="line_counter_cbox"
            android:title="Line counter"
            android:summary="@string/hidden_lines_summary"
            android:defaultValue="true" />
    </PreferenceCategory>

</PreferenceScreen>

这是我的资源字符串：

<?xml version="1.0" encoding="utf-8"?>

<!-- Defines various resources -->
<resources>
    <string name="app_name">basicNote</string>
    <string name="note_hint">Tap to add some notes ...</string>
    <string name="fake_load">Loading notes ...</string>

    <string name="settings_label">basicNote settings</string>

    <string name="text_size_summary">Set the size of the widget text</string>
    <string-array name="text_size_options">
        <item>Small (12sp)</item>
        <item>Medium (13sp)</item>
        <item>Large (15sp)</item>
    </string-array>
    <string-array name="text_size_values">
        <item>small</item>
        <item>medium</item>
        <item>large</item>
    </string-array>

    <string name="hidden_lines_summary">Show/hide the number of lines not shown in the widget</string>
</resources>

解决方法:

您在String对象上使用==.请改用.equals(yourString).

标签：preferenceactivity,android,sharedpreferences
来源： https://codeday.me/bug/20190902/1792941.html