java - SharedPreferences 编辑保存

Question

这是我的设置菜单，它是一系列的 9 个图像按钮，可以根据偏好更改图像。当按下图像按钮时，它应该更改首选项的 boolean 值，以便另一个 Activity 可以相应地采取行动。

目前它根据默认值填充图像按钮，但在设置菜单中所做的更改似乎不是永久性的。

public class SettingsActivity extends PreferenceActivity {
    ImageButton[] level = new ImageButton[9];

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_settings);
        PreferenceManager.getDefaultSharedPreferences(this).edit().clear().commit();
        PreferenceManager.setDefaultValues(this, R.xml.preferences, true);

        level[0] = (ImageButton) findViewById(R.id.imageButton);
        level[1] = (ImageButton) findViewById(R.id.imageButton2);
        level[2] = (ImageButton) findViewById(R.id.imageButton3);
        level[3] = (ImageButton) findViewById(R.id.imageButton4);
        level[4] = (ImageButton) findViewById(R.id.imageButton5);
        level[5] = (ImageButton) findViewById(R.id.imageButton6);
        level[6] = (ImageButton) findViewById(R.id.imageButton7);
        level[7] = (ImageButton) findViewById(R.id.imageButton8);
        level[8] = (ImageButton) findViewById(R.id.imageButton9);

        PopulateButtons();

    }

            public void PopulateButtons(){
                SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
                for (int i = 0; i < 9; i++) {
                    String prefKey = String.format("lev%s", i);
                    System.out.println(prefKey);
                    if (preferences.getBoolean(prefKey, false) == true) {
                        level[i].setBackgroundResource(R.mipmap.settings_verbs);
                        level[i].setOnClickListener(mySettingsHandler);
                    } else {
                        level[i].setBackgroundResource(R.mipmap.ic_launcher);
                        level[i].setOnClickListener(mySettingsHandler);
                    }

                }
            }


        View.OnClickListener mySettingsHandler = new View.OnClickListener() {
            public void onClick(View v) {
                Context context = getApplicationContext();
                SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);
                System.out.println("Running populate method");
                for (int i = 0; i < 9; i++) {
                    if (v.getId() == level[i].getId()) {
                        String prefKey = String.format("lev%s", i);
                        if (preferences.getBoolean(prefKey, false) == false) {
                            System.out.println("Yep");
                            SharedPreferences.Editor editor = preferences.edit();
                            editor.putBoolean(prefKey, true);
                            editor.commit();
                            level[i].setBackgroundResource(R.mipmap.settings_verbs);
                        } else {
                            System.out.println("nope");
                            SharedPreferences.Editor editor = preferences.edit();
                            editor.putBoolean(prefKey, false);
                            editor.commit();
                            level[i].setBackgroundResource(R.mipmap.ic_launcher);
                        }
                    }
                }
            }
        };

}

Answer 1

每次调用 onCreate 时，您都在设置默认值。尝试

if (savedInstanceState == null) {
    PreferenceManager.getDefaultSharedPreferences(this).edit().clear().commit();
    PreferenceManager.setDefaultValues(this, R.xml.preferences, true);
}