java - 如何在 Android 中使用共享首选项？

Question

我正在 Android 中使用 SQLite 实现切换按钮。我想将切换按钮值保存在共享首选项中，并将共享首选项值存储在 SQLite 中。当我运行应用程序时，我收到切换按钮的空指针异常。

我不知道如何在共享首选项中存储 boolean 值。这是我的代码和日志目录。

这是我的切换按钮代码

toggleButton_Addto_Contacts = (ToggleButton) findViewById(R.id.toggleButton_Add_To_Contacts);

toggleButton_Addto_Contacts.setOnCheckedChangeListener(new OnCheckedChangeListener() {

    @Override
    public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
        // TODO Auto-generated method stub


        if(isChecked)
        {
            System.out.println("Toggle Button Is On");

            SharedPreferences.Editor editor = preferences.edit();
            editor.putBoolean("YES",  true); // value to store
            strBooleanValue=sharedPref.getBoolean("YES",true);
            strToggleVlaue=String.valueOf(strBooleanValue);
            System.out.println("Toggle Button Value Is =" + strToggleVlaue);
            editor.commit();

        }
        else
        {

                System.out.println("Toggle Button Is Off");
                SharedPreferences.Editor editor = preferences.edit();
                editor.putBoolean("NO",  false); // value to store
                strBooleanValue=sharedPref.getBoolean("NO", false);
                strToggleVlaue=String.valueOf(strBooleanValue);
                System.out.println("Toggle Button Value Is =" + strToggleVlaue);
                editor.commit();

        }
    }
});



11-28 15:13:26.054: E/AndroidRuntime(707): FATAL EXCEPTION: main
11-28 15:13:26.054: E/AndroidRuntime(707): java.lang.NullPointerException
11-28 15:13:26.054: E/AndroidRuntime(707):  at com.lead_management_project.New_Lead_Activity5$5.onCheckedChanged(New_Lead_Activity5.java:172)
11-28 15:13:26.054: E/AndroidRuntime(707):  at android.widget.CompoundButton.setChecked(CompoundButton.java:124)
11-28 15:13:26.054: E/AndroidRuntime(707):  at android.widget.ToggleButton.setChecked(ToggleButton.java:69)
11-28 15:13:26.054: E/AndroidRuntime(707):  at android.widget.CompoundButton.toggle(CompoundButton.java:86)
11-28 15:13:26.054: E/AndroidRuntime(707):  at android.widget.CompoundButton.performClick(CompoundButton.java:98)
11-28 15:13:26.054: E/AndroidRuntime(707):  at android.view.View$PerformClick.run(View.java:9080)
11-28 15:13:26.054: E/AndroidRuntime(707):  at android.os.Handler.handleCallback(Handler.java:587)
11-28 15:13:26.054: E/AndroidRuntime(707):  at android.os.Handler.dispatchMessage(Handler.java:92)
11-28 15:13:26.054: E/AndroidRuntime(707):  at android.os.Looper.loop(Looper.java:123)
11-28 15:13:26.054: E/AndroidRuntime(707):  at android.app.ActivityThread.main(ActivityThread.java:3683)
11-28 15:13:26.054: E/AndroidRuntime(707):  at java.lang.reflect.Method.invokeNative(Native Method)
11-28 15:13:26.054: E/AndroidRuntime(707):  at java.lang.reflect.Method.invoke(Method.java:507)
11-28 15:13:26.054: E/AndroidRuntime(707):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
11-28 15:13:26.054: E/AndroidRuntime(707):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
11-28 15:13:26.054: E/AndroidRuntime(707):  at dalvik.system.NativeStart.main(Native Method)

Answer 1

尝试如下更改，

    if(isChecked)
            {
                System.out.println("Toggle Button Is On");

                SharedPreferences.Editor editor = preferences.edit();
                editor.putBoolean("YES",  true); // value to store
                editor.commit();
                strBooleanValue=preferences.getBoolean("YES",true);
                strToggleVlaue=String.valueOf(strBooleanValue);
                System.out.println("Toggle Button Value Is =" + strToggleVlaue);


            }
 else
        {

                System.out.println("Toggle Button Is Off");
                SharedPreferences.Editor editor = preferences.edit();
                editor.putBoolean("NO",  false); // value to store
                editor.commit();
                strBooleanValue=preferences.getBoolean("NO", false);
                strToggleVlaue=String.valueOf(strBooleanValue);
                System.out.println("Toggle Button Value Is =" + strToggleVlaue);


        }