在应用程序中保存数据 [英] Saving data in application

问题描述

我已经申请了.这是一个按钮，显示您按下它的时间.每次我杀死"应用程序时，计时器都会再次从 0 开始(自然).我怎样才能让应用程序保存按下按钮的时间，所以当应用程序被杀死，然后你打开它时，计时器就是你停止的时间.我有一些关于这是如何完成的，我认为它与 SharedPreferences 有关.

I have made an application. It's a button that shows the time you have pressed it. Every time I "kill" the application, the timer starts at 0 again (naturally). How can I make the application save the time the button is pressed, so when the application is killed, and then you open it, the timer is at that time you stopped.I have red some about how this is done, and I think it has something to do with SharedPreferences.

我的代码:

public class MainActivity extends ActionBarActivity {

    Button button1;
    Chronometer chromo;
    protected long time;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button button1=(Button)findViewById(R.id.button1);
        chromo=(Chronometer)findViewById(R.id.chromo);

        button1.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                // TODO Auto-generated method stub
                if(event.getAction() == MotionEvent.ACTION_DOWN){
                    chromo.setBase(SystemClock.elapsedRealtime()+time);
                    chromo.start();
                }
                else if( event.getAction() == MotionEvent.ACTION_UP){
                    time =chromo.getBase()-SystemClock.elapsedRealtime();
                    chromo.stop();
                }
                return true;
            }
    });
}}

推荐答案

public class MainActivity extends ActionBarActivity {

    Button button1;
    Chronometer chromo;
    protected long time = 0;
    private SharedPreferences prefs;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button button1=(Button)findViewById(R.id.button1);
        chromo=(Chronometer)findViewById(R.id.chromo);
        prefs = getSharedPreferences("prefs", Context.MODE_PRIVATE);
        long savedValue = prefs.getLong("my_chrono", 0);

        if(savedValue == 0)
            chromo.setBase(SystemClock.elapsedRealtime());
        else
            chromo.setBase(SystemClock.elapsedRealtime() + savedValue);

        button1.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                // TODO Auto-generated method stub
                if(event.getAction() == MotionEvent.ACTION_DOWN){
                    chromo.start();
                }
                else if( event.getAction() == MotionEvent.ACTION_UP){
                    time =chromo.getBase()-SystemClock.elapsedRealtime();
                    chromo.stop();
                    prefs.edit().putLong("my_chrono", time).apply();
                }
                return true;
            }
    });
}}

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要使用共享首选项，请在您的 onCreate 中初始化它

To use the shared preferences, initialize this in you onCreate

SharedPreferences prefs = getSharedPreferences("the_package_of_your_app", Context.MODE_PRIVATE);

然后，尝试获取保存的值

Then, try to get the saved value

int my_saved_value = prefs.getInt("the_package_of_your_app.my_int_1", 0);
if(my_saved_value != 0)
    //your value of your timer was saved, do what's needed with it
else
    //there was no value saved, or the timer was at 0

现在您必须在需要时保存该值(当计时器停止或应用程序关闭时)

Now you have to save that value when needed (when the timer is stopped, or the application is closed)

prefs.edit().putInt("the_package_of_your_app.my_int_1", my_value).apply();

这篇关于在应用程序中保存数据的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！