如何从另一个活动中读取 Sharedpreference 值

Question

我首先做两个活动是 timer.java 活动，这是一个倒计时活动，第二个活动是 SaveRestTime.java 在这个活动中用户在edittext中输入数字值，用户将保存它我现在在这个活动中使用共享首选项我想要哪个如果用户不保存任何值，则保存在 SaveRestTime.java 类中的用户值会自动生成倒计时值，则默认值为 30 秒，请帮助我，我很困惑如何从另一个活动中读取值 这是 timer.java 代码

package com.cinegoes.www.daily10exercise;

import android.app.Activity;
import android.content.Context;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.os.CountDownTimer;
import com.cinegoes.www.daily10exercise.SaveRestTime;
import android.view.View;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.TextView;

import java.util.concurrent.TimeUnit;

import static com.cinegoes.www.daily10exercise.SaveRestTime.mypreference;

/**
 * Created by ever on 7/25/2017.
 */

public class timer extends Activity implements View.OnClickListener {

private CountDownTimer countDownTimer;
private boolean timerStarted = false;
private Button buttonStart;
public TextView textView;
private ProgressBar progressBarCircle;
private final long startTime = 30 * 1000;
private final long interval = 1 * 1000;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.timer);
    buttonStart = (Button) this.findViewById(R.id.button);
    progressBarCircle = (ProgressBar) findViewById(R.id.progressBarCircle);
    buttonStart.setOnClickListener(this);
    textView = (TextView) this.findViewById(R.id.textView);
    countDownTimer = new CountDownTimerActivity(startTime, interval);
    textView.setText(textView.getText() + String.valueOf(startTime/1000));
}

@Override
protected void onStart() {
    super.onStart();
    countDownTimer.start();
    timerStarted = true;
    setProgressBarValues();
}


@Override
public void onClick(View v) {
    finish();
}


public class CountDownTimerActivity extends CountDownTimer {
    public CountDownTimerActivity(long startTime, long interval) {
        super(startTime, interval);
    }

    @Override
    public void onFinish() {
        textView.setText(msTimeFormatter(startTime));
        textView.setText("Time's up!");
        setProgressBarValues();
        finish();
    }


    @Override
    public void onTick(long millisUntilFinished) {
        textView.setText(msTimeFormatter(millisUntilFinished));

        progressBarCircle.setProgress((int) (millisUntilFinished / 1000));
    }
}

private void setProgressBarValues() {

    progressBarCircle.setMax((int) startTime / 1000);
    progressBarCircle.setProgress((int) startTime / 1000);
}
private String msTimeFormatter(long milliSeconds) {

    String ms = String.format("%02d:%02d",
            TimeUnit.MILLISECONDS.toMinutes(milliSeconds) - 
TimeUnit.HOURS.toMinutes(TimeUnit.MILLISECONDS.toHours(milliSeconds)),
            TimeUnit.MILLISECONDS.toSeconds(milliSeconds) - 
TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(milliSeconds)));

    return ms;


}


}

这是我的 SaveRestTime.java 代码

package com.cinegoes.www.daily10exercise;

import android.app.Activity;
import android.content.Context;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.TextView;

public class SaveRestTime extends Activity {
SharedPreferences sharedpreferences;
TextView name;
public static final String mypreference = "mypref";
public static final String Name = "nameKey";


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.saveresttime);

    name = (TextView) findViewById(R.id.etName);
    sharedpreferences = getSharedPreferences(mypreference,
            Context.MODE_PRIVATE);
    if (sharedpreferences.contains(Name)) {
        name.setText(sharedpreferences.getString(Name, ""));
    }

}

public void Save(View view) {
    String n = name.getText().toString();
    SharedPreferences.Editor editor = sharedpreferences.edit();
    editor.putString(Name, n);
    editor.commit();
}



public void Get(View view) {
    name = (TextView) findViewById(R.id.etName);
    sharedpreferences = getSharedPreferences(mypreference, 
Context.MODE_PRIVATE);

    if (sharedpreferences.contains(Name)) 
{name.setText(sharedpreferences.getString(Name, ""));
    }

}

}

Answer 1

SharedPreferences prefs = this.getSharedPreferences("myPref", Context.MODE_PRIVATE);
String lanSettings = prefs.getString("nameKey", null);