Android:当应用程序关闭时保存实例状态
可能重复:
如何保存Android应用程序的状态?
我是Java和Android的新手,并构建了一些小型项目来学习。 我做了一个钱跟踪应用程序,允许用户输入值,它只是继续减去它。 一切工作正常,但我想要的值保存或缓存时,应用程序关闭并重新打开。 在阅读中,我发现OnPause可能会诀窍,但仍不能100%理解它。
任何人都可以推荐如何做到这一点,以及如何适用于我的代码?
非常感谢你的帮助!!
package ps.age.sl;
import java.text.NumberFormat;
import java.util.Locale;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.TextView;
public class MoneyTrackerActivity extends Activity {
/** Called when the activity is first created. */
ImageButton subtract;
EditText startingmoney,submoney, endmoney, tracker;
Locale currentLocale = Locale.getDefault();
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// startingmoney = (EditText) findViewById (R.id.firstmoney);
// submoney = (EditText) findViewById (R.id.submoney);
// subtract = (ImageButton) findViewById (R.id.subbutton);
// endmoney = (EditText) findViewById (R.id.endtv);
// tracker = (EditText) findViewById (R.id.trackertv);
startingmoney.setText("");
submoney.setText("");
endmoney.setText("");
subtract.setOnClickListener(new View.OnClickListener() {
double currentValue=0;
double startValue=0;
public void onClick(View v) throws NumberFormatException {
if (v == subtract)
{
NumberFormat currencyFormatter;
currencyFormatter = NumberFormat.getCurrencyInstance(currentLocale);
String totalString;
String x = startingmoney.getText().toString();
String y = submoney.getText().toString ();
double total;
double xm = 0.00;
double ym =0.00;
try
{
xm = Double.parseDouble(x);
}
catch(NumberFormatException n)
{
xm = 0.00;
}
try
{
ym = Double.parseDouble(y);
}
catch(NumberFormatException n)
{
ym = 0.00;
}
if(startValue!=xm){
startValue=xm;
currentValue=xm;
}
currentValue = currentValue -ym;
totalString = currencyFormatter.format(currentValue);
endmoney.setText(totalString);
tracker.setText("you have entered " + totalString +"n" + tracker.getText().toString());
}
}
});
}
}
请使用SharedPreferences
将数据存储在私人应用程序存储中。 在像以下这样的onPause方法中实现SharedPrefernces
:
@Override
protected void onPause()
{
super.onPause();
// Store values between instances here
SharedPreferences preferences = getSharedPreferences("sharedPrefs", 0);
SharedPreferences.Editor editor = preferences.edit();
editor.putString("CLASSLABEL", this.getLocalClassName()); // value to store
editor.putString("STRINGLABEL",String1 );
editor.putString("STRINGLABEL1",String2);
// Commit to storage
editor.commit();
}
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