在Android应用程序的屏幕旋转保存变量
问题描述：
当我在我的android应用程序中旋转屏幕时，变量（犯规，目标等）被重置。我希望它们不会在屏幕旋转时重置。我能怎么做？ 我知道问题与活动的生命周期有关，但我无法解决它，因为我从一个非常快的时间（2个月）发展而来。 这是MainActivity.java在Android应用程序的屏幕旋转保存变量
package com.marconota.serieasoccerscorekeeper;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
import org.apache.commons.lang3.StringUtils;
import java.lang.String;
public class MainActivity extends AppCompatActivity {
String scorerNames = "Marcatori: ";
String lastScorer = "";
int goalsForTeamA = 0;
int goalsForTeamB = 0;
int shotsForTeamA = 0;
int shotsForTeamB = 0;
int foulsForTeamA = 0;
int foulsForTeamB = 0;
int cornersForTeamA = 0;
int cornersForTeamB = 0;
int yellowCardsForTeamA = 0;
int yellowCardsForTeamB = 0;
int redCardsForTeamA = 0;
int redCardsForTeamB = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
// Displays scorers list
public void displayScorers(String score) {
TextView scoreView = (TextView) findViewById(R.id.listaMarcatori);
scoreView.setText(String.valueOf(score));
}
/**
* Displays score for Team A.
*/
public void displayGoalsForTeamA(int score) {
TextView scoreView = (TextView) findViewById(R.id.showGoalsForTeamA);
scoreView.setText(String.valueOf(score));
}
/**
* Displays score for Team B.
*/
public void displayGoalsForTeamB(int score) {
TextView scoreView = (TextView) findViewById(R.id.showGoalsForTeamB);
scoreView.setText(String.valueOf(score));
}
/**
* Displays shots for Team A.
*/
public void displayShotsForTeamA(int score) {
TextView scoreView = (TextView) findViewById(R.id.showShotsForTeamA);
scoreView.setText(String.valueOf(score));
}
/**
* Displays shots for Team B.
*/
public void displayShotsForTeamB(int score) {
TextView scoreView = (TextView) findViewById(R.id.showShotsForTeamB);
scoreView.setText(String.valueOf(score));
}
/**
* Displays corners for Team A.
*/
public void displayCornersForTeamA(int score) {
TextView scoreView = (TextView) findViewById(R.id.showCornersForTeamA);
scoreView.setText(String.valueOf(score));
}
/**
* Displays corners for Team B.
*/
public void displayCornersForTeamB(int score) {
TextView scoreView = (TextView) findViewById(R.id.showCornersForTeamB);
scoreView.setText(String.valueOf(score));
}
/**
* Displays fouls for Team A.
*/
public void displayFoulsForTeamA(int score) {
TextView scoreView = (TextView) findViewById(R.id.showFoulsForTeamA);
scoreView.setText(String.valueOf(score));
}
/**
* Displays fouls for Team B.
*/
public void displayFoulsForTeamB(int score) {
TextView scoreView = (TextView) findViewById(R.id.showFoulsForTeamB);
scoreView.setText(String.valueOf(score));
}
/**
* Displays yellow cards for Team A.
*/
public void displayYellowCardsForTeamA(int score) {
TextView scoreView = (TextView) findViewById(R.id.showYellowCardsForTeamA);
scoreView.setText(String.valueOf(score));
}
/**
* Displays yellow cards for Team B.
*/
public void displayYellowCardsForTeamB(int score) {
TextView scoreView = (TextView) findViewById(R.id.showYellowCardsForTeamB);
scoreView.setText(String.valueOf(score));
}
/**
* Displays red cards for Team A.
*/
public void displayRedCardsForTeamA(int score) {
TextView scoreView = (TextView) findViewById(R.id.showRedCardsForTeamA);
scoreView.setText(String.valueOf(score));
}
/**
* Displays red cards for Team B.
*/
public void displayRedCardsForTeamB(int score) {
TextView scoreView = (TextView) findViewById(R.id.showRedCardsForTeamB);
scoreView.setText(String.valueOf(score));
}
// Adds goal for team A
public void addOneGoalForTeamA(View view) {
goalsForTeamA = goalsForTeamA + 1;
displayGoalsForTeamA(goalsForTeamA);
}
// Adds goal for team B
public void addOneGoalForTeamB(View view) {
goalsForTeamB = goalsForTeamB + 1;
displayGoalsForTeamB(goalsForTeamB);
}
// Subtracts goal for team A and prevents stat provides negative number
public void subtractOneGoalForTeamA(View view) {
if (goalsForTeamA>0)
{goalsForTeamA = goalsForTeamA - 1;
displayGoalsForTeamA(goalsForTeamA);
}
else
{goalsForTeamA = 0;
displayGoalsForTeamA(goalsForTeamA);
}
}
// Subtracts goal for team B and prevents stat provides negative number
public void subtractOneGoalForTeamB(View view) {
if (goalsForTeamB>0)
{goalsForTeamB = goalsForTeamB - 1;
displayGoalsForTeamB(goalsForTeamB);
}
else
{goalsForTeamB = 0;
displayGoalsForTeamB(goalsForTeamB);
}
}
// Adds shot for team A
public void addOneShotForTeamA(View view) {
shotsForTeamA = shotsForTeamA + 1;
displayShotsForTeamA(shotsForTeamA);
}
// Adds shot for team B
public void addOneShotForTeamB(View view) {
shotsForTeamB = shotsForTeamB + 1;
displayShotsForTeamB(shotsForTeamB);
}
// Subtracts shot for team A and prevents stat provides negative number
public void subtractOneShotForTeamA(View view) {
if (shotsForTeamA>0)
{shotsForTeamA = shotsForTeamA - 1;
displayShotsForTeamA(shotsForTeamA);
}
else
{shotsForTeamA = 0;
displayShotsForTeamA(shotsForTeamA);
}
}
// Subtracts shot for team B and prevents stat provides negative number
public void subtractOneShotForTeamB(View view) {
if (shotsForTeamB>0)
{shotsForTeamB = shotsForTeamB - 1;
displayShotsForTeamB(shotsForTeamB);
}
else
{shotsForTeamB = 0;
displayShotsForTeamB(shotsForTeamB);
}
}
// Adds corner for team A
public void addOneCornerForTeamA(View view) {
cornersForTeamA = cornersForTeamA + 1;
displayCornersForTeamA(cornersForTeamA);
}
// Adds corner for team B
public void addOneCornerForTeamB(View view) {
cornersForTeamB = cornersForTeamB + 1;
displayCornersForTeamB(cornersForTeamB);
}
// Subtracts corner for team A and prevents stat provides negative number
public void subtractOneCornerForTeamA(View view) {
if (cornersForTeamA>0)
{cornersForTeamA = cornersForTeamA - 1;
displayCornersForTeamA(cornersForTeamA);
}
else
{cornersForTeamA = 0;
displayCornersForTeamA(cornersForTeamA);
}
}
// Subtracts corner for team B and prevents stat provides negative number
public void subtractOneCornerForTeamB(View view) {
if (cornersForTeamB>0)
{cornersForTeamB = cornersForTeamB - 1;
displayCornersForTeamB(cornersForTeamB);
}
else
{cornersForTeamB = 0;
displayCornersForTeamB(cornersForTeamB);
}
}
// Adds foul for team A
public void addOneFoulForTeamA(View view) {
foulsForTeamA = foulsForTeamA + 1;
displayFoulsForTeamA(foulsForTeamA);
}
// Adds foul for team B
public void addOneFoulForTeamB(View view) {
foulsForTeamB = foulsForTeamB + 1;
displayFoulsForTeamB(foulsForTeamB);
}
// Subtracts foul for team A and prevents stat provides negative number
public void subtractOneFoulForTeamA(View view) {
if (foulsForTeamA>0)
{foulsForTeamA = foulsForTeamA - 1;
displayFoulsForTeamA(foulsForTeamA);
}
else
{foulsForTeamA = 0;
displayFoulsForTeamA(foulsForTeamA);
}
}
// Subtracts foul for team B and prevents stat provides negative number
public void subtractOneFoulForTeamB(View view) {
if (foulsForTeamB>0)
{foulsForTeamB = foulsForTeamB - 1;
displayFoulsForTeamB(foulsForTeamB);
}
else
{foulsForTeamB = 0;
displayFoulsForTeamB(foulsForTeamB);
}
}
// Adds yellow card for team A
public void addOneYellowCardForTeamA(View view) {
yellowCardsForTeamA = yellowCardsForTeamA + 1;
displayYellowCardsForTeamA(yellowCardsForTeamA);
}
// Adds yellow card for team B
public void addOneYellowCardForTeamB(View view) {
yellowCardsForTeamB = yellowCardsForTeamB + 1;
displayYellowCardsForTeamB(yellowCardsForTeamB);
}
// Subtracts yellow card for team A and prevents stat provides negative number
public void subtractOneYellowCardForTeamA(View view) {
if (yellowCardsForTeamA>0)
{yellowCardsForTeamA = yellowCardsForTeamA - 1;
displayYellowCardsForTeamA(yellowCardsForTeamA);
}
else
{yellowCardsForTeamA = 0;
displayYellowCardsForTeamA(yellowCardsForTeamA);
}
}
// Subtracts yellow card for team B and prevents stat provides negative number
public void subtractOneYellowCardForTeamB(View view) {
if (yellowCardsForTeamB>0)
{yellowCardsForTeamB = yellowCardsForTeamB - 1;
displayYellowCardsForTeamB(yellowCardsForTeamB);
}
else
{yellowCardsForTeamB = 0;
displayYellowCardsForTeamB(yellowCardsForTeamB);
}
}
// Adds red card for team A
public void addOneRedCardForTeamA(View view) {
redCardsForTeamA = redCardsForTeamA + 1;
displayRedCardsForTeamA(redCardsForTeamA);
}
// Adds red card for team B
public void addOneRedCardForTeamB(View view) {
redCardsForTeamB = redCardsForTeamB + 1;
displayRedCardsForTeamB(redCardsForTeamB);
}
// Subtracts red card for team A and prevents stat provides negative number
public void subtractOneRedCardForTeamA(View view) {
if (redCardsForTeamA>0)
{redCardsForTeamA = redCardsForTeamA - 1;
displayRedCardsForTeamA(redCardsForTeamA);
}
else
{redCardsForTeamA = 0;
displayRedCardsForTeamA(redCardsForTeamA);
}
}
// Subtracts red card for team B and prevents stat provides negative number
public void subtractOneRedCardForTeamB(View view) {
if (redCardsForTeamB>0)
{redCardsForTeamB = redCardsForTeamB - 1;
displayRedCardsForTeamB(redCardsForTeamB);
}
else
{redCardsForTeamB = 0;
displayRedCardsForTeamB(redCardsForTeamB);
}
}
// Resets match stats
public void resetMatchStats(View view) {
scorerNames = "Marcatori: ";
displayScorers(scorerNames);
lastScorer = "";
goalsForTeamA = 0;
displayGoalsForTeamA(goalsForTeamA);
goalsForTeamB = 0;
displayGoalsForTeamB(goalsForTeamB);
shotsForTeamA = 0;
displayShotsForTeamA(shotsForTeamA);
shotsForTeamB = 0;
displayShotsForTeamB(shotsForTeamB);
foulsForTeamA = 0;
displayFoulsForTeamA(foulsForTeamA);
foulsForTeamB = 0;
displayFoulsForTeamB(foulsForTeamB);
cornersForTeamA = 0;
displayCornersForTeamA(cornersForTeamA);
cornersForTeamB = 0;
displayCornersForTeamB(cornersForTeamB);
yellowCardsForTeamA = 0;
displayYellowCardsForTeamA(yellowCardsForTeamA);
yellowCardsForTeamB = 0;
displayYellowCardsForTeamB(yellowCardsForTeamB);
redCardsForTeamA = 0;
displayRedCardsForTeamA(redCardsForTeamA);
redCardsForTeamB = 0;
displayRedCardsForTeamB(redCardsForTeamB);
}
//Adds last scorer in editText to scorers list and displays the updated scorers list
//If the add scorer field is empty, it doesn't update variable lastScorer.
//Else it takes the value from add scorer field, assign it to variable lastScorer, then it displays updated scorers
public void addScorer(View view) {
EditText addScorer = (EditText) findViewById(R.id.addScorerField);
String lastScorerPrep = addScorer.getText().toString();
if (StringUtils.isEmpty(lastScorerPrep))
{
}
else {
lastScorer = lastScorerPrep;
scorerNames = scorerNames + lastScorer + ", ";
displayScorers(scorerNames);
}
}
//Deletes last scorer from scorers list
public void deleteLastScorer(View view) {
scorerNames = scorerNames.replaceFirst((lastScorer + ", "), "");
displayScorers(scorerNames);
}
}
谢谢你对我的帮助。
答
我解决了，通过将变量放入方法onSaveInstanceState的包savedInstanceState中，然后再从方法onResumeInstanceState中的包中获取变量来保存变量。这是Java代码：
// Saves variables in Bundle savedInstanceState
@Override
public void onSaveInstanceState(Bundle savedInstanceState) {
super.onSaveInstanceState(savedInstanceState);
savedInstanceState.putInt("GoalsForTeamA", goalsForTeamA);
savedInstanceState.putInt("GoalsForTeamB", goalsForTeamB);
savedInstanceState.putInt("ShotsForTeamA", shotsForTeamA);
savedInstanceState.putInt("ShotsForTeamB", shotsForTeamB);
savedInstanceState.putInt("CornersForTeamA", cornersForTeamA);
savedInstanceState.putInt("CornersForTeamB", cornersForTeamB);
savedInstanceState.putInt("FoulsForTeamA", foulsForTeamA);
savedInstanceState.putInt("FoulsForTeamB", foulsForTeamB);
savedInstanceState.putInt("YellowCardsForTeamA", yellowCardsForTeamA);
savedInstanceState.putInt("YellowCardsForTeamB", yellowCardsForTeamB);
savedInstanceState.putInt("RedCardsForTeamA", redCardsForTeamA);
savedInstanceState.putInt("RedCardsForTeamB", redCardsForTeamB);
savedInstanceState.putString("ScorerNames",scorerNames);
savedInstanceState.putString("LastScorer", lastScorer);
}
// Gets variables from Bundle savedInstanceState and displays them again.
@Override
public void onRestoreInstanceState(Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
goalsForTeamA = savedInstanceState.getInt("GoalsForTeamA");
goalsForTeamB = savedInstanceState.getInt("GoalsForTeamB");
shotsForTeamA = savedInstanceState.getInt("ShotsForTeamA");
shotsForTeamB = savedInstanceState.getInt("ShotsForTeamB");
foulsForTeamA = savedInstanceState.getInt("FoulsForTeamA");
foulsForTeamB = savedInstanceState.getInt("FoulsForTeamB");
cornersForTeamA = savedInstanceState.getInt("CornersForTeamA");
cornersForTeamB = savedInstanceState.getInt("CornersForTeamB");
yellowCardsForTeamA = savedInstanceState.getInt("YellowCardsForTeamA");
yellowCardsForTeamB = savedInstanceState.getInt("YellowCardsForTeamB");
redCardsForTeamA = savedInstanceState.getInt("RedCardsForTeamA");
redCardsForTeamB = savedInstanceState.getInt("RedCardsForTeamB");
scorerNames = savedInstanceState.getString("ScorerNames");
lastScorer = savedInstanceState.getString("LastScorer");
displayGoalsForTeamA(goalsForTeamA);
displayGoalsForTeamB(goalsForTeamB);
displayShotsForTeamA(shotsForTeamA);
displayShotsForTeamB(shotsForTeamB);
displayFoulsForTeamA(foulsForTeamA);
displayFoulsForTeamB(foulsForTeamB);
displayCornersForTeamA(cornersForTeamA);
displayCornersForTeamB(cornersForTeamB);
displayYellowCardsForTeamA(yellowCardsForTeamA);
displayYellowCardsForTeamB(yellowCardsForTeamB);
displayRedCardsForTeamA(redCardsForTeamA);
displayRedCardsForTeamB(redCardsForTeamB);
displayScorers(scorerNames);
}
https://developer.android.com/guide/components/activities/activity-lifecycle.html#saras使用'onSaveInstanceState' –
您也可以到这里看看：HTTP：/ /stackoverflow.com/questions/151777/saving-android-activity-state-using-save-instance-state – vadber
在我看来，你至少已经在搜索你的问题 – peter