MainActivity.java
package com.jamesvuong.footballscorekeeper;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
final int TOUCHDOWN_POINTS = 6;
final int FIELD_GOAL_POINTS = 3;
final int EXTRA_POINT_1_POINT = 1;
final int EXTRA_POINT_2_POINTS = 2;
final int SAFETY_POINTS = 2;
String score_a , score_b;
String TEXT_A , TEXT_B;
int team_a_score;
int team_b_score;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState); // Always call the superclass first
// Check whether we're recreating a previously destroyed instance
if (savedInstanceState != null) {
// Restore value of members from saved state
team_a_score = savedInstanceState.getInt(TEXT_A);
team_b_score = savedInstanceState.getInt(TEXT_B);
}
else {
// Probably initialize members with default values for a new instance
team_a_score = 0;
team_b_score = 0;
}
setContentView(R.layout.activity_main);
displayTeamAScore(team_a_score);
displayTeamBScore(team_b_score);
}
@Override
public void onSaveInstanceState(Bundle savedInstanceState) {
// Save the user's current game state
savedInstanceState.putInt(TEXT_A,team_a_score);
savedInstanceState.putInt(TEXT_B, team_b_score);
// Always call the superclass so it can save the view hierarchy state
super.onSaveInstanceState(savedInstanceState);
}
public void onRestoreInstanceState(Bundle savedInstanceState) {
// Always call the superclass so it can restore the view hierarchy
super.onRestoreInstanceState(savedInstanceState);
// Restore state members from saved instance
team_a_score = savedInstanceState.getInt(TEXT_A);
team_b_score = savedInstanceState.getInt(TEXT_B);
}
/**
* Update Scores
*/
public void resetScores(View v) {
team_a_score = 0;
team_b_score = 0;
displayTeamAScore(team_a_score);
displayTeamBScore(team_b_score);
}
public void updateTeamScore(View v) {
switch(v.getId()) {
case R.id.team_a_touchdown:
team_a_score += TOUCHDOWN_POINTS;
break;
case R.id.team_a_field_goal:
team_a_score += FIELD_GOAL_POINTS;
break;
case R.id.team_a_extra_point_1:
team_a_score += EXTRA_POINT_1_POINT;
break;
case R.id.team_a_extra_point_2:
team_a_score += EXTRA_POINT_2_POINTS;
break;
case R.id.team_a_safety:
team_a_score += SAFETY_POINTS;
break;
case R.id.team_b_touchdown:
team_b_score += TOUCHDOWN_POINTS;
break;
case R.id.team_b_field_goal:
team_b_score += FIELD_GOAL_POINTS;
break;
case R.id.team_b_extra_point_1:
team_b_score += EXTRA_POINT_1_POINT;
break;
case R.id.team_b_extra_point_2:
team_b_score += EXTRA_POINT_2_POINTS;
break;
case R.id.team_b_safety:
team_b_score += SAFETY_POINTS;
break;
default:
break;
}
displayTeamAScore(team_a_score);
displayTeamBScore(team_b_score);
}
/**
* Display Scores
*/
public void displayTeamAScore(int score) {
TextView scoreView = (TextView) findViewById(R.id.team_a_score);
scoreView.setText(String.valueOf(score));
}
public void displayTeamBScore(int score) {
TextView scoreView = (TextView) findViewById(R.id.team_b_score);
scoreView.setText(String.valueOf(score));
}
}
activity_main.xml中
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="10dp"
tools:context="com.jamesvuong.footballscorekeeper.MainActivity">
<LinearLayout
android:id="@+id/score_container"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="2"
android:layout_marginBottom="10dp"
android:orientation="horizontal">
<LinearLayout
android:id="@+id/team_a_score_container"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="6"
android:orientation="vertical">
<TextView
android:id="@+id/team_a_label"
android:text="Team A"
style="@style/TeamLabelStyle"/>
<TextView
android:id="@+id/team_a_score"
android:text="0"
android:saveEnabled="true"
style="@style/ScoreTextStyle"/>
</LinearLayout>
<LinearLayout
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1">
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="-"
android:gravity="center"
android:textStyle="bold"
android:textSize="30sp"/>
</LinearLayout>
<LinearLayout
android:id="@+id/team_b_score_container"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="6"
android:orientation="vertical">
<TextView
android:id="@+id/team_b_label"
android:text="Team B"
style="@style/TeamLabelStyle"/>
<TextView
android:id="@+id/team_b_score"
android:text="0"
android:saveEnabled="true"
style="@style/ScoreTextStyle"/>
</LinearLayout>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="@android:color/darker_gray"
android:layout_marginBottom="10dp">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
<LinearLayout
android:id="@+id/scoring_buttons_container"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="4"
android:layout_gravity="center"
android:orientation="vertical">
<LinearLayout
android:id="@+id/touchdown_container"
style="@style/ScoreTypeButtonContainerStyle">
<Button
android:id="@+id/team_a_touchdown"
style="@style/ScoreButtonStyle"
android:text="+6"
android:onClick="updateTeamScore"/>
<TextView
android:text="Touchdown"
style="@style/ScoreTypeLabelStyle"/>
<Button
android:id="@+id/team_b_touchdown"
style="@style/ScoreButtonStyle"
android:text="+6"
android:onClick="updateTeamScore"/>
</LinearLayout>
<LinearLayout
android:id="@+id/field_goal_container"
style="@style/ScoreTypeButtonContainerStyle">
<Button
android:id="@+id/team_a_field_goal"
style="@style/ScoreButtonStyle"
android:text="+3"
android:onClick="updateTeamScore"/>
<TextView
android:text="Field Goal"
style="@style/ScoreTypeLabelStyle"/>
<Button
android:id="@+id/team_b_field_goal"
style="@style/ScoreButtonStyle"
android:text="+3"
android:onClick="updateTeamScore"/>
</LinearLayout>
<LinearLayout
android:id="@+id/extra_point_container"
style="@style/ScoreTypeButtonContainerStyle">
<Button
android:id="@+id/team_a_extra_point_1"
style="@style/ScoreButtonStyle"
android:text="+1"
android:onClick="updateTeamScore"/>
<Button
android:id="@+id/team_a_extra_point_2"
style="@style/ScoreButtonStyle"
android:text="+2"
android:onClick="updateTeamScore"/>
<TextView
style="@style/ScoreTypeLabelStyle"
android:text="Extra Point" />
<Button
android:id="@+id/team_b_extra_point_1"
style="@style/ScoreButtonStyle"
android:text="+1"
android:onClick="updateTeamScore"/>
<Button
android:id="@+id/team_b_extra_point_2"
style="@style/ScoreButtonStyle"
android:text="+2"
android:onClick="updateTeamScore"/>
</LinearLayout>
<LinearLayout
android:id="@+id/safety_container"
style="@style/ScoreTypeButtonContainerStyle">
<Button
android:id="@+id/team_a_safety"
style="@style/ScoreButtonStyle"
android:text="+2"
android:onClick="updateTeamScore"/>
<TextView
style="@style/ScoreTypeLabelStyle"
android:text="Safety"/>
<Button
android:id="@+id/team_b_safety"
style="@style/ScoreButtonStyle"
android:text="+2"
android:onClick="updateTeamScore"/>
</LinearLayout>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="@android:color/darker_gray"
android:layout_marginBottom="10dp">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:orientation="vertical">
<Button
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#333333"
android:onClick="resetScores"
android:text="Reset"
android:textColor="#FFFFFF" />
</LinearLayout>
</LinearLayout>
我想保存一些值，比如团队的得分，这样即使在应用程序被杀死（不在后台运行）之后，分数也会保存，并且可以在用户再次打开app时保留。尝试使用＆＃39; savedInstanceState＆＃39;但它不起作用。请帮忙。我是android开发的初学者。
答案 0 :(得分：0)
savedInstanceState用于在屏幕旋转期间保存应用的当前状态，而不是永久保存数据。 SharedPreferences正是您要找的。这是一个例子：
SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
// save
sharedPreferences.edit()
.putString("key1", "value")
.putInt("key2", 10)
.apply();
// retrieve
String stringValue = sharedPreferences.getString("key1", null);
int intValue = sharedPreferences.getInt("key2", -1);
// null and -1 are default values if not found
答案 1 :(得分：0)
如果您的应用尚未被杀死，那么您可以使用saveInstanceState / Application类存储值，否则U必须使用共享首选项或Sqlite /其他ORM。