如何从设置活动修改MainActivity上的数据

Question

我尝试过许多其他线程和文章，但就是找不到合适的东西。所以我有一个MainActivity和一个SettingsActivity，它们都是java类。在我的主要活动中，有一个按钮在按下时会使计数增加+1，并在TextView上显示，它还使设备在每次增加/每次按下按钮时都会振动。我想在设置活动中设置一个开关首选项，如果保持off/false，则关闭振动开启按钮，如果保持on/true，则打开振动开启按钮。我不知道如何从SettingsActivity中检索SwitchPreferenceCompat(ON或OFF(的状态，并在MainActivity中使用它，所以如果用户在设置活动中关闭开关，振动应该在按下MainActivity中的按钮时停止。我已经在MainActivity中使用了共享首选项来保存应用程序关闭时的当前计数/编号，并在重新打开时从相同计数恢复。

主要活动

package com.saad.tapcounter;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import androidx.constraintlayout.widget.ConstraintLayout;
import androidx.preference.PreferenceManager;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.graphics.Color;
import android.os.Bundle;
import android.os.Vibrator;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.Switch;
import android.widget.TextView;
import android.widget.Toast;
import com.google.android.gms.ads.AdRequest;
import com.google.android.gms.ads.AdView;
import com.google.android.gms.ads.MobileAds;
public class MainActivity extends AppCompatActivity {
private AdView mAdView ;
int Start;
TextView txt;
Button btnU,btnT,btnR;
Switch sw,sw2;
private ConstraintLayout Clayout;
Vibrator vibe;
Boolean switchPref;
SharedPreferences sharedPreferences;
private static long back_pressed;
private Vibrator Vibrator;
//Double Tap Exit
@Override
public void onBackPressed()
{
if (back_pressed + 2000 > System.currentTimeMillis()) super.onBackPressed();
else Toast.makeText(getBaseContext(), "Press once again to exit!", Toast.LENGTH_SHORT).show();
back_pressed = System.currentTimeMillis();
}

//Inflater for Menu
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.menu,menu);
return true;
}
//Menu
@Override
public boolean onOptionsItemSelected(@NonNull MenuItem item) {
switch(item.getItemId()){
case R.id.menui1:
startActivity(new Intent(this, SettingsActivity.class));
return true;

default:
return super.onOptionsItemSelected(item);
}
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

Toolbar toolbar = findViewById(R.id.toolbarid);
setSupportActionBar(toolbar);

MobileAds.initialize(this, "-APPID-");
mAdView = findViewById(R.id.adView);
AdRequest adRequest = new AdRequest.Builder().build();
mAdView.loadAd(adRequest);
vibe =(Vibrator)getSystemService(VIBRATOR_SERVICE);
Clayout = findViewById(R.id.MainLayout);
btnT =  findViewById(R.id.tapbtn);
btnR =  findViewById(R.id.resetbtn);
btnU =  findViewById(R.id.undobtn);
sw = findViewById(R.id.swch);
sw2 = findViewById(R.id.darkswch);
txt =  findViewById(R.id.txtv);
txt.setTextColor(Color.BLACK);
sharedPreferences = getSharedPreferences("0",MODE_PRIVATE);
loadData();
setData();
incrementbtn();
undobtn();
resetbtn();
switchbtn();
themeswitch();

}
public void loadData(){
sharedPreferences = getSharedPreferences("0",MODE_PRIVATE);
}
private void setData(){
Start = sharedPreferences.getInt("0",0);
if(Start==0){
txt.setText("0");
}
else{
txt.setText(Integer.toString(Start));
}
}
public void incrementbtn(){
btnT.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
incvibe();
if (Start != 0) {
Start = sharedPreferences.getInt("0", 0);
Start += 1;
txt.setText(Integer.toString(Start));
txtresize();
} else {
Start += 1;
txt.setText(Integer.toString(Start));
}
sharedPreferences.edit().putInt("0", Start).apply();
}
});
}
public void undobtn(){
btnU.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
undovibe();
if (Start != 0) {
Start = sharedPreferences.getInt("0", 0);
Start -= 1;
txt.setText(Integer.toString(Start));
}
else{
return;
}
sharedPreferences.edit().putInt("0", Start).apply();
}
});
}
public void resetbtn(){
btnR.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
resetvibe();
Start = 0;
txt.setText(Integer.toString(Start));
sharedPreferences.edit().putInt("0", Start).apply();
}
});
}
public void switchbtn(){
sw.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if(sw.isChecked()) {
btnR.setEnabled(false);
btnT.setEnabled(false);
btnU.setEnabled(false);
txt.setTextColor(Color.RED);
}
else{
btnR.setEnabled(true);
btnT.setEnabled(true);
btnU.setEnabled(true);
if(sw2.isChecked()){
txt.setTextColor(Color.WHITE);
}
else{
txt.setTextColor(Color.BLACK);
}
}
}
});
}
public void themeswitch(){
sw2.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if(sw2.isChecked()){
Clayout.setBackgroundColor(Color.DKGRAY);
if(sw.isChecked()){
txt.setTextColor(Color.RED);
}
else{
txt.setTextColor(Color.WHITE);
}
}
else{
Clayout.setBackgroundColor(Color.WHITE);
if(sw.isChecked()){
txt.setTextColor(Color.RED);
}
else{
txt.setTextColor(Color.BLACK);
}
}
}
});
}
public void txtresize(){
if(Start > 1000 && Start < 10000){
txt.setTextSize(80);
}
else if (Start > 10000 && Start < 100000){
txt.setTextSize(60);
}
else if (Start > 100000){
txt.setTextSize(40);
}
else{
return;
}
}
StringBuilder info = new StringBuilder();

public void undovibe(){
vibe.vibrate(100);
}
public void resetvibe(){
vibe.vibrate(150);
}
public void incvibe(){
vibe.vibrate(40);
}
}//Real one

设置活动(从NEW>设置活动创建(我确实在这里自己尝试了一些东西，但它破坏了我的应用程序。

package com.saad.tapcounter;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.widget.Toast;
import androidx.appcompat.app.ActionBar;
import androidx.appcompat.app.AppCompatActivity;
import androidx.preference.PreferenceFragmentCompat;
import androidx.preference.PreferenceManager;
public class SettingsActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.settings_activity);
getSupportFragmentManager()
.beginTransaction()
.replace(R.id.settings, new SettingsFragment())
.commit();
ActionBar actionBar = getSupportActionBar();
if (actionBar != null) {
actionBar.setDisplayHomeAsUpEnabled(true);
}
}
public static class SettingsFragment extends PreferenceFragmentCompat {
@Override
public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
setPreferencesFromResource(R.xml.root_preferences, rootKey);
}
}

}

root_preference.xml

<PreferenceScreen xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:android="http://schemas.android.com/apk/res/android">
<PreferenceCategory app:title="Settings"
app:iconSpaceReserved="false">
<SwitchPreferenceCompat
app:key="Switchsett1"
app:title="Vibration"
app:summaryOff="Turn Vibration On"
app:summaryOn="Turn Vibration Off"
app:iconSpaceReserved="false"
app:defaultValue="true"
/>
<SwitchPreferenceCompat
app:key="Switchset2"
app:iconSpaceReserved="false"
app:summaryOff="@string/attachment_summary_off"
app:summaryOn="@string/attachment_summary_on"
app:title="@string/attachment_title" />
</PreferenceCategory>
</PreferenceScreen>

Answer 1

我不知道如何从设置活动检索开关状态(ON或OFF(

要从共享首选项中获取SwitchPreferenceCompat的值，则需要将其作为Boolean进行检索

现在，您的第一个SwitchPreferenceCompat的密钥是Switchsett1，所以要检索这个值：

public class MainActivity extends AppCompatActivity {
Boolean switchPref;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
....
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
switchPref = prefs.getBoolean("Switchsett1", false);
Toast.makeText(this, String.valueOf(switchPref), Toast.LENGTH_SHORT).show(); // shows true if the SwitchPreferenceCompat is ON, and false if OFF.

现在，如果SwitchPreferenceCompat为ON，则上面脚本中的Toast显示true，如果为OFF，则显示false

您可以对Switchset2SwitchPreferenceCompat执行相同操作