java - 我在 SharedPreferences 保存 int 时遇到问题

Question

package com.carterharrison.taptap;

import android.app.Activity;
import android.content.Context;
import android.content.SharedPreferences;
import android.media.MediaPlayer;
import android.os.Vibrator;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.TextView;


public class MainActivity extends ActionBarActivity {
    SharedPreferences SP;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        SP = getSharedPreferences("points", Context.MODE_PRIVATE);


    }




        public int x = SP.getInt("points", -1);



    public void val1(View v){

        x = (x+1);
        con();

    }

    public void val2(View v){

        x = (x+2);
        con();
    }

    public void val3(View v){

        x = (x+5);
        con();
        }

    public void val4(View v){

        x = (x+10);
    con();

}

public void val5(View v){

    x = (x+25);
    con();

}

public void val6(View v){

    x = (x+50);
    con();

}

public void con(){
    SharedPreferences.Editor editor  = SP.edit();

    if (x > 1000) {
        ImageView img5=(ImageView)findViewById(R.id.imageView5);
        img5.setVisibility(View.VISIBLE);}
    if (x > 625) {
        ImageView img4=(ImageView)findViewById(R.id.imageView4);
        img4.setVisibility(View.VISIBLE);}
    if (x > 300) {
        ImageView img3=(ImageView)findViewById(R.id.imageView3);
        img3.setVisibility(View.VISIBLE);}
    if (x > 100) {
        ImageView img2=(ImageView)findViewById(R.id.imageView2);
        img2.setVisibility(View.VISIBLE);}
    if (x > 30) {
        ImageView img=(ImageView)findViewById(R.id.ImageView);
        img.setVisibility(View.VISIBLE);}

    TextView tv = (TextView)findViewById(R.id.val);
    tv.setText("" + x);


    editor.putInt("score", x);
    editor.apply();

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}

}

我正在尝试保存 int x 的值。我的应用程序在启动时崩溃，有人可以帮助我吗，我对 java 和 SharedPreferences 很陌生，谢谢。我可能做错了，我需要帮助保存 x 的值。

Answer 1

在SharedPReference中设置int值。

public void SaveInt(String key, int value){
    SharedPreferences sharedPreferences = getSharedPreferences("points", Activity.MODE_PRIVATE)
    SharedPreferences.Editor editor = sharedPreferences.edit();
    editor.putInt(key, value);
    editor.commit();
} 

从SharedPreference获取Int值

public void LoadInt(String key){
    SharedPreferences sharedPreferences = getSharedPreferences("points", Activity.MODE_PRIVATE)
    int savedValue = sharedPreferences.getInt(key, 0);
}

编辑:

每当您想要在共享首选项中保存int值时，只需调用方法即可如下所示:

SaveInt("my_int", 5);

每当你想检索相同 int 的值时:

int mScore = LoadInt("my_int");

希望对您有帮助。