小编dor*_*159的帖子

当我启动我的应用程序时它只是崩溃并给我这个错误代码:

尝试在空对象引用上调用虚方法'android.content.SharedPreferences android.content.Context.getSharedPreferences(java.lang.String,int)'

这对我来说都很新鲜,请帮帮我.

这是我的主要活动

package com.awplicity.testappshared;

import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity {
    SharedPreferences sharedPreferences = getSharedPreferences("", Context.MODE_PRIVATE);
    SharedPreferences.Editor editor = sharedPreferences.edit();
    Button button1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    private void onClick(View v) {
        switch(v.getId()) {
            case R.id.nextAct:
                editor.putString("mystring", "Hi");
                editor.commit();
                startActivity(new Intent("com.awplicity.testappshared.Main2Activity"));
                break;
        }
    }
}

这是第二项活动

package com.awplicity.testappshared;

import android.content.Context;
import android.content.SharedPreferences;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;

public class …