Question

我正在尝试在离开活动后实现两个方法以保存变量信息，但我在每个变量上都收到错误：markOne cannot be resolved to a variable。我已将两个方法放在OnCreate之外（我已经发布了下面的全班，展示了我如何实现onSaveInstanceState和onRestoreInstanceState方法。有人可以告诉我为什么变量没有被解决？我猜它是因为变量不能在onCreate（）之外访问，但我该如何解决这个问题呢？

public class CalcResult extends Activity implements OnClickListener{

    TextView result1,result2,result3;

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.result);

        final Intent intent1=new Intent(this,AboutActivity.class);
        final Intent intent2=new Intent(this,MainActivity.class);
        final Intent intent3=new Intent(this,MainActivity.class);



        final ViewGroup actionBarLayout = (ViewGroup) getLayoutInflater().inflate(
                R.layout.a,
                null);

        // Set up your ActionBar
        final ActionBar actionBar = getActionBar();
        actionBar.setDisplayShowHomeEnabled(false);
        actionBar.setDisplayShowTitleEnabled(false);
        actionBar.setDisplayShowCustomEnabled(true);
        actionBar.setCustomView(actionBarLayout);

        // You customization
        final int actionBarColor = getResources().getColor(R.color.action_bar);
        actionBar.setBackgroundDrawable(new ColorDrawable(actionBarColor));

        final Button actionBarHome = (Button) findViewById(R.id.action_bar_title);
        actionBarHome.setBackgroundResource(R.drawable.ic_action_back);
        actionBarHome.setOnClickListener(this);
        actionBarHome.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View view) {                

               startActivity(intent2);

            }

        });

        final Button actionBarInfo = (Button) findViewById(R.id.action_bar_staff);
        actionBarInfo.setBackgroundResource(R.drawable.ic_action_help);
        actionBarInfo.setOnClickListener(this);
        actionBarInfo.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View view) {                

               startActivity(intent1);

            }

        });


        final Button actionBarHoome = (Button) findViewById(R.id.action_bar_home);
        actionBarHoome.setBackgroundResource(R.drawable.appicon);
        actionBarHoome.setOnClickListener(this);
        actionBarHoome.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View view) {                

               startActivity(intent3);

            }

        });

        result1 = (TextView)findViewById(R.id.markOne);
        result2 = (TextView)findViewById(R.id.markTwo);
        result3 = (TextView)findViewById(R.id.markThree);

        Intent intent = getIntent();
        double markOne = intent.getDoubleExtra("number1", 0);
        double markTwo = intent.getDoubleExtra("number2", 0);
        double markThree = intent.getDoubleExtra("number3", 0);

        DecimalFormat df = new DecimalFormat("#.##");

        result1.setText(String.valueOf(df.format(markOne)+"mm"));
        result2.setText(String.valueOf(df.format(markTwo)+"mm"));
        result3.setText(String.valueOf(df.format(markThree)+"mm"));

    }

    //Two methods I'm trying to implement ->
    @Override
    protected final void onSaveInstanceState(final Bundle outState)
    {
        // Save variables.
        outState.putString("markOne", markOne);
        outState.putString("markTwo", markTwo);
        outState.putString("markThree", markThree);

    }

    @Override
    protected final void onRestoreInstanceState(final Bundle outState)
    {
        // Restore saved variables and reshow activities if they were open.
        markOne = outState.getString("markOne", "");
        markTwo = outState.getString("markTwo", "");
        markThree = outState.getString("markThree", "");

    }

}

Answer 1

你必须在行

下面定义全局变量

TextView result1,result2,result3;
double markOne,markTwo,markThree;

并替换

double markOne = intent.getDoubleExtra("number1", 0);
double markTwo = intent.getDoubleExtra("number2", 0);
double markThree = intent.getDoubleExtra("number3", 0);

与

markOne = intent.getDoubleExtra("number1", 0);
markTwo = intent.getDoubleExtra("number2", 0);
markThree = intent.getDoubleExtra("number3", 0);

离开活动时如何保存变量值？

1 个答案: