Java Android:onSaveInstanceState。如何将条目保存到EditVew中？

我正在尝试将用户条目保存到表单中，但由于某些原因，我无法使其工作。当我关闭应用程序并重新启动时，数据不会出现

我的目标是，如果用户完成表单的一半时，应用程序被终止，那么当应用程序重新启动时，条目仍将保留。任何指导都将不胜感激

public class MainActivity extends Activity {
     public final static String EXTRA_FROM = "com.example.assignment1.FROM";
     public final static String EXTRA_TO = "com.example.assignment1.TO";
     public final static String EXTRA_CC = "com.example.assignment1.CC";
     public final static String EXTRA_BCC = "com.example.assignment1.BCC";
     public final static String EXTRA_SUBJECT = "com.example.assignment1.SUBJECT";
     public final static String EXTRA_COMPOSE = "com.example.assignment1.COMPOSE";

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

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }

    @Override
    protected void onSaveInstanceState(Bundle outState)
    {
        super.onSaveInstanceState(outState);
        EditText emailFrom =(EditText) findViewById(R.id.editEmailFrom);
        EditText emailTo =(EditText) findViewById(R.id.editEmailTo);
        EditText emailCc =(EditText) findViewById(R.id.editEmailCc);
        EditText emailBcc =(EditText) findViewById(R.id.editEmailBcc);
        EditText emailSubject =(EditText) findViewById(R.id.editEmailSubject);
        EditText emailCompose =(EditText) findViewById(R.id.editEmailCompose);

        String from = emailFrom.getText().toString();
        String to = emailTo.getText().toString();
        String cc = emailCc.getText().toString();
        String bcc = emailBcc.getText().toString();
        String subject = emailSubject.getText().toString();
        String compose = emailCompose.getText().toString();

        outState.putString(EXTRA_FROM, from);
        outState.putString(EXTRA_TO, to);
        outState.putString(EXTRA_CC, cc);
        outState.putString(EXTRA_BCC, bcc);
        outState.putString(EXTRA_SUBJECT, subject);
        outState.putString(EXTRA_COMPOSE, compose);
    }

    @Override
    protected void onRestoreInstanceState(Bundle savedState)
    {

        EditText emailFrom =(EditText) findViewById(R.id.editEmailFrom);
        EditText emailTo =(EditText) findViewById(R.id.editEmailTo);
        EditText emailCc =(EditText) findViewById(R.id.editEmailCc);
        EditText emailBcc =(EditText) findViewById(R.id.editEmailBcc);
        EditText emailSubject =(EditText) findViewById(R.id.editEmailSubject);
        EditText emailCompose =(EditText) findViewById(R.id.editEmailCompose);

        String from = savedState.getString(EXTRA_FROM);
        String to = savedState.getString(EXTRA_TO);
        String cc = savedState.getString(EXTRA_CC);
        String bcc = savedState.getString(EXTRA_BCC);
        String subject = savedState.getString(EXTRA_SUBJECT);
        String compose = savedState.getString(EXTRA_COMPOSE);

        emailFrom.setText(from);
        emailTo.setText(to);
        emailCc.setText(cc);
        emailBcc.setText(bcc);
        emailSubject.setText(subject);
        emailCompose.setText(compose);
    }

    public void emailSend (View sendButton) 
    {
        Intent intent = new Intent(this,DisplayEmailActivity.class);
        EditText emailFrom =(EditText) findViewById(R.id.editEmailFrom);
        EditText emailTo =(EditText) findViewById(R.id.editEmailTo);
        EditText emailCc =(EditText) findViewById(R.id.editEmailCc);
        EditText emailBcc =(EditText) findViewById(R.id.editEmailBcc);
        EditText emailSubject =(EditText) findViewById(R.id.editEmailSubject);
        EditText emailCompose =(EditText) findViewById(R.id.editEmailCompose);

        String from = emailFrom.getText().toString();
        String to = emailTo.getText().toString();
        String cc = emailCc.getText().toString();
        String bcc = emailBcc.getText().toString();
        String subject = emailSubject.getText().toString();
        String compose = emailCompose.getText().toString();

        intent.putExtra(EXTRA_FROM,from);
        intent.putExtra(EXTRA_TO,to);
        intent.putExtra(EXTRA_CC,cc);
        intent.putExtra(EXTRA_BCC,bcc);
        intent.putExtra(EXTRA_SUBJECT,subject);
        intent.putExtra(EXTRA_COMPOSE,compose);

        startActivity(intent);
    }
}

当我关闭应用程序并重新启动时，数据不会出现

当然。如果您关闭应用程序（例如，task killer），则保存的实例状态将消失。要处理这种情况，您需要将数据持久化到文件、数据库等

---

要测试saveInstanceState（）上的

是否有效，请旋转屏幕或进行其他类型的配置更改。
要保存一些项目，最好使用SharedReferences

不久前我在这篇文章中举了一个例子：

祝你好运。
你想实现什么目标？从由于方向更改而重新启动的应用程序或从用户退出的应用程序中恢复条目？从用户退出的应用程序中恢复条目。