Question

我知道还有其他一些答案，我已经尝试过所有这些答案而无法让它发挥作用。我需要保存两个输出数据“brereton”和“hoppus”。我认为我的编码可以做得更好，但我对此很陌生，所以不要严厉地评判......提前得到任何帮助。

 package com.example.dpivl.teak101;

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;


public class Tab1 extends Fragment {

    EditText num1;
    EditText num2;
    EditText num3;
    TextView brereton;
    TextView hoppus;
    Button calculate;
    Button reset;
    double w = 0;
    double x = 0;
    double y = 0;
    double z = 0;
    double h = 0;




    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.tab_1, container, false);


        return v;


    }


    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);


        initControls();
    }



    private void initControls() {
        num1 = (EditText) getView().findViewById(R.id.editTextHeight);
        num2 = (EditText) getView().findViewById(R.id.editTextWidth);
        num3 = (EditText) getView().findViewById(R.id.editTextAmount);
        brereton = (TextView) getView().findViewById(R.id.answerBrereton);
        hoppus = (TextView) getView().findViewById(R.id.answerHoppus);
        calculate = (Button) getView().findViewById(R.id.buttonCalc);
        reset = (Button) getView().findViewById(R.id.reset);
        reset.setOnClickListener(new Button.OnClickListener() {
            @Override
            public void onClick(View v) {
                reset();
            }
        });
        calculate.setOnClickListener(new Button.OnClickListener() {

            @Override
            public void onClick(View v) {
                if  (num1.getText().toString().equals("")|| num2.getText().toString().equals("")|| num3.getText().toString().equals("")){
                    Toast.makeText(getActivity(),"Insert Measurements!",Toast.LENGTH_SHORT).show();
                }
                else {

                    calculate();
                }
            }
        });
    }


    private void calculate() {

            w = Double.parseDouble(num1.getText().toString());
            x = Double.parseDouble(num2.getText().toString());
            y = Double.parseDouble(num3.getText().toString());
            z = (x / 314) * (x / 314) * w * y;
            h = z * 0.7852;
            brereton.setText(Double.toString(z));
            hoppus.setText(Double.toString(h));

    }

    private void reset() {
        num1.setText("");
        num2.setText("");
        num3.setText("");
        brereton.setText("");
        hoppus.setText("");
    }


}

Answer 1

将textviews的文本保存在这样的包中：

@Override
    public void onSaveInstanceState(Bundle outState) {
        // TODO Auto-generated method stub
        outState.putString("brereton", brereton.getText().toString());
        outState.putString("hoppus", hoppus.getText().toString());
        super.onSaveInstanceState(outState);
    }

现在，当活动旋转时，将重新创建片段，并且UI组件将重新膨胀到视图层次结构中。初始化完成后（正如您在onActivityCreated回调中所做的那样），您可以在回调中使用该包，将文本设置为您的文本视图。

@Override
    public void onActivityCreated(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        initControls();
        super.onActivityCreated(savedInstanceState);
        if (savedInstanceState != null) {
            brereton.setText(savedInstanceState.getString("brereton"));
            hoppus.setText(savedInstanceState.getString("hoppus"));
        }

    }

希望这有帮助。

当屏幕改变方向时，如何在片段中使用onSaveInstanceState来保存输出？

1 个答案: