eclipse android 简单计算器入门 相关问题。

Question

一个小型加法计算器，在输入框里输入数据，键入button后进入下一个activity显示了计算结果，这时候按下返回键，输入过的数据还会输入框在里面。请问，如何在按返回的同时，清空原有文本框EditView中输入过的内容，让我在下一次输入的时候，输入框里是空白？

此段为第一个页面

package dhu.qq.com;

import android.R.integer;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class ZuoyeActivity extends Activity {
    /** Called when the activity is first created. */
    private EditText et1;
    private EditText et2;
    private Button bt1;
    private Float f1, f2;

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

        et1 = (EditText) findViewById(R.id.et1);
        et2 = (EditText) findViewById(R.id.et2);
        bt1 = (Button) findViewById(R.id.bt1);

        bt1.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                f1 = Float.parseFloat(et1.getText().toString());
                f2 = Float.parseFloat(et2.getText().toString());


                Bundle bd1 = new Bundle();
                bd1.putFloat("iput1",f1);
                bd1.putFloat("iput2",f2);

                Intent itt1 = new Intent();
                itt1.putExtra("transfer_bundle", bd1);

                itt1.setClass(ZuoyeActivity.this, SecondyActivity.class);
                startActivity(itt1);

            }
        });
    }
}

此段为第二个页面

/**
 * 
 */
package dhu.qq.com;

import java.security.PublicKey;

import android.R.string;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;

/**
 * @author Administrator
 * 
 */
public class SecondyActivity extends Activity {

    /*
     * (non-Javadoc)
     * 
     * @see android.app.Activity#onCreate(android.os.Bundle)
     */
    private TextView tv21;
    private Float f1, f2, f3;
    private String str;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main2);
        tv21 = (TextView) findViewById(R.id.tv21);

        Intent itt2 = new Intent();
        Bundle bd12 = new Bundle();

        itt2 = this.getIntent();
        bd12 = itt2.getBundleExtra("transfer_bundle");
        f1 = bd12.getFloat("iput1");
        f2 = bd12.getFloat("iput2");
        f3 = f1 + f2;

        str = String.valueOf(f3);
        tv21.setText(str);

    }
}

最终效果如图

完全零基础入门求教，谢谢各位大神！

Answer 1

点击button跳转时设置输入框文字为空：
itt1.setClass(ZuoyeActivity.this, SecondyActivity.class);
//这个位置
et1.setText("");//设置空字符串
et2.setText("");//设置空字符串
startActivity(itt1);