Question

我是android studio的新手，我正在使用相同的2.3版本。我正在学习intent的概念。我创建了2个活动：Apples和Bananas.Each有一个textView和一个Button.Apples有一个editText。用户在editText中输入并单击按钮。然后香蕉打开，香蕉的textView变为。

我的问题是：单击按钮后，Bananas中的textView正在消失。我发现这是由于香蕉活动的java代码中的代码行所致：

//code for Apples activity
package com.awani.intent;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.content.Intent;
import android.view.MenuItem;
import android.view.View;
import android.view.Menu;
import android.widget.EditText;



public class Apples extends AppCompatActivity {

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

public void onClick(View view) {
    //create instance of intent class
    //this tells the app that the following is the activity which we want to launch on click of the button
    Intent I= new Intent(this,Bananas.class);

    //Refer to the input textfield in the activity
    final EditText applesInput=(EditText)findViewById(R.id.applesInput);
    //get the inuput from user
   String userMessage=applesInput.getText().toString();
    //pass this info to the net activity which will appear afterr this click
    I.putExtra("applesmessage",userMessage);//this method takes info from current activity in the form of k ey-value pair


    //launch the activity
    startActivity(I);

}
}


//code for activity Bananas
package com.awani.intent;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
import android.view.ViewGroup;
import android.widget.RelativeLayout;



public class Bananas extends AppCompatActivity {

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

    //we need this class to accept the extra infromation passed to it by some other activity
    Bundle applesData=getIntent().getExtras();//this extra information is stored in applesData
    //test if the data is null or there is something(so that to avoid error)
   if(applesData==null){
        return;
    }
    //now as error is taken care of,move forward
    String applesMessage=applesData.getString("applesMessage");//in the variable applesMessage we are storing the string we got from user by passing the key which we passed in putExtra method
    //refer to the textview in the banana activity
    final TextView bananasText=(TextView)findViewById(R.id.bananasText);
    bananasText.setText(applesMessage);//we change the text Bananas to the text which was input by user

}

public void onClick(View view) {
    //create instance of intent class
    //this tells the app that the following is the activity which we want to launch on click of the button
    Intent I= new Intent(this,Apples.class);

    //launch the activity
    startActivity(I);
}
}

但我不知道应该做些什么改变。以下是这两项活动的代码。

group by

Answer 1

在Bananas活动中更改获取值的关键，因为在First活动中，您将发送密钥为＆＃34; applesmessage＆＃34;在香蕉中你收到的是＃34; applesMessage＆＃34;

String applesMessage=applesData.getString("applesMessage");

到

String applesMessage=applesData.getString("applesmessage");

单击按钮后TextView消失

1 个答案: