Question

嘿我是Android开发新手，我在官方Android网站上使用该教程来帮助我创建一个应用程序。到目前为止，我已经创建了一个文本框，当你点击它时。它只是打开另一个屏幕并返回我的名字。如何将文本框中的输入作为数字并乘以另一个值。

这是我到目前为止的代码。

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.discountprice2.DisplayMessageActivity$PlaceholderFragment" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>



</RelativeLayout>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.discountprice2.MainActivity$PlaceholderFragment" >

    <EditText
        android:id="@+id/edit_message"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:ems="10"
        android:hint="@string/edit_message"
        android:inputType="text" />

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_alignTop="@+id/edit_message"
        android:text="@string/calc"
        android:onClick="sendMessage"  />

</RelativeLayout>

import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.app.ActionBarActivity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends ActionBarActivity {
    public final static String EXTRA_MESSAGE = "com.example.myfirstapp.MESSAGE";

    public void sendMessage(View view) {
        Intent intent = new Intent(this, DisplayMessageActivity.class);
        EditText editText=(EditText) findViewById(R.id.edit_message);
        TextView textView = (TextView) findViewById(R.id.textView1);




        String message =editText.getText().toString();
        intent.putExtra(EXTRA_MESSAGE, message);
        startActivity(intent);
        //get text from edittext and convert it to string
        String messageString=editText.getText().toString();

        //set string from edittext to textview
        textView.setText(messageString);

        //clear edittext after sending text to message
        //editText.setText("");


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

        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction()
                    .add(R.id.container, new PlaceholderFragment()).commit();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    /**
     * A placeholder fragment containing a simple view.
     */
    public static class PlaceholderFragment extends Fragment {

        public PlaceholderFragment() {
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_main, container,
                    false);
            return rootView;
        }
    }

}

Answer 1

假设数字是整数，请将sendMessage方法更改为：

public void sendMessage(View view) {
    Intent intent = new Intent(this, DisplayMessageActivity.class);
    EditText editText=(EditText) findViewById(R.id.edit_message);
    TextView textView = (TextView) findViewById(R.id.textView1);

    String message =editText.getText().toString();
    intent.putExtra(EXTRA_MESSAGE, message);
    startActivity(intent);
    //get text from edittext and convert it to string
    String messageString=editText.getText().toString();

    int myNumber = Integer.parseInt(messageString);
    myNumber = myNumber*100; //this is where you multiply

    messageString = Integer.toString(myNumber);

    //set string from edittext to textview
    textView.setText(messageString);

}

Answer 2

你从EditText获得的是String，你可以将它改为Integer：

 String message =editText.getText().toString();
 int intMessage = Integer.parseInt(message);
 int result = intMessage*10; //Now you can multiply with another value

Answer 3

首先，您必须读入文本字段的值并将其保存为字符串。然后，您必须将文本解析为数字并将其相乘。

EditText field = (EditText) findViewById(R.id.edit_message);
String text = field.getText.toString();
double d = Double.parseDouble(text);

Answer 4

试试这个简单的样本

String msg =editText.getText().toString();

int intMsg = Integer.parseInt(msg);

int result = intMsg*10;

如何从文本框中获取数字，并通过值获取多个数字

4 个答案: