xml：

<FrameLayout 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:background="#0099cc"     tools:context=".FullscreenActivity" >

    <HorizontalScrollView         android:background="#0099cc"         android:layout_width="fill_parent"         android:layout_height="fill_parent"         >        <LinearLayout         android:layout_width="wrap_content"         android:layout_height="fill_parent">

        <EditText             android:id="@+id/editNum1"             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:layout_gravity="center_vertical"             android:inputType="number"             android:text="0.0" />

        <TextView             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:layout_gravity="center_vertical"             android:text="+" />

        <EditText             android:id="@+id/editNum2"             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:layout_gravity="center_vertical"             android:inputType="number"             android:text="0.0" />

        <Button             android:id="@+id/btEqualTo"             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:layout_gravity="center_vertical"             android:text="等于" />

        <TextView             android:id="@+id/txtResult"             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:layout_gravity="center_vertical"             android:text="0.0" />

       </LinearLayout>     </HorizontalScrollView>

</FrameLayout>

java：

package testPackage.example.testapp;
import testPackage.example.testapp.util.SystemUiHider;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
/**
 * An example full-screen activity that shows and hides the system UI (i.e.
 * status bar and navigation/system bar) with user interaction.
 *
 * @see SystemUiHider
 */
public class FullscreenActivity extends Activity {
 
 private EditText etNum1;
 private EditText etNum2;
 private TextView tvResult;
 private Button btEqualTo;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_fullscreen);
        //获取界面对象
     etNum1=(EditText)findViewById(R.id.editNum1);
     etNum2=(EditText)findViewById(R.id.editNum2);
     tvResult=(TextView)findViewById(R.id.txtResult);
        btEqualTo=(Button)findViewById(R.id.btEqualTo);
       
        //添加 click
        btEqualTo.setOnClickListener(btEqualTo_Click());
    }
   
    //等于事件
    private View.OnClickListener btEqualTo_Click()
    {
  return new View.OnClickListener() {
   @Override
   public void onClick(View arg0) {
    
    double num1= Double.parseDouble(etNum1.getText().toString());
    double num2= Double.parseDouble(etNum2.getText().toString());
    double result=num1+num2;
    
    String value = String.valueOf(result);
    tvResult.setText(value);
   }
  };
    }
   
}

Android 加法程序