S's Journal

本範例將製作一個計算機，利用簡單的按鈕組合、不同的按鈕事件，來處理輸入的數字，輸入數字及點擊按鈕不同，結果也隨之不同。本範例為了使輸入小數時也可以使用，將數字都設為float(浮點數)，以避免例外錯誤發生。

小試身手小範例

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.Window;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class CalculatorExample extends Activity {
/** Called when the activity is first created. */
    public Button mButton01;
    public Button mButton02;
    public Button mButton03;
    public Button mButton04;
    public EditText mEditText01;
    public EditText mEditText02;
    public TextView mTextView01;
    public TextView mTextView02;
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
    WindowManager.LayoutParams.FLAG_FULLSCREEN);
    setContentView(R.layout.main);

    mTextView01 = (TextView)findViewById(R.id.TextView01);
    mTextView02 = (TextView)findViewById(R.id.TextView02);
    mEditText01 = (EditText)findViewById(R.id.EditText01);
    mEditText02 = (EditText)findViewById(R.id.EditText02);
    mButton01 = (Button)findViewById(R.id.ButtonAdd);
    mButton02 = (Button)findViewById(R.id.ButtonPlus);
    mButton03 = (Button)findViewById(R.id.ButtonMultiplied);
    mButton04 = (Button)findViewById(R.id.ButtonDivided);

    mButton01.setOnClickListener(new Button.OnClickListener(){
    @Override
    public void onClick(View v){
        mTextView01.setText("+");
        String strRet = Float.toString(Float.parseFloat(mEditText01.getText().toString())
        +Float.parseFloat(mEditText02.getText().toString()));
        mTextView02.setText(strRet);
        }
    });
    mButton02.setOnClickListener(new Button.OnClickListener(){
    @Override
    public void onClick(View v){
        mTextView01.setText("-");
        String strRet = Float.toString(Float.parseFloat(mEditText01.getText().toString())
        -Float.parseFloat(mEditText02.getText().toString()));
        mTextView02.setText(strRet);
        }
    });
    mButton03.setOnClickListener(new Button.OnClickListener(){
    @Override
    public void onClick(View v){
        mTextView01.setText("*");
        String strRet = Float.toString(Float.parseFloat(mEditText01.getText().toString())
        *Float.parseFloat(mEditText02.getText().toString()));
        mTextView02.setText(strRet);
        }
    });
    mButton04.setOnClickListener(new Button.OnClickListener(){
    @Override
    public void onClick(View v){
        mTextView01.setText("/");
        String strRet = Float.toString(Float.parseFloat(mEditText01.getText().toString())
        /Float.parseFloat(mEditText02.getText().toString()));
        mTextView02.setText(strRet);
        }
    });
  }
}

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_margin="20sp"
>
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/EditText01"
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="+"
android:id="@+id/TextView01"
android:layout_marginRight="10sp"
android:layout_marginLeft="10sp"
/>
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/EditText02"
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text=" = "
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="10sp"
android:layout_marginLeft="10sp"
android:id="@+id/TextView02"
/>
</LinearLayout>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_margin="20sp"
>
<Button
android:layout_width="60sp"
android:layout_height="wrap_content"
android:id="@+id/ButtonAdd"
android:text=" + "
android:layout_marginRight="10sp"
/>
<Button
android:layout_width="60sp"
android:layout_height="wrap_content"
android:id="@+id/ButtonPlus"
android:text=" - "
android:layout_marginRight="10sp"
/>
<Button
android:layout_width="60sp"
android:layout_height="wrap_content"
android:id="@+id/ButtonMultiplied"
android:text=" * "
android:layout_marginRight="10sp"
/>
<Button
android:layout_width="60sp"
android:layout_height="wrap_content"
android:id="@+id/ButtonDivided"
android:text=" / "
/>
</LinearLayout>
</LinearLayout>

androidSDK0096