android利用spinner选择加减乘除进行运算！

1、//.xml<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" > <EditText android:id="@+id/edt_test1" android:layout_width="60dip" android:layout_height="40dip" android:ems="10" android:inputType="number" android:textColor="#88e355" android:textSize="20sp" /> <Spinner android:id="@+id/spinner" android:layout_width="60dip" android:layout_height="40dip"/> <EditText android:id="@+id/edt_test2" android:layout_width="60dip" android:layout_height="40dip" android:ems="10" android:inputType="number" android:textColor="#88e355" android:textSize="20sp" /> <Button android:id="@+id/button1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="=" /> <TextView android:id="@+id/tv" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="" /></LinearLayout>

2、//.javapackage com.example.test1_2;import androi蟠校盯昂d.app.Activity;import android.app.AlertDialog;import android.os.Bundle;import android.text.TextUtils;import android.util.Log;import android.view.View;import android.widget.AdapterView;import android.widget.ArrayAdapter;import android.widget.Button;import android.widget.EditText;import android.widget.Spinner;import android.widget.TextView;public class MainActivity extends Activity { private Spinner spinner; private EditText editNum1; private EditText editNum2; private TextView result; private Button button; private String[] huansaun = {"+","-","×","÷"}; String flag; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); spinner = (Spinner) findViewById(R.id.spinner); editNum1 = (EditText) findViewById(R.id.edt_test1); editNum2 = (EditText) findViewById(R.id.edt_test2); button = (Button) findViewById(R.id.button1); result = (TextView) findViewById(R.id.tv); ArrayAdapter<String> huansuan_adapter = new ArrayAdapter<String>( this,android.R.layout.simple_spinner_dropdown_item,huansaun ); spinner.setAdapter(huansuan_adapter); spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() { @Override public void onItemSelected(AdapterView<?> parent, View view, int position, long id) { flag = spinner.getSelectedItem().toString(); Log.e("Dawangba", String.valueOf(position)); } @Override public void onNothingSelected(AdapterView<?> parent) { } }); button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { if (flag.equals("+")){ AddListener addListener = new AddListener(); addListener.onClick(v); } if (flag.equals("-")){ SubListener subListener = new SubListener(); subListener.onClick(v); } if (flag.equals("×")){ MulListener mulListener = new MulListener(); mulListener.onClick(v); } if (flag.equals("÷")){ DivListener divListener = new DivListener(); divListener.onClick(v); } } }); } private void showDialog(){ AlertDialog.Builder dialog = new AlertDialog.Builder(this); dialog.setTitle("错误"); dialog.setMessage("输入数字无效!"); dialog.setPositiveButton("确定",null); dialog.show(); } //加法操作 private class AddListener implements View.OnClickListener { public void onClick(View v) { if (TextUtils.isEmpty(editNum1.getText().toString()) || TextUtils.isEmpty(editNum2.getText().toString())){ showDialog(); } else { float number1 = Float.parseFloat((editNum1.getText().toString())); float number2 = Float.parseFloat((editNum2.getText().toString())); result.setText(number1 + number2 + ""); } } } //减法操作 private class SubListener implements View.OnClickListener { public void onClick(View v) { if (TextUtils.isEmpty(editNum1.getText().toString()) || TextUtils.isEmpty(editNum2.getText().toString())){ showDialog(); } else { float number1 = Float.parseFloat((editNum1.getText().toString())); float number2 = Float.parseFloat((editNum2.getText().toString())); result.setText(number1 - number2 + ""); } } } //乘法操作 private class MulListener implements View.OnClickListener { public void onClick(View v) { if (TextUtils.isEmpty(editNum1.getText().toString()) || TextUtils.isEmpty(editNum2.getText().toString())){ showDialog(); } else { float number1 = Float.parseFloat((editNum1.getText().toString())); float number2 = Float.parseFloat((editNum2.getText().toString())); result.setText(number1 * number2 + ""); } } } //除法操作 private class DivListener implements View.OnClickListener { public void onClick(View v) { if (TextUtils.isEmpty(editNum1.getText().toString()) || TextUtils.isEmpty(editNum2.getText().toString())){ showDialog(); } else { float number1 = Float.parseFloat((editNum1.getText().toString())); float number2 = Float.parseFloat((editNum2.getText().toString())); if (number2 == 0){ showDialog(); } else { result.setText(number1 / number2 + ""); } } } }}