package com.example.calculater; import android.os.Bundle; import android.support.v7.app.ActionBarActivity; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.widget.EditText; import android.widget.TextView; import android.widget.Toast; public class MainActivity extends ActionBarActivity { public final static String EXTRA_MESSAGE = "calulater.MESSAGE"; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.fragment_main); } public void Add(View view){ try{ EditText editText1 = (EditText) findViewById(R.id.num1); EditText editText2 = (EditText) findViewById(R.id.num2); String message1 = editText1.getText().toString(); String message2 = editText2.getText().toString(); float result; result=Float.parseFloat(message1)+Float.parseFloat(message2); TextView textview=(TextView)findViewById(R.id.result1); textview.setText(String.valueOf(result)); } catch(NumberFormatException e1){Toast.makeText(this, "only input integer please", 3).show();}} public void Sub(View view){ try{ EditText editText1 = (EditText) findViewById(R.id.num1); EditText editText2 = (EditText) findViewById(R.id.num2); String message1 = editText1.getText().toString(); String message2 = editText2.getText().toString(); float result; result=Float.parseFloat(message1)-Float.parseFloat(message2); TextView textview=(TextView)findViewById(R.id.result1); textview.setText(String.valueOf(result)); } catch(NumberFormatException e2){Toast.makeText(this, "only input integer please", 3).show();} } public void Mul(View view){ try{ EditText editText1 = (EditText) findViewById(R.id.num1); EditText editText2 = (EditText) findViewById(R.id.num2); String message1 = editText1.getText().toString(); String message2 = editText2.getText().toString(); float result; result=Float.parseFloat(message1)*Float.parseFloat(message2); TextView textview=(TextView)findViewById(R.id.result1); textview.setText(String.valueOf(result)); } catch(NumberFormatException e2){Toast.makeText(this, "only input integer please", 3).show();} } public void Div(View view){ try{ EditText editText1 = (EditText) findViewById(R.id.num1); EditText editText2 = (EditText) findViewById(R.id.num2); String message1 = editText1.getText().toString(); String message2 = editText2.getText().toString(); float result; result=Float.parseFloat(message1)/Float.parseFloat(message2); TextView textview=(TextView)findViewById(R.id.result1); textview.setText(String.valueOf(result)); } catch(NumberFormatException e2){Toast.makeText(this, "only input integer please", 3).show();} } /* @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); } }
源码如上,主要是添加button的单击事件的处理方法add,sub,mul,div.用了try-catch 结构处理异常。
ps:numberFormatException是java提供的数字格式化异常。做了toast,发现
输入的数据不是数字就会toast个提示。toast最后结尾要有个show()函数,否则显示不出来。