为什么我的程序启动后强制退出啊
package com.example.calculator;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
public class MainActivity extends Activity implements OnClickListener{
Button btn_0;
Button btn_1;
Button btn_2;
Button btn_3;
Button btn_4;
Button btn_5;
Button btn_6;
Button btn_7;
Button btn_8;
Button btn_9;
Button btn_point;
Button btn_del;
Button btn_clear;
Button btn_equal;
Button btn_plus;
Button btn_minus;
Button btn_multiply;
Button btn_divide;
EditText et_input;
boolean clear_flag;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn_0 = (Button) findViewById(R.id.btn_0);
btn_1 = (Button) findViewById(R.id.btn_1);
btn_2 = (Button) findViewById(R.id.btn_2);
btn_3 = (Button) findViewById(R.id.btn_3);
btn_4 = (Button) findViewById(R.id.btn_4);
btn_5 = (Button) findViewById(R.id.btn_5);
btn_6 = (Button) findViewById(R.id.btn_6);
btn_7 = (Button) findViewById(R.id.btn_7);
btn_8 = (Button) findViewById(R.id.btn_8);
btn_9 = (Button) findViewById(R.id.btn_9);
btn_clear = (Button) findViewById(R.id.btn_clear);
btn_point = (Button) findViewById(R.id.btn_point);
btn_del = (Button) findViewById(R.id.btn_del);
btn_plus = (Button) findViewById(R.id.btn_plus);
btn_minus = (Button) findViewById(R.id.btn_minus);
btn_multiply = (Button) findViewById(R.id.btn_multiply);
btn_divide = (Button) findViewById(R.id.btn_divide);
btn_equal = (Button) findViewById(R.id.btn_equal);
et_input = (EditText) findViewById(R.id.ed_input);
btn_0.setOnClickListener(this);
btn_1.setOnClickListener(this);
btn_2.setOnClickListener(this);
btn_3.setOnClickListener(this);
btn_4.setOnClickListener(this);
btn_5.setOnClickListener(this);
btn_6.setOnClickListener(this);
btn_7.setOnClickListener(this);
btn_8.setOnClickListener(this);
btn_9.setOnClickListener(this);
btn_point.setOnClickListener(this);
btn_clear.setOnClickListener(this);
btn_del.setOnClickListener(this);
btn_plus.setOnClickListener(this);
btn_minus.setOnClickListener(this);
btn_multiply.setOnClickListener(this);
btn_divide.setOnClickListener(this);
btn_equal.setOnClickListener(this);
}
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
String str = et_input.getText().toString();
switch(v.getId()) {
case R.id.btn_0:
case R.id.btn_1:
case R.id.btn_2:
case R.id.btn_3:
case R.id.btn_4:
case R.id.btn_5:
case R.id.btn_6:
case R.id.btn_7:
case R.id.btn_8:
case R.id.btn_9:
case R.id.btn_point:
if(clear_flag) {
clear_flag = false;
et_input.setText("");
}
et_input.setText(str + ((Button)v).getText().toString());
break;
case R.id.btn_clear:
clear_flag = false;
et_input.setText("");
case R.id.btn_del:
if(clear_flag) {
clear_flag = false;
et_input.setText("");
}else if(str!=null && str.equals("")) {
et_input.setText(str.substring(0, str.length()-1));
}
break;
case R.id.btn_plus:
case R.id.btn_minus:
case R.id.btn_multiply:
case R.id.btn_divide:
if(clear_flag) {
clear_flag = false;
et_input.setText("");
}
et_input.setText(str + " " + ((Button)v).getText().toString() + " ");
break;
case R.id.btn_equal:
getResult();
break;
}
}
public void getResult() {
double result = 0;
String exp = et_input.getText().toString();
if(exp==null || exp.equals("")) {
return;
}
if(!exp.contains(" ")) {
return;
}
if(clear_flag) {
clear_flag = false;
return;
}
clear_flag = true;
String s1 = exp.substring(0, exp.indexOf(" "));
String op = exp.substring(exp.indexOf(" ")+1, exp.indexOf(" "+2));
String s2 = exp.substring(exp.indexOf(" ")+3);
if(!s1.equals("") && !s2.equals("")) {
double d1 = Double.parseDouble(s1);
double d2 = Double.parseDouble(s2);
if(op.equals("＋")) {
result = d1+d2;
}else if(op.equals("－")) {
result = d1-d2;
}else if(op.equals("×")) {
result = d1*d2;
}else if(op.equals("÷")) {
if(d2 == 0) {
result = 0;
}else{
result = d1/d2;
}
}
if(!s1.contains(".") && !s2.contains(".")) {
int r = (int)result;
et_input.setText(r + "");
}else {
et_input.setText(result + "");
}
}else if(!s1.contains("") && s2.contains("")) {
et_input.setText(exp);
}else if(s1.contains("") && !s2.contains("")) {
double d2 = Double.parseDouble(s2);
if(op.equals("＋")) {
result = 0+d2;
}else if(op.equals("－")) {
result = 0-d2;
}else if(op.equals("×")) {
result = 0;
}else if(op.equals("÷")) {
result = 0;
}
if(!s1.contains(".") && !s2.contains(".")) {
int r = (int)result;
et_input.setText(r + "");
}else {
et_input.setText(result + "");
}
}else {
et_input.setText("");
}
}
}
