private?void?getResult(){
????String?exp=et.getText().toString();
????if(exp==null||exp.equals("")){
????????return;
????}
????if(!exp.contains("?")){
????????return;
????}
????double?result=0;
????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(".")){
????????et.setText("出錯");
????}else?if(!s1.equals("")&&!s2.equals("")){
????????double?d1=Double.parseDouble(s1);
????????double?d2=Double.parseDouble(s2);

????????switch?(op){
????????????case?"*":
????????????????result=d1*d2;
????????????????break;
????????????case?"-":
????????????????result=d1-d2;
????????????????break;
????????????case?"/":
????????????????if(d2==0){
????????????????????result=0;
????????????????}else{
????????????????????result=d1/d2;
????????????????}
????????????????break;
????????????case?"+":
????????????????result=d1+d2;
????????????????break;
????????}

????????if(!s1.contains(".")&&!s2.contains(".")&&!op.equals("/")){
????????????int?r=(int)result;
????????????et.setText(r+"");
????????}else?if(op.equals("/")){?//即使s1和s2含有小數點，但是相除的結果可能是整數，需要再判斷
????????????int?r=(int)result;
????????????if(result-r!=0)
????????????????et.setText(result+"");
????????????else
????????????????et.setText(r+"");//即使s1和s2含有小數點，如果兩數相除的結果為整數，則輸出int型的結果
????????}else{
????????????et.setText(result+"");
????????}
????}else?if(!s1.equals("")&&s2.equals("")){
????????et.setText(s1+"");//s1不為空，s2為空時，按等號時，直接輸出s1.如：輸入："3+"，然后就按等號了，則直接輸出"3"
????}else?if(s1.equals("")&&!s2.equals("")){
????????et.setText("0");//s1為空，s2不為空，這輸出"0"
????}
}

別換主題也可以解決額

我按delete不會，但是按=就會，這是代碼的問題，沒有判斷運算符前后是否為運算符或小數點，或者是沒有在點擊運算符的時候檢查是否已經存在運算符以及在最后運算前檢查運算符前后是否只是一個小數點。

?= =別用eclipse ?記住Android studio 才是親兒子