報錯：else上有語法錯誤，請刪除此標記 private void getResult(){ String exp = et_input.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(" ")){ 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.equals("")&&s2.equals("")){ et_input.setText(exp); }else if(s1.equals("")&&!s2.equals("")){ 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(!s2.contains(".")){ int r = (int) result; et_input.setText(r+""); }else{ et_input.setText(result+""); }else{ et_input.setText(""); } } }