慕课网/安卓攻城狮视频学习及练习（五）——简陋计算器

  1 public class FActivity extends Activity implements OnClickListener{
  2     Button btn_0;
  3     Button btn_1;
  4     Button btn_2;
  5     Button btn_3;
  6     Button btn_4;
  7     Button btn_5;
  8     Button btn_6;
  9     Button btn_7;
 10     Button btn_8;
 11     Button btn_9;
 12     Button btn_point;
 13     Button btn_clear;
 14     Button btn_delete;
 15     Button btn_add;
 16     Button btn_minus;
 17     Button btn_multiple;
 18     Button btn_divide;
 19     Button btn_equal;
 20     private EditText et;
 21     String string;
 22     Boolean flag=false;
 23   @Override
 24 protected void onCreate(Bundle savedInstanceState) {
 25     // TODO Auto-generated method stub
 26     super.onCreate(savedInstanceState);
 27     setContentView(R.layout.factivity);
 28 
 29     btn_0=(Button) findViewById(R.id.button_0);
 30     btn_1=(Button) findViewById(R.id.button_1);
 31     btn_2=(Button) findViewById(R.id.button_2);
 32     btn_3=(Button) findViewById(R.id.button_3);
 33     btn_4=(Button) findViewById(R.id.button_4);
 34     btn_5=(Button) findViewById(R.id.button_5);
 35     btn_6=(Button) findViewById(R.id.button_6);
 36     btn_7=(Button) findViewById(R.id.button_7);
 37     btn_8=(Button) findViewById(R.id.button_8);
 38     btn_9=(Button) findViewById(R.id.button_9);
 39     btn_point=(Button) findViewById(R.id.button_point);
 40     btn_divide=(Button) findViewById(R.id.button_divide);
 41     btn_add=(Button) findViewById(R.id.button_add);
 42     btn_minus=(Button) findViewById(R.id.button_minus);
 43     btn_multiple=(Button) findViewById(R.id.button_multiple);
 44     btn_delete=(Button) findViewById(R.id.button_delete);
 45     btn_equal=(Button) findViewById(R.id.button_equal);
 46     btn_clear=(Button) findViewById(R.id.button_clear);
 47     et=(EditText) findViewById(R.id.editText1);
 48 
 49         btn_0.setOnClickListener(this);
 50         btn_1.setOnClickListener(this);
 51         btn_2.setOnClickListener(this);
 52         btn_3.setOnClickListener(this);
 53         btn_4.setOnClickListener(this);
 54         btn_5.setOnClickListener(this);
 55         btn_6.setOnClickListener(this);
 56         btn_7.setOnClickListener(this);
 57         btn_8.setOnClickListener(this);
 58         btn_9.setOnClickListener(this);
 59         btn_point.setOnClickListener(this);
 60         btn_delete.setOnClickListener(this);
 61         btn_add.setOnClickListener(this);
 62         btn_minus.setOnClickListener(this);
 63         btn_multiple.setOnClickListener(this);
 64         btn_divide.setOnClickListener(this);
 65         btn_equal.setOnClickListener(this);
 66         btn_clear.setOnClickListener(this);
 67 
 68 
 69 }
 70   @Override
 71   public void onClick(View v) {
 72       string=et.getText().toString();
 73 
 74     switch (v.getId()) {
 75     case R.id.button_0:
 76     case R.id.button_1:
 77     case R.id.button_2:
 78     case R.id.button_3:
 79     case R.id.button_4:
 80     case R.id.button_5:
 81     case R.id.button_6:
 82     case R.id.button_7:
 83     case R.id.button_8:
 84     case R.id.button_9:
 85     case R.id.button_point:
 86         {
 87             if (flag){
 88                 flag=false;
 89                 string="";
 90 
 91             }
 92             et.setText(string+((Button)v).getText());
 93 
 94         break;
 95         }
 96     case R.id.button_add:
 97     case R.id.button_minus:
 98     case R.id.button_multiple:
 99     case R.id.button_divide:
100         {
101             et.setText(string+" "+((Button)v).getText()+" ");
102 
103         break;
104         }
105   case R.id.button_clear:
106     {
107         et.setText("");
108 
109     break;
110     }
111   case R.id.button_delete:
112   {
113       if (!string.equals("")){
114       string=string.substring(0,string.length()-1); 
115         et.setText(string);
116 
117       }
118     break;
119   }
120   case R.id.button_equal:
121     { 
122     getResult();
123     break;      
124     }
125     }
126     }
127   private void getResult(){
128       string=et.getText().toString();
129       Double result=(double) 0;
130       if (string=="")
131           return;
132       if (!string.contains(" "))
133           return;
134       if (flag){
135          // flag=false;
136           return;
137       }
138       flag=true;
139       String s1=string.substring(0,string.indexOf(" "));
140       String op=string.substring(string.indexOf(" ")+1,string.indexOf(" ")+2);
141       String s2=string.substring(string.indexOf(" ")+3);
142 
143       double num1=Double.parseDouble(s1);
144       double num2=Double.parseDouble(s2);
145 
146 
147     if (!s1.equals("")&&!s2.equals("")){
148          if (op.equals("+")){
149           result=num1+num2;
150       }
151        if (op.equals("-")){
152           result=num1-num2;
153 
154       }
155        if (op.equals("*")){
156           result=num1*num2;
157 
158        }
159        if (op.equals("÷")){
160           if (num2!=0)
161           result=num1/num2;
162           else
163               result=0.0;
164 
165        }    
166     }else if (s1.equals("")&&!s2.equals("")){
167         result=num2;
168     }else if (!s1.equals("")&&s2.equals("")){
169         result=num1;
170     }
171 
172    et.setText(result+"");
173 }
174 
175 }