安卓自制的计算器

这是本人自己用安卓编写的计算器，代码的优化可能有所问题，不过大家都在学习阶段，欢迎大家批评指正，还是上源码吧。

先上一波运行图

下面是XML文件

  1 <?xml version="1.0" encoding="utf-8"?>
  2 <LinearLayout
  3     xmlns:android="http://schemas.android.com/apk/res/android"
  4     xmlns:tools="http://schemas.android.com/tools"
  5     android:layout_width="match_parent"
  6     android:layout_height="match_parent"
  7     android:orientation="vertical"
  8     tools:context="com.example.nanchen.exam_1_1.MainActivity">
  9 
 10 
 11 
 12 
 13     <!--显示结果-->
 14     <LinearLayout
 15         android:layout_width="match_parent"
 16         android:layout_height="0dp"
 17         android:layout_weight="1">
 18         <TextView
 19             android:layout_width="match_parent"
 20             android:layout_height="match_parent"
 21             android:id="@+id/result"
 22             android:gravity="end"
 23             android:textSize="40sp"
 24             android:text="@string/zero"/>
 25     </LinearLayout>
 26 
 27     <LinearLayout
 28         android:layout_width="match_parent"
 29         android:layout_height="0dp"
 30         android:orientation="horizontal"
 31         android:layout_weight="1">
 32 
 33         <Button
 34             android:layout_width="0dp"
 35             android:layout_weight="1"
 36             android:layout_height="wrap_content"
 37             android:text="@string/clear"
 38             android:id="@+id/clear"
 39             android:textAllCaps="false"
 40             android:gravity="center"
 41             android:textSize="25sp"/>
 42 
 43         <Button
 44             android:layout_width="0dp"
 45             android:layout_weight="1"
 46             android:layout_height="wrap_content"
 47             android:text="@string/backspace"
 48             android:id="@+id/backSpace"
 49             android:textAllCaps="false"
 50             android:gravity="center"
 51             android:textSize="25sp"
 52             />
 53     </LinearLayout>
 54 
 55     <!--789/-->
 56     <LinearLayout
 57         android:layout_width="match_parent"
 58         android:layout_height="0dp"
 59         android:layout_weight="1">
 60         <Button
 61             android:layout_width="0dp"
 62             android:text="@string/seven"
 63             android:id="@+id/btn7"
 64             android:textSize="30sp"
 65             android:gravity="center"
 66             android:layout_height="wrap_content"
 67             android:layout_weight="1"/>
 68         <Button
 69             android:layout_width="0dp"
 70             android:text="@string/eight"
 71             android:id="@+id/btn8"
 72             android:textSize="30sp"
 73             android:gravity="center"
 74             android:layout_height="wrap_content"
 75             android:layout_weight="1"/>
 76         <Button
 77             android:layout_width="0dp"
 78             android:text="@string/nine"
 79             android:id="@+id/btn9"
 80             android:textSize="30sp"
 81             android:gravity="center"
 82             android:layout_height="wrap_content"
 83             android:layout_weight="1"/>
 84         <Button
 85             android:layout_width="0dp"
 86             android:text="@string/del"
 87             android:id="@+id/btn13"
 88             android:textSize="30sp"
 89             android:gravity="center"
 90             android:layout_height="wrap_content"
 91             android:layout_weight="1"/>
 92 
 93     </LinearLayout>
 94 
 95     <!--456*-->
 96     <LinearLayout
 97         android:layout_width="match_parent"
 98         android:layout_height="0dp"
 99         android:layout_weight="1">
100         <Button
101             android:layout_width="0dp"
102             android:text="@string/four"
103             android:id="@+id/btn4"
104             android:textSize="30sp"
105             android:gravity="center"
106             android:layout_height="wrap_content"
107             android:layout_weight="1"/>
108         <Button
109             android:layout_width="0dp"
110             android:text="@string/five"
111             android:id="@+id/btn5"
112             android:textSize="30sp"
113             android:gravity="center"
114             android:layout_height="wrap_content"
115             android:layout_weight="1"/>
116         <Button
117             android:layout_width="0dp"
118             android:text="@string/six"
119             android:id="@+id/btn6"
120             android:textSize="30sp"
121             android:gravity="center"
122             android:layout_height="wrap_content"
123             android:layout_weight="1"/>
124         <Button
125             android:layout_width="0dp"
126             android:text="@string/mul"
127             android:id="@+id/btn12"
128             android:textSize="30sp"
129             android:gravity="center"
130             android:layout_height="wrap_content"
131             android:layout_weight="1"/>
132 
133     </LinearLayout>
134 
135     <!--123- -->
136     <LinearLayout
137         android:layout_width="match_parent"
138         android:layout_height="0dp"
139         android:layout_weight="1">
140 
141         <Button
142             android:layout_width="0dp"
143             android:text="@string/one"
144             android:textSize="30sp"
145             android:id="@+id/btn1"
146             android:gravity="center"
147             android:layout_height="wrap_content"
148             android:layout_weight="1"/>
149         <Button
150             android:layout_width="0dp"
151             android:text="@string/two"
152             android:id="@+id/btn2"
153             android:textSize="30sp"
154             android:gravity="center"
155             android:layout_height="wrap_content"
156             android:layout_weight="1"/>
157         <Button
158             android:layout_width="0dp"
159             android:text="@string/three"
160             android:id="@+id/btn3"
161             android:textSize="30sp"
162             android:gravity="center"
163             android:layout_height="wrap_content"
164             android:layout_weight="1"/>
165         <Button
166             android:layout_width="0dp"
167             android:text="@string/sub"
168             android:id="@+id/btn11"
169             android:textSize="30sp"
170             android:gravity="center"
171             android:layout_height="wrap_content"
172             android:layout_weight="1"/>
173 
174     </LinearLayout>
175 
176     <!--0.=+-->
177     <LinearLayout
178         android:layout_width="match_parent"
179         android:layout_height="0dp"
180         android:layout_weight="1">
181 
182         <Button
183             android:layout_width="0dp"
184             android:text="@string/zero1"
185             android:id="@+id/btn0"
186             android:textSize="30sp"
187             android:gravity="center"
188             android:layout_height="wrap_content"
189             android:layout_weight="1"/>
190         <Button
191             android:layout_width="0dp"
192             android:text="@string/dec"
193             android:id="@+id/btn14"
194             android:textSize="30sp"
195             android:gravity="center"
196             android:layout_height="wrap_content"
197             android:layout_weight="1"/>
198         <Button
199             android:layout_width="0dp"
200             android:text="@string/equal"
201             android:id="@+id/btn15"
202             android:textSize="30sp"
203             android:gravity="center"
204             android:layout_height="wrap_content"
205             android:layout_weight="1"/>
206         <Button
207             android:layout_width="0dp"
208             android:text="@string/add"
209             android:id="@+id/btn10"
210             android:textSize="30sp"
211             android:gravity="center"
212             android:layout_height="wrap_content"
213             android:layout_weight="1"/>
214 
215     </LinearLayout>
216 
217 
218 
219     <LinearLayout
220         android:layout_weight="4"
221         android:orientation="vertical"
222         android:layout_width="match_parent"
223         android:layout_height="0dp">
224 
225         <TextView
226             android:layout_width="wrap_content"
227             android:layout_height="wrap_content"
228             android:textSize="20sp"
229             android:text="@string/string1"/>
230         <TextView
231             android:layout_width="wrap_content"
232             android:layout_height="wrap_content"
233             android:text="@string/string2"
234             android:textSize="20sp"/>
235 
236     </LinearLayout>
237 
238 
239 
240 </LinearLayout>

下面上活动的代码

  1 package com.example.nanchen.exam_1_1;
  2 
  3 import android.content.DialogInterface;
  4 import android.support.v7.app.AlertDialog;
  5 import android.support.v7.app.AppCompatActivity;
  6 import android.os.Bundle;
  7 import android.view.View;
  8 import android.widget.Button;
  9 import android.widget.TextView;
 10 
 11 public class MainActivity extends AppCompatActivity implements View.OnClickListener{
 12     private Button btn0;
 13     private Button btn1;
 14     private Button btn2;
 15     private Button btn3;
 16     private Button btn4;
 17     private Button btn5;
 18     private Button btn6;
 19     private Button btn7;
 20     private Button btn8;
 21     private Button btn9;
 22     private Button btnAdd;
 23     private Button btnSub;
 24     private Button btnMul;
 25     private Button btnDiv;
 26     private Button btnDec;
 27     private Button btnEqual;
 28     private Button btnClear;
 29     private Button btnBackSpace;
 30     private TextView textView_result;
 31 
 32     double num1 = 0,num2 = 0,result = 0;//定义存储结果和两个操作数
 33     boolean isCheckEqu = false;//检测是否点击了等于
 34     int op = 0;//定义运算符
 35     boolean hasDec = false;
 36     boolean hasOp = false;
 37 
 38 
 39 
 40     @Override
 41     protected void onCreate(Bundle savedInstanceState) {
 42         super.onCreate(savedInstanceState);
 43         setContentView(R.layout.activity_main);
 44 
 45         textView_result = (TextView) findViewById(R.id.result);
 46         btn0 = (Button) findViewById(R.id.btn0);
 47         btn1 = (Button) findViewById(R.id.btn1);
 48         btn2 = (Button) findViewById(R.id.btn2);
 49         btn3 = (Button) findViewById(R.id.btn3);
 50         btn4 = (Button) findViewById(R.id.btn4);
 51         btn5 = (Button) findViewById(R.id.btn5);
 52         btn6 = (Button) findViewById(R.id.btn6);
 53         btn7 = (Button) findViewById(R.id.btn7);
 54         btn8 = (Button) findViewById(R.id.btn8);
 55         btn9 = (Button) findViewById(R.id.btn9);
 56         btnAdd = (Button) findViewById(R.id.btn10);
 57         btnSub = (Button) findViewById(R.id.btn11);
 58         btnMul = (Button) findViewById(R.id.btn12);
 59         btnDiv = (Button) findViewById(R.id.btn13);
 60         btnDec = (Button) findViewById(R.id.btn14);
 61         btnEqual = (Button) findViewById(R.id.btn15);
 62         btnClear = (Button) findViewById(R.id.clear);
 63         btnBackSpace = (Button) findViewById(R.id.backSpace);
 64 
 65         btn0.setOnClickListener(this);
 66         btn1.setOnClickListener(this);
 67         btn2.setOnClickListener(this);
 68         btn3.setOnClickListener(this);
 69         btn4.setOnClickListener(this);
 70         btn5.setOnClickListener(this);
 71         btn6.setOnClickListener(this);
 72         btn7.setOnClickListener(this);
 73         btn8.setOnClickListener(this);
 74         btn9.setOnClickListener(this);
 75         btnAdd.setOnClickListener(this);
 76         btnSub.setOnClickListener(this);
 77         btnDec.setOnClickListener(this);
 78         btnDiv.setOnClickListener(this);
 79         btnEqual.setOnClickListener(this);
 80         btnMul.setOnClickListener(this);
 81         btnClear.setOnClickListener(this);
 82         btnBackSpace.setOnClickListener(this);
 83 
 84 
 85 
 86     }
 87 
 88     @Override
 89     public void onClick(View v) {
 90         switch (v.getId()){
 91             case R.id.btn0:
 92                 if(isCheckEqu){
 93                     textView_result.setText(null);
 94                     isCheckEqu=false;
 95                 }
 96                 String myString0 = textView_result.getText().toString();
 97                 if (myString0.equals("0")){
 98                     myString0 = "";
 99                 }
100                 myString0 += "0";
101                 textView_result.setText(myString0);
102                 break;
103             case R.id.btn1:
104                 if(isCheckEqu){
105                     textView_result.setText(null);
106                     isCheckEqu=false;
107                 }
108                 String myString1 = textView_result.getText().toString();
109                 if (myString1.equals("0")){
110                     myString1 = "";
111                 }
112                 myString1 += "1";
113                 textView_result.setText(myString1);
114                 break;
115             case R.id.btn2:
116                 if(isCheckEqu){
117                     textView_result.setText(null);
118                     isCheckEqu=false;
119                 }
120                 String myString2 = textView_result.getText().toString();
121                 if (myString2.equals("0")){
122                     myString2 = "";
123                 }
124                 myString2 += "2";
125                 textView_result.setText(myString2);
126                 break;
127             case R.id.btn3:
128                 if(isCheckEqu){
129                     textView_result.setText(null);
130                     isCheckEqu=false;
131                 }
132                 String myString3 = textView_result.getText().toString();
133                 if (myString3.equals("0")){
134                     myString3 = "";
135                 }
136                 myString3 += "3";
137                 textView_result.setText(myString3);
138                 break;
139             case R.id.btn4:
140                 if(isCheckEqu){
141                     textView_result.setText(null);
142                     isCheckEqu=false;
143                 }
144                 String myString4 = textView_result.getText().toString();
145                 if (myString4.equals("0")){
146                     myString4 = "";
147                 }
148                 myString4 += "4";
149                 textView_result.setText(myString4);
150                 break;
151             case R.id.btn5:
152                 if(isCheckEqu){
153                     textView_result.setText(null);
154                     isCheckEqu=false;
155                 }
156                 String myString5 = textView_result.getText().toString();
157                 if (myString5.equals("0")){
158                     myString5 = "";
159                 }
160                 myString5 += "5";
161                 textView_result.setText(myString5);
162                 break;
163             case R.id.btn6:
164                 if(isCheckEqu){
165                     textView_result.setText(null);
166                     isCheckEqu=false;
167                 }
168                 String myString6 = textView_result.getText().toString();
169                 if (myString6.equals("0")){
170                     myString6 = "";
171                 }
172                 myString6 += "6";
173                 textView_result.setText(myString6);
174                 break;
175             case R.id.btn7:
176                 if(isCheckEqu){
177                     textView_result.setText(null);
178                     isCheckEqu=false;
179                 }
180                 String myString7 = textView_result.getText().toString();
181                 if (myString7.equals("0")){
182                     myString7 = "";
183                 }
184                 myString7 += "7";
185                 textView_result.setText(myString7);
186                 break;
187             case R.id.btn8:
188                 if(isCheckEqu){
189                     textView_result.setText(null);
190                     isCheckEqu=false;
191                 }
192                 String myString8 = textView_result.getText().toString();
193                 if (myString8.equals("0")){
194                     myString8 = "";
195                 }
196                 myString8 += "8";
197                 textView_result.setText(myString8);
198                 break;
199             case R.id.btn9:
200                 if(isCheckEqu){
201                     textView_result.setText(null);
202                     isCheckEqu=false;
203                 }
204                 String myString9 = textView_result.getText().toString();
205                 if (myString9.equals("0")){
206                     myString9 = "";
207                 }
208                 myString9 += "9";
209                 textView_result.setText(myString9);
210                 break;
211 
212             case R.id.btn10:
213                 if (hasOp){
214                     doEqual();//显示出来当前的答案
215                 }
216                 String myStringAdd = textView_result.getText().toString();
217                 if(myStringAdd.equals(null)){
218                     return;
219                 }
220                 num1 = Double.valueOf(myStringAdd);
221                 textView_result.setText(null);// 这里被清除了
222                 op = 1;
223                 isCheckEqu = false;
224                 hasDec = false;
225                 hasOp = true;
226                 break;
227             case R.id.btn11:
228                 if (hasOp){
229                     doEqual();
230                 }
231                 String myStringSub = textView_result.getText().toString();
232                 if(myStringSub.equals(null)){
233                     return;
234                 }
235                 num1 = Double.valueOf(myStringSub);
236                 textView_result.setText(null);
237                 op = 2;
238                 isCheckEqu = false;
239                 hasDec = false;
240                 hasOp = true;
241                 break;
242             case R.id.btn12:
243                 if (hasOp){
244                     doEqual();
245                 }
246                 String myStringMul = textView_result.getText().toString();
247                 if(myStringMul.equals(null)){
248                     return;
249                 }
250                 num1 = Double.valueOf(myStringMul);
251                 textView_result.setText(null);
252                 op = 3;
253                 isCheckEqu = false;
254                 hasDec = false;
255                 hasOp = true;
256                 break;
257             case R.id.btn13:
258                 if (hasOp){
259                     doEqual();
260                 }
261                 String myStringDiv = textView_result.getText().toString();
262                 if(myStringDiv.equals(null)){
263                     return;
264                 }
265                 num1 = Double.valueOf(myStringDiv);
266                 textView_result.setText(null);
267                 op = 4;
268                 hasDec = false;
269                 isCheckEqu = false;
270                 hasOp = true;
271                 break;
272 
273             case R.id.btn14:
274                 if(isCheckEqu){
275                     textView_result.setText(null);
276                     isCheckEqu=false;
277                 }
278                 if(hasDec){//如果已经有小数点了,则弹出一个对话框
279                     AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
280                     builder.setTitle("警告");
281                     builder.setMessage("输入错误，一个数字不能有两个小数点！");
282                     builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {
283                         @Override
284                         public void onClick(DialogInterface dialog, int which) {
285 
286                         }
287                     });
288                     builder.show();
289                     return;
290                 }
291                 hasDec = true;
292                 String myString14 = textView_result.getText().toString();
293                 myString14 += ".";
294                 textView_result.setText(myString14);
295                 break;
296             case R.id.btn15:
297                 doEqual();
298                 hasOp = false;
299                 break;
300             case R.id.backSpace:
301                 String myString = textView_result.getText().toString();
302                 try {
303                     textView_result.setText(myString.substring(0,myString.length()-1));
304                 }catch (Exception e){
305                     textView_result.setText("0");
306                 }
307                 break;
308             case R.id.clear:
309                 textView_result.setText("0");
310                 break;
311             default:
312                 break;
313 
314         }
315     }
316 
317     /**
318      * 按下等于
319      */
320     private void doEqual(){
321         String myStringEqu=textView_result.getText().toString();
322         if(myStringEqu.equals(null))
323         {
324             return;
325         }
326         num2=Double.valueOf(myStringEqu);
327         textView_result.setText(null);
328         switch (op) {
329             case 0:
330                 result=num2;
331                 break;
332             case 1:
333                 result=num1+num2;
334                 break;
335             case 2:
336                 result=num1-num2;
337                 break;
338             case 3:
339                 result=num1*num2;
340                 break;
341             case 4:
342                 result=num1/num2;
343                 break;
344             default:
345                 result=0;
346                 break;
347         }
348         textView_result.setText(String.valueOf(result));
349         isCheckEqu=true;
350     }
351 }