文章结构
1、项目要求2、实现思路3、代码实现主文件子文件4、效果预览1、项目要求
其实老师的要求就是做一个简易的计算器，有两个文本框，一个按钮，然后实现加法即可。
但是我还是想做一个比较好康的计算器（如下），也可以借此写个博客和大家分享一下
2、实现思路
思路就是做一个和平时手机用的计算器差不多的即可。
六行：第一行是显示计算过程和结果的
第二行道第六行是放各种按钮的，直接看效果预览就知道了
By the way，这里我的计算器只是个很粗糙的版本，我已经把UI都搞好了，并且把一些简单的计算都做好了，大家只需要完善一下就可以达到自己的需求了！各位都是学过Java的，相信对大家来说应该不难吧！
代码太多，所以分为
主文件：MainActivity.java、activity_main.xml
子文件：
3、代码实现
主文件
废话不多说，直接上代码
MainActivity.java（这是java文件的代码内容）：
package cn.hillain.myapplication;import androidx.appcompat.app.AppCompatActivity;import android.os.Bundle;import android.view.View;import android.widget.TextView;import android.widget.Toast;public class MainActivity2 extends AppCompatActivity {private TextView input;private TextView result;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);input = this.findViewById(R.id.input);result = this.findViewById(R.id.result);}String input1 = "";String oper = "";String input2 = "";boolean flag = false;boolean input1_flag = false;public void oneOnClick(View view){if(view instanceof TextView){String oneText = ((TextView)view).getText().toString();if(flag){switch (oneText){case "C":input.setText("");result.setText("");input1 = "";input2 = "";oper ="";input1_flag=false;flag=false;break;}}else{switch (oneText){case "+/-":break;case "%":break;case "1":if(!input1_flag){input1 += "1";input.setText(input1);}else{input2 += "1";input.setText(input1+oper+input2);}break;case "2":if(!input1_flag){input1 += "2";input.setText(input1);}else{input2 += "2";input.setText(input1+oper+input2);}break;case "3":if(!input1_flag){input1 += "3";input.setText(input1);}else{input2 += "3";input.setText(input1+oper+input2);}break;case "4":if(!input1_flag){input1 += "4";input.setText(input1);}else{input2 += "4";input.setText(input1+oper+input2);}break;case "5":if(!input1_flag){input1 += "5";input.setText(input1);}else{input2 += "5";input.setText(input1+oper+input2);}break;case "6":if(!input1_flag){input1 += "6";input.setText(input1);}else{input2 += "6";input.setText(input1+oper+input2);}break;case "7":if(!input1_flag){input1 += "7";input.setText(input1);}else{input2 += "7";input.setText(input1+oper+input2);}break;case "8":if(!input1_flag){input1 += "8";input.setText(input1);}else{input2 += "8";input.setText(input1+oper+input2);}break;case "9":if(!input1_flag){input1 += "9";input.setText(input1);}else{input2 += "9";input.setText(input1+oper+input2);}break;case "0":if(!input1_flag){input1 += "0";input.setText(input1);}else{input2 += "0";input.setText(input1+oper+input2);}break;case ".":if(!input1_flag){input1 += ".";input.setText(input1);}else{input2 += ".";input.setText(input1+oper+input2);}break;case "÷":oper = "÷";input1_flag = true;input.setText(input1+oper+input2);break;case "*":oper = "*";input1_flag = true;input.setText(input1+oper+input2);break;case "-":oper = "-";input1_flag = true;input.setText(input1+oper+input2);break;case "+":oper = "+";input1_flag = true;input.setText(input1+oper+input2);break;case "=":float num1 = Float.valueOf(input1).floatValue();float num2 = Float.valueOf(input2).floatValue();if(oper.equals("+")){flag = true;result.setText(String.valueOf(num1+num2));}else if(oper.equals("-")){flag = true;result.setText(String.valueOf(num1-num2));}else if(oper.equals("*")){flag = true;result.setText(String.valueOf(num1*num2));}if(oper.equals("÷")){if (num2 == 0) {Toast.makeText(MainActivity2.this, "除数不能为0", Toast.LENGTH_LONG).show();}else{flag = true;result.setText(String.valueOf(num1/num2));}}break;}}}}}
activity_main.xml（layout中的xml文件）：
<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="/apk/res/android"android:orientation="vertical"android:layout_width="match_parent"android:layout_height="match_parent"><LinearLayoutandroid:layout_width="match_parent"android:orientation="horizontal"android:layout_height="100dp"><TextViewandroid:id="@+id/input"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_marginLeft="10dp"android:layout_marginTop="10dp"android:text=""android:textSize="30sp" /><TextViewandroid:id="@+id/result"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_marginLeft="195dp"android:layout_marginTop="50dp"android:text=""android:textSize="30sp" /></LinearLayout><LinearLayoutandroid:layout_width="match_parent"android:orientation="horizontal"android:layout_height="80dp"><TextViewandroid:id="@+id/C"android:onClick="oneOnClick"android:layout_width="0dp"android:layout_weight="1"android:layout_height="match_parent"android:gravity="center"android:textSize="30sp"android:background="@drawable/selector_gray1"android:text="C"/><TextViewandroid:id="@+id/zf"android:onClick="oneOnClick"android:layout_width="0dp"android:layout_weight="1"android:layout_height="match_parent"android:gravity="center"android:textSize="30sp"android:background="@drawable/selector_gray1"android:text="+/-"/><TextViewandroid:id="@+id/mo"android:onClick="oneOnClick"android:layout_width="0dp"android:layout_weight="1"android:layout_height="match_parent"android:gravity="center"android:textSize="30sp"android:background="@drawable/selector_gray1"android:text="%"/><TextViewandroid:id="@+id/chu"android:onClick="oneOnClick"android:layout_width="0dp"android:layout_weight="1"android:layout_height="match_parent"android:gravity="center"android:textSize="30sp"android:background="@drawable/selector_gray3"android:text="÷"/></LinearLayout><LinearLayoutandroid:layout_width="match_parent"android:orientation="horizontal"android:layout_height="80dp"><TextViewandroid:id="@+id/one"android:onClick="oneOnClick"android:layout_width="0dp"android:layout_weight="1"android:layout_height="match_parent"android:gravity="center"android:textSize="30sp"android:background="@drawable/selector_gray2"android:text="1"/><TextViewandroid:id="@+id/two"android:onClick="oneOnClick"android:layout_width="0dp"android:layout_weight="1"android:layout_height="match_parent"android:gravity="center"android:textSize="30sp"android:background="@drawable/selector_gray2"android:text="2"/><TextViewandroid:id="@+id/three"android:onClick="oneOnClick"android:layout_width="0dp"android:layout_weight="1"android:layout_height="match_parent"android:gravity="center"android:textSize="30sp"android:background="@drawable/selector_gray2"android:text="3"/><TextViewandroid:id="@+id/cheng"android:onClick="oneOnClick"android:layout_width="0dp"android:layout_weight="1"android:layout_height="match_parent"android:gravity="center"android:textSize="30sp"android:background="@drawable/selector_gray3"android:text="*"/></LinearLayout><LinearLayoutandroid:layout_width="match_parent"android:orientation="horizontal"android:layout_height="80dp"><TextViewandroid:id="@+id/four"android:onClick="oneOnClick"android:layout_width="0dp"android:layout_weight="1"android:layout_height="match_parent"android:gravity="center"android:textSize="30sp"android:background="@drawable/selector_gray2"android:text="4"/><TextViewandroid:id="@+id/five"android:onClick="oneOnClick"android:layout_width="0dp"android:layout_weight="1"android:layout_height="match_parent"android:gravity="center"android:textSize="30sp"android:background="@drawable/selector_gray2"android:text="5"/><TextViewandroid:id="@+id/six"android:onClick="oneOnClick"android:layout_width="0dp"android:layout_weight="1"android:layout_height="match_parent"android:gravity="center"android:textSize="30sp"android:background="@drawable/selector_gray2"android:text="6"/><TextViewandroid:id="@+id/jian"android:onClick="oneOnClick"android:layout_width="0dp"android:layout_weight="1"android:layout_height="match_parent"android:gravity="center"android:textSize="30sp"android:background="@drawable/selector_gray3"android:text="-"/></LinearLayout><LinearLayoutandroid:layout_width="match_parent"android:orientation="horizontal"android:layout_height="80dp"><TextViewandroid:id="@+id/seven"android:onClick="oneOnClick"android:layout_width="0dp"android:layout_weight="1"android:layout_height="match_parent"android:gravity="center"android:textSize="30sp"android:background="@drawable/selector_gray2"android:text="7"/><TextViewandroid:id="@+id/eight"android:onClick="oneOnClick"android:layout_width="0dp"android:layout_weight="1"android:layout_height="match_parent"android:gravity="center"android:textSize="30sp"android:background="@drawable/selector_gray2"android:text="8"/><TextViewandroid:id="@+id/nine"android:onClick="oneOnClick"android:layout_width="0dp"android:layout_weight="1"android:layout_height="match_parent"android:gravity="center"android:textSize="30sp"android:background="@drawable/selector_gray2"android:text="9"/><TextViewandroid:id="@+id/jia"android:onClick="oneOnClick"android:layout_width="0dp"android:layout_weight="1"android:layout_height="match_parent"android:gravity="center"android:textSize="30sp"android:background="@drawable/selector_gray3"android:text="+"/></LinearLayout><LinearLayoutandroid:layout_width="match_parent"android:orientation="horizontal"android:layout_height="80dp"><TextViewandroid:id="@+id/zero"android:onClick="oneOnClick"android:layout_width="0dp"android:layout_weight="2"android:layout_height="match_parent"android:gravity="center_vertical"android:paddingLeft="44dp"android:textSize="30sp"android:background="@drawable/selector_gray2"android:text="0"/><TextViewandroid:id="@+id/dian"android:onClick="oneOnClick"android:layout_width="0dp"android:layout_weight="1"android:layout_height="match_parent"android:gravity="center"android:textSize="30sp"android:background="@drawable/selector_gray2"android:text="."/><TextViewandroid:id="@+id/dengyu"android:onClick="oneOnClick"android:layout_width="0dp"android:layout_weight="1"android:layout_height="match_parent"android:gravity="center"android:textSize="30sp"android:background="@drawable/selector_gray3"android:text="="/></LinearLayout></LinearLayout>
子文件
selector_gray1.xml
<?xml version="1.0" encoding="utf-8"?><selector xmlns:android="/apk/res/android"><item android:state_pressed="true"android:drawable="@drawable/shape_rectangle_gray1"/><item android:drawable="@drawable/shape_rectangle_darkgray"/></selector>
selector_gray2.xml
<?xml version="1.0" encoding="utf-8"?><selector xmlns:android="/apk/res/android"><item android:state_pressed="true"android:drawable="@drawable/shape_rectangle_gray1"/><item android:drawable="@drawable/shape_rectangle_lightgray"/></selector>
selector_gray3.xml
<?xml version="1.0" encoding="utf-8"?><selector xmlns:android="/apk/res/android"><item android:state_pressed="true"android:drawable="@drawable/shape_rectangle_gray2"/><item android:drawable="@drawable/shape_rectangle_orange"/></selector>
shape_rectangle_darkgray.xml
<?xml version="1.0" encoding="utf-8"?><shape xmlns:android="/apk/res/android"android:shape="rectangle"><solid android:color="#D6D6D6"/><stroke android:color="#A1A1A1" android:width="1dp"/></shape>
shape_rectangle_gray1.xml
<?xml version="1.0" encoding="utf-8"?><shape xmlns:android="/apk/res/android"android:shape="rectangle"><solid android:color="#999999"/><stroke android:color="#A1A1A1" android:width="1dp"/></shape>
shape_rectangle_gray2.xml
<?xml version="1.0" encoding="utf-8"?><shape xmlns:android="/apk/res/android"android:shape="rectangle"><solid android:color="#b55f1c"/><stroke android:color="#A1A1A1" android:width="1dp"/></shape>
shape_rectangle_lightgray.xml
<?xml version="1.0" encoding="utf-8"?><shape xmlns:android="/apk/res/android"android:shape="rectangle"><solid android:color="#E0E0E0"/><stroke android:color="#A1A1A1" android:width="1dp"/></shape>
shape_rectangle_orange.xml
<?xml version="1.0" encoding="utf-8"?><shape xmlns:android="/apk/res/android"android:shape="rectangle"><solid android:color="#FF8D27"/><stroke android:color="#A1A1A1" android:width="1dp"/></shape>
4、效果预览
这么多代码，没有预览，估计大家都不想复制
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