寫一個簡單的Android計算器應用
阿新 • • 發佈:2018-12-20
最近學習Android,所以寫了一個計算器練手。裡面涉及到了基本的元件和佈局,還有sqlite資料庫,Intent方法。
有興趣的新手朋友可以直接貼程式碼來做做,增加寫學習的興趣。
專案結構如圖:
AuthorActivity.java
package com.example.android_test6_6_12;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
public class AuthorActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.author);
}
public void toFirst(View v){
Intent in = new Intent(AuthorActivity.this,MainActivity.class);
startActivity(in);
}
}
MainActivity.java
package com.example.android_test6_6_12; import java.util.Calendar; import java.util.Date; import android.R.integer; import android.app.Activity; import android.content.Intent; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.os.Bundle; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.widget.EditText; import android.widget.TextView; import android.widget.Toast; public class MainActivity extends Activity { private TextView tv,tv2; private String str= "0",first="",second = "",result = "0"; private SQLiteDatabase db; private EditText et; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); tv2 = (TextView) findViewById(R.id.et_input); tv = (TextView) findViewById(R.id.result); db = SQLiteDatabase.openOrCreateDatabase(this.getFilesDir()+"/data2.db", null); Calendar data = Calendar.getInstance(); String a = data.getTime()+""; try{ db.execSQL("create table saveData(id integer primary key autoincrement,data text);"); }catch(Exception e){ Toast.makeText(this, a, 1).show(); } } public void nine(View v){ if(str=="0"){ str = "9"; }else{ tv.setText(first); str = str + "9"; } tv2.setText(str); } public void eight(View v){ if(str=="0"){ str = "8"; }else{ tv.setText(first); str = str + "8"; } tv2.setText(str); } public void seven(View v){ if(str=="0"){ str = "7"; }else{ tv.setText(first); str = str + "7"; } tv2.setText(str); } public void six(View v){ if(str=="0"){ str = "6"; }else{ tv.setText(first); str = str + "6"; } tv2.setText(str); } public void five(View v){ if(str=="0"){ str = "5"; }else{ tv.setText(first); str = str + "5"; } tv2.setText(str); } public void four(View v){ if(str=="0"){ str = "4"; }else{ tv.setText(first); str = str + "4"; } tv2.setText(str); } public void three(View v){ if(str=="0"){ str = "3"; }else{ tv.setText(first); str = str + "3"; } tv2.setText(str); } public void two(View v){ if(str=="0"){ str = "2"; }else{ tv.setText(first); str = str + "2"; } tv2.setText(str); } public void one(View v){ if(str=="0"){ str = "1"; }else{ tv.setText(first); str = str + "1"; } tv2.setText(str); } public void zero(View v){ if(str=="0"){ str = "0"; }else{ tv.setText(first); str = str + "0"; } tv2.setText(str); } public void dot(View v){ if(str=="0"){ str = "0."; }else{ tv.setText(first); str = str + "."; } tv2.setText(str); } public void plus(View v){ if(str==""){ str = "0"+"+"; }else{ str = str +"+"; } tv2.setText(str); } public void minus(View v){ if(str==""){ str = "0"+"-"; }else{ str = str +"-"; } tv2.setText(str); } public void times(View v){ if(str==""){ str = "0"+"*"; }else{ str = str +"*"; } tv2.setText(str); } public void divide(View v){ if(str==""){ str = "0"+"/"; }else{ str = str +"/"; } tv2.setText(str); } public void eq(View v){ result = tv2.getText().toString(); String[] a = result.split("\\+|\\-|\\*|\\/"); String[] b = result.split("\\d+\\.?\\d?"); if(result.contains("*")||result.contains("/")){ for(int i=0;i<b.length;i++){ if(b[i].contains("*")){ double sum = (double)Integer.parseInt(a[i])*(double)Integer.parseInt(a[i-1]); a[i-1] = 0+""; a[i] = sum+""; b[i] = b[i-1]; }else if(b[i].contains("/")){ double sum = (double)Integer.parseInt(a[i-1])/(double)Integer.parseInt(a[i]); a[i-1] = 0+""; a[i] = sum+""; b[i] = b[i-1]; } } } if(result.contains("+")||result.contains("-")){ for(int i=0;i<b.length;i++){ if(b[i].contains("+")){ double sum = (double)Integer.parseInt(a[i])+(double)Integer.parseInt(a[i-1]); a[i-1] = 0+""; a[i] = sum+""; b[i] = b[i-1]; }else if(b[i].contains("-")){ double sum = (double)Integer.parseInt(a[i-1])-(double)Integer.parseInt(a[i]); a[i-1] = 0+""; a[i] = sum+""; b[i] = b[i-1]; } } } tv.setText(str); first = "="+a[a.length-1]; tv2.setText(first); second = str+first; str = ""; } public void clear(View v){ tv2.setText("0"); str = ""; } public void backspace(View v){ String[] str2 = str.split(""); str = ""; str2[str2.length-1]=""; for(String s:str2){ str = str +s; } tv2.setText(str); } public void saveDB(View v){ if(str!=""){ db.execSQL("insert into saveData values(null,'"+str+"');"); }else{ db.execSQL("insert into saveData values(null,'"+second+"');"); } Toast.makeText(this, "儲存成功!", 1).show(); } public void p_m(View v){ setContentView(R.layout.savedb_info); et = (EditText) findViewById(R.id.et_save); Cursor c = db.rawQuery("select * from saveData ", null); String text = "編號\t\t\t\t\t\t\t\t數值\n"; while(c.moveToNext()){ text = text +c.getInt(0)+"\t\t\t\t\t\t\t\t\t\t"+c.getString(1)+"\n"; } et.setText(text); } public void back(View v){ str = ""; setContentView(R.layout.activity_main); tv2 = (TextView) findViewById(R.id.et_input); tv = (TextView) findViewById(R.id.result); } public void author(View v){ Intent in = new Intent(MainActivity.this,AuthorActivity.class); startActivity(in); } }
activity_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.example.android_test6_6_12.MainActivity"
android:background="@drawable/girl"
android:orientation="vertical">
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text=""
android:textSize="36sp"
android:id="@+id/result"
android:gravity="right"
android:hint="暫不支援多數運算和小數點" />
<TextView
android:textSize="25sp"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/et_input"
android:numeric="integer"
android:gravity="right"/>
<TableLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:stretchColumns="0,1,2,3,4">
<TableRow >
<Button
android:textSize="25sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="C"
android:onClick="clear"/>
<Button
android:textSize="25sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="B"
android:onClick="backspace"/>
<Button
android:textSize="25sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="query"
android:onClick="p_m"/>
<Button
android:textSize="25sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="save"
android:onClick="saveDB"/>
</TableRow>
<TableRow >
<Button
android:textSize="25sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="7"
android:onClick="seven"/>
<Button
android:textSize="25sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="8"
android:onClick="eight"/>
<Button
android:textSize="25sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="9"
android:onClick="nine"/>
<Button
android:textSize="25sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="+"
android:onClick="plus"/>
</TableRow>
<TableRow >
<Button
android:textSize="25sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="4"
android:onClick="four"/>
<Button
android:textSize="25sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="5"
android:onClick="five"/>
<Button
android:textSize="25sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="6"
android:onClick="six"/>
<Button
android:textSize="25sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="-"
android:onClick="minus"/>
</TableRow>
<TableRow >
<Button
android:textSize="25sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="1"
android:onClick="one"/>
<Button
android:textSize="25sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="2"
android:onClick="two"/>
<Button
android:textSize="25sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="3"
android:onClick="three"/>
<Button
android:textSize="25sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="*"
android:onClick="times"/>
</TableRow>
<TableRow >
<Button
android:textSize="25sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="。"
/>
<Button
android:textSize="25sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="0"
android:onClick="zero"/>
<Button
android:textSize="25sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="="
android:onClick="eq"/>
<Button
android:textSize="25sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="/"
android:onClick="divide"/>
</TableRow>
<Button
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="作者資訊"
android:onClick="author"/>
</TableLayout>
</LinearLayout>
author.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:background="@drawable/boys"
>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="返回"
android:onClick="toFirst"
android:layout_gravity="right|bottom"/>
</LinearLayout>
savedb_info.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<Button
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="返回"
android:textSize="25sp"
android:onClick="back"/>
<EditText
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text=""
android:textSize="25sp"
android:id="@+id/et_save"/>
</LinearLayout>
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.android_test6_6_12"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="21"
android:targetSdkVersion="21" />
<application
android:allowBackup="true"
android:icon="@drawable/app_icon"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".AuthorActivity"
android:label="@string/app_name" >
</activity>
</application>
</manifest>
因為計算的邏輯程式碼有些考慮不全,所以有些小bug。執行結果如圖:
記得往drawable中放圖片。