android开发实战-记账本APP（二）
继昨天的开发，继续完成今天的内容。
（一）开始构建一些业务逻辑，开始构建记账本的添加一笔记账的功能。
①对fab按钮的click时间进行修改，创建一个AlertDialog.Builder对象，因此我们给dialog添加一个布局，命名为new_cost_data.xml，位于他的布局很简单，我们只需要设置两个编辑框，和一个时间选择框即可。
new_cost_data.xml
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent" android:gravity="center"> <EditText android:id="@+id/et_cost_title" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_margin="4dp" android:hint="Cost Title"/> <EditText android:id="@+id/et_cost_money" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_margin="4dp" android:hint="Cost Money"/> <DatePicker android:id="@+id/dp_cost_data" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_margin="4dp" android:datePickerMode="spinner" android:calendarViewShown="false"/> </LinearLayout>
②然后回到主程序，在fab点击事件里创建一个 LayoutInflater用他来创建view，将新布局传到新建立的View对象，这样就可以获取到布局文件的内容，获取后将该布局设置给dialog对象，然后需要给dialog设置监听事件，当点击ok的监听事件，就将从布局中获取的信息传给一个CostBean对象，在用数据库进行添加，收集数据的mCostBeanList对象也要进行添加，最后再进行刷新（mAdapter.notifyDataSetChanged();），点击cancel就会取消该view界面，最后不要忘了显示该dialog。
MainActivity代码：
package com.example.xlfbook; import android.content.DialogInterface; import android.content.Intent; import android.database.Cursor; import android.os.Bundle; import com.google.android.material.floatingactionbutton.FloatingActionButton; import com.google.android.material.snackbar.Snackbar; import androidx.appcompat.app.AlertDialog; import androidx.appcompat.app.AppCompatActivity; import androidx.appcompat.widget.Toolbar; import android.os.Parcelable; import android.view.LayoutInflater; import android.view.View; import android.view.Menu; import android.view.MenuItem; import android.widget.DatePicker; import android.widget.EditText; import android.widget.ListView; import java.io.Serializable; import java.util.ArrayList; import java.util.List; public class MainActivity extends AppCompatActivity { private List<CostBean> mCostBeanList; private DatabaseHelper mdatabaseHelper; private CostListAdapter mAdapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Toolbar toolbar = findViewById(R.id.toolbar); setSupportActionBar(toolbar); mdatabaseHelper=new DatabaseHelper(this); mCostBeanList=new ArrayList<>(); ListView costList=(ListView)findViewById(R.id.lv_main); initCostData(); mAdapter = new CostListAdapter(this, mCostBeanList); costList.setAdapter(mAdapter); FloatingActionButton fab = findViewById(R.id.fab); fab.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { AlertDialog.Builder builder=new AlertDialog.Builder(MainActivity.this); LayoutInflater inflater=LayoutInflater.from(MainActivity.this); View viewDialog=inflater.inflate(R.layout.new_cost_data,null); final EditText title=(EditText) viewDialog.findViewById(R.id.et_cost_title); final EditText money=(EditText)viewDialog.findViewById(R.id.et_cost_money); final DatePicker date=(DatePicker) viewDialog.findViewById(R.id.dp_cost_data); builder.setView(viewDialog); builder.setTitle("New Cost"); builder.setPositiveButton("OK", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { CostBean costBean=new CostBean(); costBean.costTitle=title.getText().toString(); costBean.costMoney=money.getText().toString(); costBean.costDate=date.getYear()+"-"+(date.getMonth()+1)+"-"+date.getDayOfMonth(); mdatabaseHelper.insertCost(costBean); mCostBeanList.add(costBean); mAdapter.notifyDataSetChanged(); } }); builder.setNegativeButton("Cancel",null);//点击取消 builder.create().show();//显示dialog的布局 } }); } private void initCostData() { // mdatabaseHelper.deleteAllData(); /* CostBean costBean=new CostBean(); for (int i=0;i<6;i++) { costBean.costTitle=i+"imooc"; costBean.costDate="11-11"; costBean.costMoney="20"; mdatabaseHelper.insertCost(costBean); }*/ Cursor cursor=mdatabaseHelper.getAllCostData(); if(cursor!=null){ while(cursor.moveToNext()){ CostBean costBean1=new CostBean(); costBean1.costTitle=cursor.getString(cursor.getColumnIndex("cost_title")); costBean1.costDate=cursor.getString(cursor.getColumnIndex("cost_date")); costBean1.costMoney=cursor.getString(cursor.getColumnIndex("cost_money")); mCostBeanList.add(costBean1); } cursor.close(); } } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.menu_main, menu); return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { // Handle action bar item clicks here. The action bar will // automatically handle clicks on the Home/Up button, so long // as you specify a parent activity in AndroidManifest.xml. int id = item.getItemId(); //noinspection SimplifiableIfStatement if (id == R.id.action_chart) { Intent intent=new Intent(MainActivity.this,ChartsActivity.class); intent.putExtra("cost_list", (Serializable) mCostBeanList); startActivity(intent); return true; } return super.onOptionsItemSelected(item); } }
接下来简单的添加一笔帐单的功能已经可以实现，我们来添加一笔账单试试效果。
（二）开始制作图表
图表的制作我们会用到第三方库hellocharts，具体可以登录该网址查看————https://github.com/lecho/hellocharts-android
接下来在Android Studio中导入该库，在build中的dependencies中导入该github就可以了
接下来首先创建一个布局文件，来展示我们的chart图表。
chart_view
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent" android:padding="10dp"> <lecho.lib.hellocharts.view.LineChartView android:id="@+id/chart" android:padding="20dp" android:layout_width="match_parent" android:layout_height="match_parent" /> </LinearLayout>
然后再创建一个ChartsActivity.java，再修改主程序中的右上角的内容，在上面主程序的代码中可以看到，就是下面代码，把之前的setting改为chart
public boolean onOptionsItemSelected(MenuItem item) { // Handle action bar item clicks here. The action bar will // automatically handle clicks on the Home/Up button, so long // as you specify a parent activity in AndroidManifest.xml. int id = item.getItemId(); //noinspection SimplifiableIfStatement if (id == R.id.action_chart) { Intent intent=new Intent(MainActivity.this,ChartsActivity.class); intent.putExtra("cost_list", (Serializable) mCostBeanList); startActivity(intent); return true; } return super.onOptionsItemSelected(item); }
更改menu_main中的信息
<menu xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" tools:context="com.example.xlfbook.MainActivity"> <item android:id="@+id/action_chart" android:orderInCategory="100" android:title="Charts" app:showAsAction="never" /> </menu>
ChartsActivity.java
package com.example.xlfbook; import android.app.Activity; import android.content.Intent; import android.graphics.Color; import android.os.Bundle; import androidx.annotation.Nullable; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import java.util.TreeMap; import lecho.lib.hellocharts.model.Axis; import lecho.lib.hellocharts.model.AxisValue; import lecho.lib.hellocharts.model.ChartData; import lecho.lib.hellocharts.model.Line; import lecho.lib.hellocharts.model.LineChartData; import lecho.lib.hellocharts.model.PointValue; import lecho.lib.hellocharts.model.ValueShape; import lecho.lib.hellocharts.util.ChartUtils; import lecho.lib.hellocharts.view.Chart; import lecho.lib.hellocharts.view.LineChartView; public class ChartsActivity extends Activity { private LineChartView mChart; private Map<String,Integer> table = new TreeMap<>(); private LineChartData mData; @Override protected void onCreate(@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.chart_view); mChart = (LineChartView) findViewById(R.id.chart); mData = new LineChartData(); List<CostBean> allDate = (List<CostBean>) getIntent().getSerializableExtra("cost_list"); generateValues(allDate); generateData(); } private void generateData() { List<Line> lines = new ArrayList<>(); List<PointValue> values = new ArrayList<>(); int indexX = 0; for(Integer value : table.values()){ values.add(new PointValue(indexX, value)); indexX++; } Line line = new Line(values); line.setColor(ChartUtils.COLORS[0]); line.setShape(ValueShape.CIRCLE); line.setPointColor(ChartUtils.COLORS[1]); lines.add(line); mData.setLines(lines); mChart.setLineChartData(mData); } private void generateValues(List<CostBean> allDate) { if(allDate != null){ for (int i = 0; i < allDate.size(); i++) { CostBean costBean = allDate.get(i); String costDate = costBean.costDate; int costMoney = Integer.parseInt(costBean.costMoney); if(!table.containsKey(costDate)){ table.put(costDate,costMoney); }else { int originMoney = table.get(costDate); table.put(costDate,originMoney + costMoney); } } } } }
这就是由我们的数据生成的折线图，还有待完善（坐标线还没搞明白怎么添加）
至此，该记账本的简单记账功能以及图表显示功能得以实现。在真机上经过测试，可以使用。
github：https://github.com/happy-xlf/NoteBook
