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一、设计目的
- 掌握首选项方式的存储和读取
- 掌握位于内存上的数据文件的存储和读取
- 掌握位于SD卡上的数据文件的存储和读取
二、设计内容
实现基于文件存储的日程安排应用，数据文件可以保存在机身内存或者SD卡中。通过单击增加图标打开新增加活动界面，通过单击保存按钮将活动内容写入到文件中，并返回前页,点击删除图标，可以删除该活动。
三、软硬件环境及系统所采用的体系结构
开发环境：Android Studio
模拟运行：Android Emulator – Nexus_5X_API_24
四、实现过程及结果
4.1 修改主布局如下所示：
<RelativeLayout xmlns:android = "http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="@+id/title"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="已安排的活动"
android:background="#777"
android:textColor="#ddd"
android:textSize="16pt"
android:gravity="center" />
<ListView
android:id="@+id/listView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/title"
android:layout_alignLeft="@+id/title">
</ListView>
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerInParent="true"
android:cropToPadding="false"
android:onClick="add"
android:src="@mipmap/add" />
</RelativeLayout>
完成后的界面如图所示：
4.2 1． 修改主Activity文件，通过getList()方法从文件itme_me中读取数据显示到ListView组件中。单击新增打开增加活动界面，新增活动界面关闭返回时在onActivityResult()方法中再次调用getItemList()方法获取最新数据并显示：
public class MainActivity extends AppCompatActivity {
private ListView itemList;
private void getItemList() throws IOException {
ArrayList<String> list = new ArrayList<String>();
try {
FileInputStream in = openFileInput("item_me");
BufferedReader br = new BufferedReader(new InputStreamReader(in));
String line = "";
while ((line = br.readLine()) != null) {
list.add(line);
}
br.close();
in.close();
String[] contents = {};
String[] allItem = list.toArray(contents);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,android.R.layout.simple_expandable_list_item_1,allItem);
itemList.setAdapter(adapter);
}
catch (Exception e) {
e.printStackTrace();
}
}
@Override
protected void onCreate(Bundle savedInstanceState) {
requestWindowFeature(Window.FEATURE_NO_TITLE);
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
itemList = (ListView) findViewById(R.id.listView);
try {
getItemList();
} catch (IOException e) {
e.printStackTrace();
Toast.makeText(this,e.toString(),Toast.LENGTH_LONG).show();
}
}
public void add(View view){
Intent intent = new Intent(MainActivity.this,AddItemActivity.class);
startActivityForResult(intent,0x111);
}
protected void onActivityResult(int requestCode, int resultCode, Intent data){
super.onActivityResult(requestCode,resultCode,data);
if(requestCode == 0x111 && resultCode == 0x111){
try {
getItemList();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
4.3 创建增加活动界面布局文件additem.xml:
<LinearLayout xmlns:android = "http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="新增活动"
android:background="#777"
android:textColor="#ddd"
android:textSize="16pt"
android:gravity="center"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="日期"
android:textSize="10pt"/>
<EditText
android:id="@+id/date"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:onClick="chooseDate"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="开始时间"
android:textSize="10pt"/>
<EditText
android:id="@+id/startTime"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:onClick="chooseStartTime"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="结束时间"
android:textSize="10pt"/>
<EditText
android:id="@+id/endTime"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:onClick="chooseEndTime"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="活动说明"
android:textSize="10pt"/>
<EditText
android:id="@+id/item"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<Button
android:id="@+id/save"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="save"
android:text="保存"
android:layout_gravity="center"/>
</LinearLayout>
完成后的界面如图所示：
4.4 创建增加活动界面Activity文件AddItemActivity.java,输入新增活动的日期、开始时间、结束时间、活动名称，保存到文件item_me中：
public class AddItemActivity extends AppCompatActivity {
private EditText date,startTime,endTime,item;
@Override
protected void onCreate(Bundle savedInstanceState) {
requestWindowFeature(Window.FEATURE_NO_TITLE);
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
super.onCreate(savedInstanceState);
setContentView(R.layout.additem);
date = (EditText) findViewById(R.id.date);
startTime = (EditText) findViewById(R.id.startTime);
endTime = (EditText) findViewById(R.id.endTime);
item = (EditText) findViewById(R.id.item);
}
public void chooseDate(View view){
DatePickerDialog datepd = new DatePickerDialog(this, new DatePickerDialog.OnDateSetListener() {
@Override
public void onDateSet(DatePicker dp, int year, int month, int day) {
date.setText(year + "-" + (month+1)+"-"+day);
}
},2018,5,20);
datepd.setMessage("请选择日期");
datepd.show();
}
public void chooseStartTime(View view){
TimePickerDialog timepd = new TimePickerDialog(this, new TimePickerDialog.OnTimeSetListener() {
@Override
public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
startTime.setText(hourOfDay + ":" + minute);
}
},10,0,true);
timepd.setMessage("请选择开始时间");
timepd.show();
}
public void chooseEndTime(View view){
TimePickerDialog timepd = new TimePickerDialog(this, new TimePickerDialog.OnTimeSetListener() {
@Override
public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
endTime.setText(hourOfDay + ":" + minute);
}
},12,0,true);
timepd.setMessage("请选择结束时间");
timepd.show();
}
public void save(View view){
StringBuilder result = new StringBuilder();
result.append(date.getText().toString()+" ");
result.append(startTime.getText().toString()+"-");
result.append(endTime.getText().toString()+" ");
result.append(item.getText().toString());
try{
FileOutputStream out = openFileOutput("item_me",MODE_APPEND);
PrintStream ps = new PrintStream(out);
ps.println(result.toString());
ps.close();
out.close();
Toast.makeText(this,"保存完毕！",Toast.LENGTH_LONG).show();
Intent intent = getIntent();
setResult(0x111,intent);
finish();
}
catch (Exception e){
e.printStackTrace();
}
}
}
