android记事本源码
时间: 2023-10-16 08:07:29 浏览: 58
以下是一个简单的 Android 记事本应用的源码示例:
MainActivity.java:
```
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.EditText;
import android.widget.Toast;
import androidx.appcompat.app.AppCompatActivity;
import java.io.FileInputStream;
import java.io.FileOutputStream;
public class MainActivity extends AppCompatActivity {
EditText editText;
String fileName = "note.txt";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
editText = findViewById(R.id.editText);
try {
FileInputStream fileInputStream = openFileInput(fileName);
int read = -1;
StringBuffer buffer = new StringBuffer();
while ((read = fileInputStream.read()) != -1) {
buffer.append((char) read);
}
editText.setText(buffer.toString());
fileInputStream.close();
} catch (Exception e) {
e.printStackTrace();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main_menu, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.save_note) {
try {
FileOutputStream fileOutputStream = openFileOutput(fileName, MODE_PRIVATE);
fileOutputStream.write(editText.getText().toString().getBytes());
fileOutputStream.close();
Toast.makeText(this, "Note saved", Toast.LENGTH_SHORT).show();
} catch (Exception e) {
e.printStackTrace();
}
return true;
}
return super.onOptionsItemSelected(item);
}
}
```
activity_main.xml:
```
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
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=".MainActivity">
<EditText
android:id="@+id/editText"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:inputType="textMultiLine" />
</RelativeLayout>
```
main_menu.xml:
```
<menu xmlns:android="http://schemas.android.com/apk/res/android">
<item
android:id="@+id/save_note"
android:title="Save"
android:icon="@android:drawable/ic_menu_save"
android:showAsAction="always" />
</menu>
```
这个简单的记事本应用允许用户输入文本并将其保存到本地文件中。当应用程序启动时,它会尝试从文件中读取以前保存的文本。用户可以通过选项菜单中的“保存”按钮将编辑器中的文本保存到文件中。