记事本
时间: 2023-10-11 21:22:51 浏览: 34
好的,以下是一个简单的安卓记事本的代码示例,包括了界面、文件读写和一些基本操作:
1. 在 layout 目录下创建一个名为 activity_main.xml 的布局文件,代码如下:
```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">
<EditText
android:id="@+id/editText"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="top|left"
android:inputType="textMultiLine"
android:hint="Type your notes here"/>
<LinearLayout
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<Button
android:id="@+id/saveButton"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Save"/>
<Button
android:id="@+id/loadButton"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Load"/>
<Button
android:id="@+id/clearButton"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Clear"/>
</LinearLayout>
</LinearLayout>
```
2. 在 MainActivity.java 中实现逻辑,代码如下:
```java
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import androidx.appcompat.app.AppCompatActivity;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
public class MainActivity extends AppCompatActivity {
private EditText editText;
private Button saveButton;
private Button loadButton;
private Button clearButton;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
editText = findViewById(R.id.editText);
saveButton = findViewById(R.id.saveButton);
loadButton = findViewById(R.id.loadButton);
clearButton = findViewById(R.id.clearButton);
saveButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String text = editText.getText().toString();
save(text);
}
});
loadButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String text = load();
editText.setText(text);
}
});
clearButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
editText.setText("");
}
});
}
private void save(String text) {
try {
FileOutputStream fos = openFileOutput("notes.txt", MODE_PRIVATE);
fos.write(text.getBytes());
fos.close();
Toast.makeText(this, "Saved successfully!", Toast.LENGTH_SHORT).show();
} catch (Exception e) {
e.printStackTrace();
Toast.makeText(this, "Save failed!", Toast.LENGTH_SHORT).show();
}
}
private String load() {
try {
FileInputStream fis = openFileInput("notes.txt");
InputStreamReader isr = new InputStreamReader(fis);
BufferedReader br = new BufferedReader(isr);
StringBuilder sb = new StringBuilder();
String line;
while ((line = br.readLine()) != null) {
sb.append(line).append("\n");
}
br.close();
isr.close();
fis.close();
Toast.makeText(this, "Loaded successfully!", Toast.LENGTH_SHORT).show();
return sb.toString();
} catch (Exception e) {
e.printStackTrace();
Toast.makeText(this, "Load failed!", Toast.LENGTH_SHORT).show();
return null;
}
}
}
```
3. 在 AndroidManifest.xml 中添加文件读写权限:
```xml
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
```
以上代码实现了一个简单的记事本功能,用户可以在编辑框中输入并保存,也可以读取之前保存的内容或清空编辑框。当然,这只是一个简单的示例,实际应用中还需要考虑更多的功能和安全性问题。