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| package com.example.file;
import androidx.appcompat.app.AppCompatActivity;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import static android.os.Environment.MEDIA_MOUNTED;
public class MainActivity extends AppCompatActivity {
TextView et, et2;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
et = (TextView) this.findViewById(R.id.et);
et2 = (TextView) this.findViewById(R.id.et2);
}
public void save(View v) throws Exception {
String name = "hello.txt";
String data = et.getText().toString();
FileOutputStream out = openFileOutput(name, Context.MODE_PRIVATE);
out.write(data.getBytes());
out.close();
Toast.makeText(this, "数据写入成功", Toast.LENGTH_SHORT).show();
}
public void read(View v) throws IOException {
String name = "hello.txt";
FileInputStream input = openFileInput(name);
byte[] buffer = new byte[input.available()];
input.read(buffer);
String content = new String(buffer);
input.close();
Log.e("输出", content);
et.setText(content);
Toast.makeText(this, "读取成功", Toast.LENGTH_SHORT).show();
}
public void outsave(View v) throws Exception {
String name = "hello.txt";
String data = et2.getText().toString();
String state = Environment.getExternalStorageState();
//判断SD卡是否可用
if (MEDIA_MOUNTED.equals(state)) {
File SDPath = Environment.getExternalStorageDirectory();
//获取SD卡路径
File file = new File(SDPath, name);
FileOutputStream out = new FileOutputStream(file);
out.write(data.getBytes());
out.close();
Toast.makeText(this, "外部数据写入成功", Toast.LENGTH_SHORT).show();
}
}
public void outread(View v) throws IOException {
String name = "hello.txt";
String state = Environment.getExternalStorageState();
//判断SD卡是否可用
if (MEDIA_MOUNTED.equals(state)) {
File SDPath = Environment.getExternalStorageDirectory();
//获取SD卡路径
File file = new File(SDPath, name);
FileInputStream input = new FileInputStream(file);
BufferedReader br = new BufferedReader(new InputStreamReader(input));
String content = br.readLine();
input.close();
Log.e("输出", content);
et2.setText(content);
Toast.makeText(this, "外部读取成功", Toast.LENGTH_SHORT).show();
}
}
}
|
