Android 创建txt文件存到SD卡,向txt文件写入内容,读出txt文件内容
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2024-01-24 18:27:04
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源码下载
https://download.csdn.net/download/qq_31939617/10519109 下载
先上图
MainActivity.class
package com.example.sz.txtdemo;
import android.os.Environment;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
public class MainActivity extends AppCompatActivity {
private static final String TAG = "MainActivity";
private EditText mInput;
private Button mWrite, mRead;
private TextView tv1, tv2;
private String a, b, c, d;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
writeTxt();
}
public void initView() {
mInput = findViewById(R.id.ed_input);
mWrite = findViewById(R.id.btn_write);
mRead = findViewById(R.id.btn_read);
tv1 = findViewById(R.id.tv_tv1);
tv2 = findViewById(R.id.tv_tv2);
mRead.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//读取文件
readTxt();
}
});
}
public void writeTxt() {
//新建文件夹
String folderName = "User";
File sdCardDir = new File(Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_DOWNLOADS), folderName);
if (!sdCardDir.exists()) {
if (!sdCardDir.mkdirs()) {
try {
sdCardDir.createNewFile();
} catch (Exception e) {
e.printStackTrace();
}
}
}
try {
//新建文件
File saveFile = new File(sdCardDir, "user.txt");
if (!saveFile.exists()) {
saveFile.createNewFile();
}
// FileOutputStream outStream =null;
//outStream = new FileOutputStream(saveFile);
final FileOutputStream outStream = new FileOutputStream(saveFile);
mWrite.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String str = mInput.getText().toString().trim();
try {
outStream.write(str.getBytes());
outStream.close();
} catch (IOException e) {
e.printStackTrace();
Log.e(TAG, "onClick: --------------" + e.toString());
}
Toast.makeText(MainActivity.this, "写入成功", Toast.LENGTH_SHORT).show();
tv1.setText(str);
}
});
//outStream.write("测试写入文件".getBytes());
//outStream.close();
} catch (Exception e) {
e.printStackTrace();
}
}
public void readTxt() {
BufferedReader bre = null;
String str = null;
try {
String file = Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_DOWNLOADS) + "/User/user.txt";
bre = new BufferedReader(new FileReader(file));//此时获取到的bre就是整个文件的缓存流
while ((str = bre.readLine()) != null) { // 判断最后一行不存在,为空结束循环
Log.e(TAG, "readTxt: a------------" + str);
String[] arr = str.split("\\s+");
for (String ss : arr) {
a = arr[0];
}
tv2.setText(str);
}
} catch (Exception e) {
Log.e(TAG, "readTxt: ---------------" + e.toString());
}
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:orientation="vertical"
tools:context=".MainActivity">
<EditText
android:id="@+id/ed_input"
android:layout_width="100dp"
android:layout_height="wrap_content" />
<Button
android:id="@+id/btn_write"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
android:text="写入文件"/>
<TextView
android:id="@+id/tv_tv1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
android:text="Hello World!" />
<Button
android:id="@+id/btn_read"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
android:text="读取文件"/>
<TextView
android:id="@+id/tv_tv2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="20dp"
android:text="Hello World!" />
</LinearLayout>
源码下载
https://download.csdn.net/download/qq_31939617/10519109 下载
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