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今天学取出文本文件里的内容,还是修改原来项目的mainactivity.java文件- package com.example.xinwei.filepersistencetest;
- import android.content.Context;
- import android.support.v7.app.AppCompatActivity;
- import android.os.Bundle;
- import android.text.TextUtils;
- import android.widget.EditText;
- import android.widget.Toast;
- import java.io.BufferedReader;
- import java.io.BufferedWriter;
- import java.io.FileInputStream;
- import java.io.FileNotFoundException;
- import java.io.FileOutputStream;
- import java.io.IOException;
- import java.io.InputStreamReader;
- import java.io.OutputStreamWriter;
- public class MainActivity extends AppCompatActivity {
- private EditText edit;
- @Override
- protected void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.activity_main);
- edit=(EditText)findViewById(R.id.edit);
- String inputText=load();
- if(TextUtils.isEmpty(edit.getText())){
- edit.setText(inputText);
- edit.setSelection(inputText.length());
- Toast.makeText(this, "Restoring succeeded", Toast.LENGTH_SHORT).show();
- }
- }
- @Override
- protected void onDestroy() {
- super.onDestroy();
- String inputText=edit.getText().toString();
- save(inputText);
- }
- private void save(String inputText) {
- FileOutputStream out=null;
- BufferedWriter writer=null;
- try {
- out=openFileOutput("data", Context.MODE_PRIVATE);
- writer=new BufferedWriter(new OutputStreamWriter(out));
- writer.write(inputText);
- } catch (FileNotFoundException e) {
- e.printStackTrace();
- } catch (IOException e) {
- e.printStackTrace();
- }finally {
- if(writer!=null){
- try {
- writer.close();
- } catch (IOException e) {
- e.printStackTrace();
- }
- }
- }
- }
- public String load(){
- FileInputStream in = null;
- BufferedReader reader= null;
- StringBuilder content = new StringBuilder();
- try {
- in = openFileInput("data");
- reader = new BufferedReader(new InputStreamReader(in));
- String line="";
- while((line=reader.readLine())!=null){
- content.append(line);
- }
- } catch (FileNotFoundException e) {
- e.printStackTrace();
- } catch (IOException e) {
- e.printStackTrace();
- }finally {
- if(reader!=null){
- try {
- reader.close();
- } catch (IOException e) {
- e.printStackTrace();
- }
- }
- }
- return content.toString();
- }
- }
复制代码
这里的load()函数就是取出文件的方法,也是依靠这个类里内置的openFileInput()方法,非常方便,这次我们一打开程序就会出现上次我们输入的内容了 |
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