Android(安卓)Files的文件读取解析+代码案例

package com.example.file;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.ByteArrayOutputStream;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;public class MainActivity extends AppCompatActivity {    EditText edt;    Button btn;    TextView tv;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        edt = (EditText) findViewById(R.id.editText);        btn = (Button) findViewById(R.id.button);        tv = (TextView) findViewById(R.id.textView);        btn.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                WriteFiles(edt.getText().toString());                tv.setText(readFiles());            }        });    }    //保存文件内容    public void WriteFiles(String content){        try {            FileOutputStream fos = openFileOutput("a.txt",MODE_PRIVATE);            fos.write(content.getBytes());            fos.close();        } catch (FileNotFoundException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        }    }    //读取文件    public String readFiles(){        String content = null;        try {            FileInputStream fis =  openFileInput("a.txt");            ByteArrayOutputStream baos = new ByteArrayOutputStream();            byte[]buffer = new byte[1024];            int len = 0;            while ((len = fis.read(buffer))!=-1)            {                baos.write(buffer,0,len);            }            content = baos.toString();            fis.close();;            baos.close();        } catch (FileNotFoundException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        }        return content;    }}

<?xml version="1.0" encoding="utf-8"?>xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    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="com.example.file.MainActivity">            android:layout_width="wrap_content"        android:layout_height="200dp"        android:id="@+id/editText"        android:layout_alignParentTop="true"        android:layout_alignParentLeft="true"        android:layout_alignParentStart="true"        android:layout_alignParentRight="true"        android:layout_alignParentEnd="true" />            android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="New Button"        android:id="@+id/button"        android:layout_below="@+id/editText"        android:layout_centerHorizontal="true"        android:layout_marginTop="90dp" />            android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="New Text"        android:id="@+id/textView"        android:layout_below="@+id/button"        android:layout_alignParentRight="true"        android:layout_alignParentEnd="true"        android:layout_alignParentBottom="true"        android:layout_alignParentLeft="true"        android:layout_alignParentStart="true" />

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