Io编程：内存卡和sd卡。字符串存入内存卡然后读出来。

activity:

package com.sxt.day06_06;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.io.UnsupportedEncodingException;import android.app.Activity;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.EditText;import android.widget.Toast;public class MainActivity extends Activity {    EditText met;//文本框    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        initView();        setListener();    }    private void setListener() {        setSaveDataClickListener();        setReadDataClickListener();    }    private void setReadDataClickListener() {        findViewById(R.id.btnReadData).setOnClickListener(new OnClickListener() {            @Override            public void onClick(View v) {                FileInputStream in =null;                try {                    in= openFileInput("file.dat");                    byte[] data=new byte[1024];                    int len = in.read(data);//返回实际读取的字节数                    String text=new String(data, 0, len, "utf-8");                    Toast.makeText(MainActivity.this, text, 3000).show();                } catch (FileNotFoundException e) {                    e.printStackTrace();                } catch (IOException e) {                    e.printStackTrace();                }finally{                    if(in!=null){                        try {                            in.close();                        } catch (IOException e) {                            e.printStackTrace();                        }                    }                }            }        });    }    private void setSaveDataClickListener() {        findViewById(R.id.btnSaveData).setOnClickListener(new OnClickListener() {            @Override            public void onClick(View v) {                FileOutputStream out = null;                try {                    out=openFileOutput("file.dat", MODE_PRIVATE);                    String text=met.getText().toString();                    byte[] data=text.getBytes("utf-8");//FileOutputStream时data要转换为字节数组                    out.write(data);                    out.flush();                } catch (FileNotFoundException e) {                    e.printStackTrace();                } catch (UnsupportedEncodingException e) {                    e.printStackTrace();                } catch (IOException e) {                    e.printStackTrace();                }finally{                    if(out!=null){                        try {                            out.close();                        } catch (IOException e) {                            e.printStackTrace();                        }                    }                }            }        });    }    private void initView() {        met=(EditText) findViewById(R.id.et);    }}

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