Android SD卡读取简单操作

package com.example.sdcardtest;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.RandomAccessFile;

import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends Activity {

final String FILE_NAME = "/baidu/hello.txt";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

Button read = (Button) findViewById(R.id.read);
Button write = (Button) findViewById(R.id.write);

final EditText edit1 = (EditText) findViewById(R.id.editText1);
final EditText edit2 = (EditText) findViewById(R.id.editText2);

//为write事件绑定监听器
write.setOnClickListener(new OnClickListener() {

public void onClick(View v) {
write(edit1.getText().toString());
edit1.setText("");

}
});

//为read事件绑定监听器
read.setOnClickListener(new OnClickListener() {

public void onClick(View v) {
edit2.setText(read());
}
});

}

public String read(){
if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
File sdCardDir = Environment.getExternalStorageDirectory();
try {
FileInputStream fis = new FileInputStream(sdCardDir.getCanonicalPath() + FILE_NAME);
BufferedReader br = new BufferedReader(new InputStreamReader(fis));
StringBuilder sb = new StringBuilder("");

String line = null;
while( (line = br.readLine()) != null ){
sb.append(line);
}
br.close();
return sb.toString();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}

}
return null;
}

public void write(String content){
if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
RandomAccessFile raf = null;
try {
//获取sd卡的目录
File sdCardDir = Environment.getExternalStorageDirectory();
File targetFile = new File(sdCardDir.getCanonicalFile() + FILE_NAME);

raf = new RandomAccessFile(targetFile, "rw");
raf.seek(targetFile.length());
raf.write(content.getBytes());

} catch (IOException e) {
e.printStackTrace();
}

try {
raf.close();
} catch (IOException e) {
e.printStackTrace();
}

}
}

}
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布局文件
简单的两个按钮，没什么好说的