package com.example.android_file;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.PrintStream;
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.Toast;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button = (Button) findViewById(R.id.button1);
button.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// write("测试字符串");
writeSDFile("测试字符串");
}
});
Button button2 = (Button) findViewById(R.id.button2);
button2.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// Toast.makeText(MainActivity.this, read(), 200).show();
Toast.makeText(MainActivity.this, readSDFile(), 200).show();
}
});
}
/**
* 向程序作用域文件写入内容,路径:/data/data/com.example.android_file/files
*
* @param content
*/
private void write(String content) {
try {
FileOutputStream fileOutputStream = openFileOutput("file.txt",
Activity.MODE_APPEND);
PrintStream printStream = new PrintStream(fileOutputStream);
printStream.println(content);
printStream.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
/**
* 获取程序作用域文件的内容,路径:/data/data/com.example.android_file/files
*
* @return
*/
private String read() {
StringBuffer stringBuffer = new StringBuffer();
FileInputStream fileInputStream = null;
try {
// openFileInput
fileInputStream = openFileInput("file.txt");
byte[] bytes = new byte[1024];
int len = 0;
while ((len = fileInputStream.read(bytes)) != -1) {
stringBuffer.append(new String(bytes, "utf-8"));
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
fileInputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return stringBuffer.toString();
}
/**
* 向SD文件写入内容
*
* @param content
*/
private void writeSDFile(String content) {
if (Environment.getExternalStorageState().equals(
Environment.MEDIA_MOUNTED)) {
try {
// 获取sd的路径
String path = Environment.getExternalStorageDirectory()
.getCanonicalPath() + "/file.txt";
FileOutputStream fileOutputStream = new FileOutputStream(path,
true);// true:追加方式
PrintStream printStream = new PrintStream(fileOutputStream);
printStream.println(content);
printStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
/**
* 获取SD卡文件内容
*
* @return
*/
private String readSDFile() {
StringBuffer stringBuffer = new StringBuffer();
FileInputStream fileInputStream = null;
if (Environment.getExternalStorageState().equals(
Environment.MEDIA_MOUNTED)) {
// 获取sd的路径
try {
String path = Environment.getExternalStorageDirectory()
.getCanonicalPath() + "/file.txt";
fileInputStream = new FileInputStream(path);
byte[] bytes = new byte[1024];
int len = 0;
while ((len = fileInputStream.read(bytes)) != -1) {
stringBuffer.append(new String(bytes, "utf-8"));
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
fileInputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return stringBuffer.toString();
}
}
openFileOutput和openFileInput 只能用于/data/data/包名/files 下文件的操作
