MainActivity如下:
package cc.cv;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
/**
* Demo描述:
* 文件存储详细示例
*
* 可利用Context的openFileOutput()方法将数据存储到文件中.
* 默认的存储路径为/data/data/<packageName>/files/
* 可利用Context的openFileInput()方法将数据从文件中读出
*
* 在Android中常用的存储方式:
* SharedPreferences,数据库,SD卡,文件存储.
* 对于最后一种方式平时用的不多,现在此写个例子
* 整理和复习一下.
*
* 注意事项:
* 文件存储是不需要权限的与在SD卡上进行文件存储是不一样的
*/
public class MainActivity extends Activity {
private Button mSaveButton;
private Button mGetButton;
private Context mContext;
private String mFileName;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
init();
}
private void init(){
mContext=this;
mFileName="testData";
mSaveButton=(Button) findViewById(R.id.saveButton);
mSaveButton.setOnClickListener(new ClickListenerImpl());
mGetButton=(Button) findViewById(R.id.getButton);
mGetButton.setOnClickListener(new ClickListenerImpl());
}
private class ClickListenerImpl implements OnClickListener{
@Override
public void onClick(View view) {
switch (view.getId()) {
case R.id.saveButton:
saveDataToFile(mContext,mFileName);
break;
case R.id.getButton:
getDataFromFile(mContext,mFileName);
break;
default:
break;
}
}
}
/**
* 向File中保存数据
*/
private void saveDataToFile(Context context,String fileName){
String data="Hello,All";
FileOutputStream fileOutputStream=null;
OutputStreamWriter outputStreamWriter=null;
BufferedWriter bufferedWriter=null;
try {
fileOutputStream=context.openFileOutput(fileName, Context.MODE_PRIVATE);
outputStreamWriter=new OutputStreamWriter(fileOutputStream);
bufferedWriter=new BufferedWriter(outputStreamWriter);
bufferedWriter.write(data);
} catch (Exception e) {
e.printStackTrace();
}finally{
try {
if (bufferedWriter!=null) {
bufferedWriter.close();
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
/**
* 从File中读取数据
*/
private void getDataFromFile(Context context,String fileName){
FileInputStream fileInputStream=null;
InputStreamReader inputStreamReader=null;
BufferedReader bufferedReader=null;
StringBuilder stringBuilder=null;
String line=null;
try {
stringBuilder=new StringBuilder();
fileInputStream=context.openFileInput(fileName);
inputStreamReader=new InputStreamReader(fileInputStream);
bufferedReader=new BufferedReader(inputStreamReader);
while((line=bufferedReader.readLine())!=null){
stringBuilder.append(line);
}
System.out.println("--->"+stringBuilder.toString());
} catch (Exception e) {
e.printStackTrace();
}finally{
try {
if (bufferedReader!=null) {
bufferedReader.close();
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
main.xml如下:
<RelativeLayout 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"
>
<Button
android:id="@+id/saveButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="向File中保存数据"
android:layout_centerHorizontal="true"
android:layout_marginTop="100dp" />
<Button
android:id="@+id/getButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="从File中获取数据"
android:layout_centerHorizontal="true"
android:layout_marginTop="260dp" />
</RelativeLayout>
