1.sharedpreference，存储简单的信息，比如用户名，密码

package com.google.datastore.sharep;

public class SharePreferences extends Activity{

private EditText editUsername = null;
private EditText editPassword = null;

private Button bt = null;
SharedPreferences userInfo = null;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.sharepreferences);

editUsername = (EditText)findViewById(R.id.username);
editPassword = (EditText)findViewById(R.id.password);
bt = (Button)findViewById(R.id.bt);
// String s = Environment.getExternalStorageDirectory().toString();
initData();

bt.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
SharedPreferences.Editor editor = userInfo.edit();
editor.putString("name", editUsername.getText().toString());
editor.putString("password", editPassword.getText().toString());
editor.commit();
}
});
}

//
private void initData() {
userInfo = getSharedPreferences("user_info", Context.MODE_PRIVATE);
String username = userInfo.getString("name", "");
String password = userInfo.getString("password", "");

editUsername.setText(username);
editPassword.setText(password);
}

}

2.网络存储

package com.google.datastore.net;

import java.io.BufferedInputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import org.apache.http.util.ByteArrayBuffer;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;
import com.google.datastore.R;

//有问题，思路就是这样,2.3以后不能在主线程中访问网络
public class Net extends Activity{
private TextView tvNet;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.netget);

tvNet = (TextView)findViewById(R.id.textNet);
new Thread(download).start();
}
//
Runnable download = new Runnable() {
@Override
public void run() {
String msg = "";
try {
URL url = new URL("http://linux.chinaitlab.com/command/723482.html");
HttpURLConnection conn = (HttpURLConnection)url.openConnection();
conn.setReadTimeout(6 * 1000);
conn.setConnectTimeout(5 * 1000);

InputStream is = conn.getInputStream();
Log.d("lixp", "is ========" + is);
BufferedInputStream bis = new BufferedInputStream(is);
ByteArrayBuffer baf = new ByteArrayBuffer(100);

int current = 0;
while((current = bis.read()) != -1) {
baf.append((byte)current);
}

msg = new String(baf.toByteArray(), "UTF-8");
Log.d("lixp", "msg ========" + msg);
}
catch(Exception e) {
msg = e.getMessage();
Log.e("lixp", "e ===" + e);
}
// tvNet.setText(msg);
}
};
}

3.文件存储

package com.google.datastore.filestore;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import com.google.datastore.R;

public class FileActivity extends Activity{
private EditText name;
private EditText age;
private FileService fileService;
private Button saveButton;
private Button readButton;
private Button saveToSd;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.file);