Android四种存储方式 sharedpreference,file,SQlite,contentprovider

package cn.csdn.activity; import java.io.File; import java.io.FileNotFoundException; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import android.app.Activity; import android.os.Bundle; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.EditText; import android.widget.TextView; import android.widget.Toast; public class FileTestActivity extends Activity implements OnClickListener { private OutputStream os; /* 文件输出流，保存文件流 */ private InputStream is; /* 文件输入流，读取文件流 */ private byte[] b; /* 字节数组，用来读取文件内容 */ // 存储的文件名字 public final static String SHARED_MAIN_XML = "main.txt"; // 定义各种组件 Button buttonsave, buttonRead, clean, delete; EditText name, age; TextView contentTV; String content, namecontent; int agecontent; String savename = "无名"; int saveage = 0; protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); findViews(); content = read(); contentTV.setText(content); } private void findViews() {// 得到各组件 name = (EditText) findViewById(R.id.name); age = (EditText) findViewById(R.id.age); buttonsave = (Button) findViewById(R.id.button); buttonRead = (Button) findViewById(R.id.buttonRead); clean = (Button) findViewById(R.id.clean); delete = (Button) findViewById(R.id.delete); contentTV = (TextView) findViewById(R.id.content); buttonsave.setOnClickListener(this); buttonRead.setOnClickListener(this); clean.setOnClickListener(this); delete.setOnClickListener(this); } @Override public void onClick(View v) { switch (v.getId()) { case R.id.button:// 保存数据 write(); Toast.makeText( this, "保存成功",Toast.LENGTH_LONG).show(); break; case R.id.buttonRead:// 读出数据 content = read(); contentTV.setText(content); // Toast.makeText(this, "清除成功", Toast.LENGTH_LONG).show(); break; case R.id.clean:// 清除数据 clear(); content = read(); contentTV.setText(content); Toast.makeText(this, "清除成功", Toast.LENGTH_LONG).show(); break; case R.id.delete:// 删除文件 delete(); break; } } private void delete() { File file = new File("/data/data/cn.csdn.activity/files", SHARED_MAIN_XML); if (file.exists()) { file.delete(); } } private void clear() { String nameage=""; try { os = this.openFileOutput(SHARED_MAIN_XML, MODE_PRIVATE); /* 把字符串转换成字节数组，写入文件中 */ os.write(nameage.getBytes()); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } private String read() { String nameage=""; // 打开文件输入流， try { is = this.openFileInput(SHARED_MAIN_XML); /* 初始化字节数组 */ b = new byte[1024]; /* 从文件输入流中读取内容到字节数组中，返回内容长度 */ int length = is.read(b); /* 把字节数组转换成字符串 */ nameage= new String(b); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } return nameage; } private void write() { String nameage="名字:"+name.getText().toString().trim()+"年龄："+age.getText().toString(); try { os = this.openFileOutput(SHARED_MAIN_XML, MODE_PRIVATE); /* 把字符串转换成字节数组，写入文件中 */ os.write(nameage.getBytes()); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); }finally { try { /* 关闭文件输出流 */ os.close(); } catch (IOException e) { e.printStackTrace(); } } } }