Android数据读取 写入操作(SD卡文件存储、SharedPreferences存储)_android 实现读取sd卡上的文件的存取: (1)界面包括一个edittext和一个textvi

// =================get SDCard information===================
    public static boolean isSdcardAvailable() {
        String status = Environment.getExternalStorageState();
        //Environment.MEDIA_MOUNTED表示SD卡正常挂载
        if (status.equals(Environment.MEDIA_MOUNTED)) {
            return true;
        }
        return false;
    }
 
    public static long getSDAllSizeKB() {
        //sd卡的位置
        File path = Environment.getExternalStorageDirectory();
        //StatFs获取的都是以block为单位的
        StatFs sf = new StatFs(path.getPath());
        // 得到单个block的大小
        long blockSize = sf.getBlockSize();
        // 获取所有数据块数
        long allBlocks = sf.getBlockCount();
        // 返回SD卡大小
        return (allBlocks * blockSize) / 1024; // KB
    }
 
    /**
     * free size for normal application
     * @return
     */
    public static long getSDAvalibleSizeKB() {
        File path = Environment.getExternalStorageDirectory();
        StatFs sf = new StatFs(path.getPath());
        long blockSize = sf.getBlockSize();
        long avaliableSize = sf.getAvailableBlocks();
        return (avaliableSize * blockSize) / 1024;// KB
    }

case R.id.button1: {
            Log.d("TEST", "sdcard?"+FileUtil.isSdcardAvailable());
            Log.d("TEST", "全部容量"+(float)FileUtil.getSDAllSizeKB()/1024/1024);
            Log.d("TEST", "可用容量"+(float)FileUtil.getSDAvalibleSizeKB()/1024/1024);
            Toast.makeText(this, "status", Toast.LENGTH_SHORT).show();
            break;
        }

/**
     * @param director 文件夹名称
     * @return
     */
    public static boolean isFileExist(String director) {
        File file = new File(Environment.getExternalStorageDirectory()
                + File.separator + director);
        return file.exists();
    }
 
    /**
     * create multiple director
     * @param path
     * @return
     */
    public static boolean createFile(String director) {
        if (isFileExist(director)) {
            return true;
        } else {
            File file = new File(Environment.getExternalStorageDirectory()
                    + File.separator + director);
            if (!file.mkdirs()) {
                return false;
            }
            return true;
        }
    }

//在界面组件或服务组件中调用，构造应用默认的设置文件，默认文件名字为_preferences.xml
        //userInfo = PreferenceManager.getDefaultSharedPreferences(this);  
        //或获取指定名字的SharedPreferences对象  参数分别为存储的文件名和存储模式。
        userInfo = getSharedPreferences("preferences", Activity.MODE_PRIVATE); 
        
        //读取数据，如果无法找到则会使用默认值
        String username = userInfo.getString("name", "未定义姓名");  
        String msg = userInfo.getString("msg", "未定义信息");
        //显示文本
        textView.setText(username+","+msg);

case R.id.button7: {
            //获得SharedPreferences的编辑器
            SharedPreferences.Editor editor = userInfo.edit();
            //将信息存入相应的键值中
            editor.putString("name", editText.getText().toString()).commit();
            Toast.makeText(this, "SetName", Toast.LENGTH_SHORT).show();
            break;
        } 
        case R.id.button8: {
            //获得SharedPreferences的编辑器
            SharedPreferences.Editor editor = userInfo.edit();
            //将信息存入相应的键值中ss
            editor.putString("msg", editText.getText().toString()).commit();
            Toast.makeText(this, "SetMessage", Toast.LENGTH_SHORT).show();
            break;
        } 
        case R.id.button9: {             //获得SharedPreferences文件
            userInfo = getSharedPreferences("preferences", Activity.MODE_PRIVATE);
            String username = userInfo.getString("name", "未定义姓名");  
            String msg = userInfo.getString("msg", "未定义信息");
            textView.setText(username+","+msg);
            Toast.makeText(this, "ShowMsg", Toast.LENGTH_SHORT).show();
            break;
        } 
        case R.id.button10: {             //输出XML文件
            textView.setText(print());
            Toast.makeText(this, "ShowXML", Toast.LENGTH_SHORT).show();
            break;
        }

package com.example.administrator.myapplication;
 
        import java.io.File;
        import java.io.FileInputStream;
        import java.io.FileNotFoundException;
        import java.io.FileOutputStream;
        import java.io.IOException;
        import java.io.InputStream;
        import java.io.OutputStream;
        import android.os.Environment;
        import android.os.StatFs;
        import android.util.Log;
 
        import org.apache.http.util.EncodingUtils;
 
public class FileUtil {
    private static int bufferd = 1024;
    private FileUtil() {
    }
 
    /*
     * <!-- 在SDCard中创建与删除文件权限 --> <uses-permission
     * android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/> <!--
     * 往SDCard写入数据权限 --> <uses-permission
     * android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
     */
    // =================get SDCard information===================
    public static boolean isSdcardAvailable() {
        String status = Environment.getExternalStorageState();
        if (status.equals(Environment.MEDIA_MOUNTED)) {
            return true;
        }
        return false;
    }
 
    public static long getSDAllSizeKB() {
        // get path of sdcard
        File path = Environment.getExternalStorageDirectory();
        //StatFs获取的都是以block为单位的   http://blog.csdn.net/pang3510726681/article/details/6969557
        StatFs sf = new StatFs(path.getPath());
        // get single block size(Byte)
        long blockSize = sf.getBlockSize();
        // 获取所有数据块数
        long allBlocks = sf.getBlockCount();
        // 返回SD卡大小
        return (allBlocks * blockSize) / 1024; // KB
    }
 
    /**
     * free size for normal application
     *
     * @return
     */
    public static long getSDAvalibleSizeKB() {
        File path = Environment.getExternalStorageDirectory();
        StatFs sf = new StatFs(path.getPath());
        long blockSize = sf.getBlockSize();
        long avaliableSize = sf.getAvailableBlocks();
        return (avaliableSize * blockSize) / 1024;// KB
    }
 
    // =====================File Operation==========================
    /**
     * @param director 文件夹名称
     * @return
     */
    public static boolean isFileExist(String director) {
        File file = new File(Environment.getExternalStorageDirectory()
                + File.separator + director);
        return file.exists();
    }
 
 
    public static boolean createFile(String director) {
        if (isFileExist(director)) {
            return true;
        } else {
            File file = new File(Environment.getExternalStorageDirectory()
                    + File.separator + director);
            if (!file.mkdirs()) {
                return false;
            }
            return true;
        }
    }
 
    public static File writeToSDCardFile(String directory, String fileName,
                                         String content, boolean isAppend) {
        return writeToSDCardFile(directory, fileName, content, "", isAppend);
    }
 
 
    public static File writeToSDCardFile(String directory, String fileName,
                                         String content, String encoding, boolean isAppend) {
        // mobile SD card path +path
        File file = null;
        OutputStream os = null;
        try {
            if (!createFile(directory)) {
                return file;
            }
            file = new File(Environment.getExternalStorageDirectory()
                    + File.separator + directory + File.separator + fileName);
            os = new FileOutputStream(file, isAppend);
            if (encoding.equals("")) {
                os.write(content.getBytes());
            } else {
                os.write(content.getBytes(encoding));
            }
            os.flush();
        } catch (IOException e) {
            Log.e("FileUtil", "writeToSDCardFile:" + e.getMessage());
        } finally {
            try {
                if (os != null) {
                    os.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return file;
    }
 
    /**
     * write data from inputstream to SDCard
     */
    public static File writeToSDCardFromInput(String directory, String fileName,
                                              InputStream input) {
        File file = null;
        OutputStream os = null;
        try {
            if (createFile(directory)) {
                return file;
            }
            file = new File(Environment.getExternalStorageDirectory()
                    + File.separator + directory + File.separator + fileName);
            os = new FileOutputStream(file);
            byte[] data = new byte[bufferd];
            int length = -1;
            while ((length = input.read(data)) != -1) {
                os.write(data, 0, length);
            }
            // clear cache
            os.flush();
        } catch (Exception e) {
            Log.e("FileUtil", "" + e.getMessage());
            e.printStackTrace();
        } finally {
            try {
                os.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return file;
    }
 
    public static String ReadFromSDCardFile(String directory,String fileName){
        String res="";
        File file = null;
        file = new File(Environment.getExternalStorageDirectory()
                + File.separator + directory + File.separator + fileName);
        try {
            FileInputStream fis = new FileInputStream(file);
            int length = fis.available();
            byte [] buffer = new byte[length];
            fis.read(buffer);
            res = EncodingUtils.getString(buffer,"UTF-8");
            fis.close();
            return res;
        }catch (FileNotFoundException  e) {
            // TODO Auto-generated catch block
            Log.d("TEST", "FileNotFound");
            e.printStackTrace();
        }catch (Exception  e) {
            Log.d("TEST", "Can Not Open File");
            e.printStackTrace();
        }
        return null;
    }
}

package com.example.administrator.myapplication;
import android.app.Activity;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
 
import org.apache.http.util.EncodingUtils;
 
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
 
public class MainActivity extends Activity implements View.OnClickListener {
    /**
     * 存储后的文件路径：/data/data/<package name>/shares_prefs + 文件名.xml
     */
    public static final String PATH = "/data/data/com.example.administrator/shared_prefs/preferences.xml";
    private SharedPreferences userInfo;
    private Button button1;
    private Button button2;
    private Button button3;
    private Button button4;
    private Button button5;
    private Button button6;
    private Button button7;
    private Button button8;
    private Button button9;
    private Button button10;
    private TextView textView;
    private EditText editText;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        // 获得界面的控件
        textView = (TextView) findViewById(R.id.textView1);
        editText = (EditText) findViewById(R.id.editText1);
        button1 = (Button) findViewById(R.id.button1);
        button1.setOnClickListener(this);
        button2 = (Button) findViewById(R.id.button2);
        button2.setOnClickListener(this);
        button3 = (Button) findViewById(R.id.button3);
        button3.setOnClickListener(this);
        button4 = (Button) findViewById(R.id.button4);
        button4.setOnClickListener(this);
        button5 = (Button) findViewById(R.id.button5);
        button5.setOnClickListener(this);
        button6 = (Button) findViewById(R.id.button6);
        button6.setOnClickListener(this);
        button7 = (Button) findViewById(R.id.button7);
        button7.setOnClickListener(this);
        button8 = (Button) findViewById(R.id.button8);
        button8.setOnClickListener(this);
        button9 = (Button) findViewById(R.id.button9);
        button9.setOnClickListener(this);
        button10 = (Button) findViewById(R.id.button10);
        button10.setOnClickListener(this);
        //在界面组件或服务组件中调用，构造应用默认的设置文件，默认文件名字为_preferences.xml
        //userInfo = PreferenceManager.getDefaultSharedPreferences(this);
        //或获取指定名字的SharedPreferences对象  参数分别为存储的文件名和存储模式。
        userInfo = getSharedPreferences("preferences.xml", Activity.MODE_PRIVATE);
        //读取数据，如果无法找到则会使用默认值
        String username = userInfo.getString("name", "未定义姓名");
        String msg = userInfo.getString("msg", "未定义信息");
        //显示文本
        textView.setText(username + "," + msg);
    }
 
    public void onClick(View v) {
        // TODO Auto-generated method stub
        switch (v.getId()) {
            case R.id.button1: {
                Log.d("TEST", "sdcard?" + FileUtil.isSdcardAvailable());
                Log.d("TEST", "全部容量" + (float) FileUtil.getSDAllSizeKB() / 1024 / 1024);
                Log.d("TEST", "可用容量" + (float) FileUtil.getSDAvalibleSizeKB() / 1024 / 1024);
                Toast.makeText(this,"全部容量" + (float) FileUtil.getSDAllSizeKB() / 1024 / 1024, Toast.LENGTH_SHORT).show();
                break;
            }
            case R.id.button2: {
                Log.d("TEST", "example文件夹存在?" + FileUtil.isFileExist("example"));
                Log.d("TEST", "创建forexample文件夹" + FileUtil.createFile("forexample"));
                Toast.makeText(this,""+ FileUtil.isFileExist("forexample"), Toast.LENGTH_SHORT).show();
                break;
            }
            case R.id.button3: {
                FileUtil.writeToSDCardFile("forexample", "test.txt",
                        editText.getText().toString(), "UTF-8", true);
                Toast.makeText(this, "WriteFile", Toast.LENGTH_SHORT).show();
                break;
            }
            case R.id.button4: {
                textView.setText(FileUtil.ReadFromSDCardFile("forexample", "test.txt"));
                Toast.makeText(this, "ReadFile", Toast.LENGTH_SHORT).show();
                break;
            }
            case R.id.button5: {
                writeFile("test2.txt", editText.getText().toString());
                Toast.makeText(this, "WritePrivateFile", Toast.LENGTH_SHORT).show();
                break;
            }
            case R.id.button6: {
                textView.setText(readFile("test2.txt"));
                Toast.makeText(this, "ReadPrivateFile", Toast.LENGTH_SHORT).show();
                break;
            }
            case R.id.button7: {
                //获得SharedPreferences的编辑器
                SharedPreferences.Editor editor = userInfo.edit();
                //将信息存入相应的键值中
                editor.putString("name", editText.getText().toString()).commit();
                Toast.makeText(this, "SetName", Toast.LENGTH_SHORT).show();
                break;
            }
            case R.id.button8: {
                //获得SharedPreferences的编辑器
                SharedPreferences.Editor editor = userInfo.edit();
                //将信息存入相应的键值中ss
                editor.putString("msg", editText.getText().toString()).commit();
                Toast.makeText(this, "SetMessage", Toast.LENGTH_SHORT).show();
                break;
            }
            case R.id.button9: {
                userInfo = getSharedPreferences("preferences.xml", Activity.MODE_PRIVATE);
                String username = userInfo.getString("name", "未定义姓名");
                String msg = userInfo.getString("msg", "未定义信息");
                textView.setText(username + "," + msg);
                Toast.makeText(this, "ShowMsg", Toast.LENGTH_SHORT).show();
                break;
            }
            case R.id.button10: {
                textView.setText(print());
                Toast.makeText(this, "ShowXML", Toast.LENGTH_SHORT).show();
                break;
            }
        }
    }
 
    public void writeFile(String fileName, String writestr) {
        try {
            FileOutputStream fout = openFileOutput(fileName, MODE_PRIVATE);
            byte[] bytes = writestr.getBytes();
            fout.write(bytes);
            fout.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
 
    //读数据
    public String readFile(String fileName) {
        String res = "";
        try {
            FileInputStream fin = openFileInput(fileName);
            int length = fin.available();
            byte[] buffer = new byte[length];
            fin.read(buffer);
            res = EncodingUtils.getString(buffer, "UTF-8");
            fin.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return res;
    }
 
    private String print() {
        StringBuffer buff = new StringBuffer();
        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    new FileInputStream(PATH)));
            String str;
            while ((str = reader.readLine()) != null) {
                buff.append(str + "/n");
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return buff.toString();
    }
}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >
 
 <EditText
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:id="@+id/editText1"
     />
 <TextView
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:id="@+id/textView1"
     />
 <Button
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:text="Status"
     android:id="@+id/button1"
     />
 <Button
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:text="IsFile"
     android:id="@+id/button2"
     />
 <Button
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:text="WriteFile"
     android:id="@+id/button3"
     />
 <Button
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:text="ReadFile"
     android:id="@+id/button4"
     />
 <Button
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:text="WritePrivateFile"
     android:id="@+id/button5"
     />
 <Button
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:text="ReadPrivateFile"
     android:id="@+id/button6"
     />
 <Button
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:text="SetName"
     android:id="@+id/button7"
     />
 <Button
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:text="SetMessage"
     android:id="@+id/button8"
     />
 <Button
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:text="ShowMessage"
     android:id="@+id/button9"
     />
 <Button
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:text="ShowXML"
     android:id="@+id/button10"
     />
</LinearLayout>