Android 读写文件整理

很简单的整理，最近实在心力憔悴，贴上整理代码：
package xiaolei.sun.readwrite;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.os.Environment;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.util.Xml;import android.view.View;import android.view.accessibility.AccessibilityEvent;import android.widget.ImageView;import android.widget.TextView;import android.widget.Toast;import java.io.BufferedInputStream;import java.io.BufferedReader;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.InputStreamReader;import java.io.PrintStream;import java.io.RandomAccessFile;public class MainActivity extends AppCompatActivity {    private TextView textview;    private ImageView imageView;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        textview = (TextView) findViewById(R.id.textview);        imageView =                (ImageView) findViewById(R.id.iv_imageview);    }    public void btn_imagefuc(View view) {        String path = null;        try {            path = Environment.getExternalStorageDirectory().getCanonicalPath() + "/a.png";           //字节流            FileInputStream fs = new FileInputStream(path);           //字节缓冲流            BufferedInputStream bufferedInputStream = new BufferedInputStream(fs); //bufferedInputStream作为一个流的缓冲池，提高流的写入性能呢            //在加载前可计算图像大小，进行图片压缩            // 将流转换为bitmap            Bitmap bitmap = BitmapFactory.decodeStream(bufferedInputStream);            imageView.setImageBitmap(bitmap);            bufferedInputStream.close();            fs.close();            bitmap = null;        } catch (IOException e) {            e.printStackTrace();        }        Toast.makeText(MainActivity.this, "123", Toast.LENGTH_SHORT).show();    }    public void getSDfuc(View view) {        boolean equals = Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED);        File externalStorageDirectory = Environment.getExternalStorageDirectory();        Toast.makeText(MainActivity.this, externalStorageDirectory + "", Toast.LENGTH_SHORT).show();    }    public void SDwritefuc(View view) {        writetoSDcard("SD card example !!!");        Toast.makeText(MainActivity.this, "SD write !!!", Toast.LENGTH_SHORT).show();    }    /**     * 将数据写入SD卡     *     * @param content     */    public void writetoSDcard(String content) {        if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED))// 判断SD卡是否进行挂载        {            File externalStorageDirectory = Environment.getExternalStorageDirectory();// 获取SD卡路径            // 创建一个文件，并使用RandomAccessFile进行文件写入            try {                File file = new File(externalStorageDirectory.getCanonicalPath() + "/text.txt");                RandomAccessFile randomAccessFile = new RandomAccessFile(file, "rw");                randomAccessFile.seek(file.length());                randomAccessFile.write(content.getBytes());//数据写入                randomAccessFile.close();            } catch (IOException e) {                e.printStackTrace();            }        }    }    /**     * 读取SD卡中的内容     *     * @return     */    public String ReadFromSDcard() {        File externalStorageDirectory = Environment.getExternalStorageDirectory(); //获取SD卡路径        try {            //获取读取流            FileInputStream fileInputStream = new FileInputStream(externalStorageDirectory.getCanonicalPath() + "/text.txt");            //将读取流转换为bufferReader            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(fileInputStream));            StringBuilder stringBuilder = new StringBuilder("");            String line = null;            //使用bufferReader将stringBuilder拼接起来            while ((line = bufferedReader.readLine()) != null) {                stringBuilder.append(line);            }            bufferedReader.close();            return stringBuilder.toString();        } catch (IOException e) {            e.printStackTrace();        }        return null;    }    public void SDreadfuc(View view) {        textview.setText(ReadFromSDcard());        ;        Toast.makeText(MainActivity.this, "SD read !!!", Toast.LENGTH_SHORT).show();    }    public void getdirfuc(View view) {        File dir = getDir("dirtext.txt", MODE_APPEND);//  在应用程序下获取路径        File filesDir = getFilesDir();        String[] strings = fileList();        deleteFile("text.txt");        Toast.makeText(MainActivity.this, strings[0], Toast.LENGTH_SHORT).show();    }    public void writefuc(View view) {        write("this is a text file!!!");        Toast.makeText(MainActivity.this, "write", Toast.LENGTH_SHORT).show();    }    public void readfuc(View view) {        textview.setText(read());        Toast.makeText(MainActivity.this, "read", Toast.LENGTH_SHORT).show();    }    public void write(String content) {        try {            FileOutputStream fileOutputStream = openFileOutput("text.txt", MODE_APPEND);            PrintStream printStream = new PrintStream(fileOutputStream);            printStream.println(content);            printStream.close();        } catch (FileNotFoundException e) {            e.printStackTrace();        }    }    public String read() {        try {            FileInputStream fileInputStream = openFileInput("text.txt");            byte[] bytes = new byte[1024];            int hasread = 0;            StringBuilder stringBuilder = new StringBuilder("");            while ((hasread = fileInputStream.read(bytes)) > 0) {                stringBuilder.append(new String(bytes, 0, hasread));            }            fileInputStream.close();            return stringBuilder.toString();        } catch (FileNotFoundException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        }        return null;    }}
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