文件读写
Android SDCard操作(文件读写,容量计算) ：http://zhuyonghui116.blog.hexun.com/56778119_d.html
Android中读写文件： http://blog.csdn.net/cocodehouse/article/details/5974288
增加权限：<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
String sDStateString = android.os.Environment.getExternalStorageState();
// 拥有可读可写权限
if (sDStateString.equals(android.os.Environment.MEDIA_MOUNTED)) {
... ...
}
然后用FileInputStream和FileOutputStream进行读写。
package com.file.rw;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import android.app.Activity;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.EditText;import android.widget.TextView;public class ReadWriteFilesActivity extends Activity { /** Called when the activity is first created. */private Button button1,button2;private EditText editText1,editText2;private TextView textview; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); button1=(Button)findViewById(R.id.button1); button2=(Button)findViewById(R.id.button2); editText1 = (EditText)findViewById(R.id.editText1); editText2 = (EditText)findViewById(R.id.editText2); textview =(TextView)findViewById(R.id.textview); //load file from sd card button1.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubtextview.setText("Load............");String sdStatus = android.os.Environment.getExternalStorageState();if(sdStatus.equalsIgnoreCase(android.os.Environment.MEDIA_MOUNTED)){textview.setText(editText1.getText());File rootDir = android.os.Environment.getExternalStorageDirectory();File readFile = new File(rootDir.getAbsolutePath()+File.separator+editText1.getText());if(!readFile.exists()){textview.setText(editText1.getText()+"不存在.");}else{try {FileInputStream in = new FileInputStream(readFile);byte[] buffer = new byte[in.available()];in.read(buffer);in.close();editText2.setText(new String(buffer));} catch (Exception e) {// TODO: handle exceptione.printStackTrace();}}}//end of android.os.Environment.MEDIA_MOUNTED}}); button2.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubif(editText1.getText()==null||editText1.getText().toString().trim().length()==0){textview.setText("第一个输入框没有输入文件名.");return;}if(editText2.getText()==null||editText2.getText().toString().trim().length()==0){textview.setText("第而个输入框没有输入文件内容.");return;}String sdStatus = android.os.Environment.getExternalStorageState();if(android.os.Environment.MEDIA_MOUNTED.equalsIgnoreCase(sdStatus)){File root = android.os.Environment.getExternalStorageDirectory();File newFile = new File(root.getAbsolutePath()+File.separator+editText1.getText());try {if(!newFile.exists()){newFile.createNewFile();}FileOutputStream out = new FileOutputStream(newFile);out.write(editText2.getText().toString().getBytes());out.close();textview.setText("写文件成功.");} catch (Exception e) {// TODO: handle exception}}}}); }}
