<!-- 在SDCard中創(chuàng)建與刪除文件權(quán)限 --><uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/><!-- 往SDCard寫入數(shù)據(jù)權(quán)限 --><uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="fill_parent"android:layout_height="fill_parent"android:orientation="vertical" ><TextViewandroid:layout_width="fill_parent"android:layout_height="wrap_content"android:text="@string/hello" /><EditTextandroid:id="@+id/et1"android:layout_width="fill_parent"android:layout_height="wrap_content" /><Buttonandroid:id="@+id/bt1"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="使用SDcard寫操作" /><EditTextandroid:id="@+id/et2"android:layout_width="fill_parent"android:layout_height="wrap_content" /><Buttonandroid:id="@+id/bt2"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="使用SDcard讀操作" /></LinearLayout> 

import android.os.Bundle;import android.os.Environment;import android.support.v7.app.AppCompatActivity;import android.view.Menu;import android.view.MenuItem;import android.widget.TextView;import org.apache.http.util.EncodingUtils;import java.io.BufferedReader;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.util.ArrayList;import java.util.List;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import android.app.Activity;import android.content.Context;import android.os.Bundle;import android.os.Environment;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.EditText;import android.widget.Toast;public class MainActivity extends AppCompatActivity {private Button bt1, bt2;private EditText et1, et2;private static final String FILENAME = "temp_file.txt";@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);bt1 = (Button) this.findViewById(R.id.bt1);bt2 = (Button) this.findViewById(R.id.bt2);et1 = (EditText) this.findViewById(R.id.et1);et2 = (EditText) this.findViewById(R.id.et2);bt1.setOnClickListener(new MySetOnClickListener());bt2.setOnClickListener(new MySetOnClickListener());}private class MySetOnClickListener implements OnClickListener {@Overridepublic void onClick(View v) {File file = new File(Environment.getExternalStorageDirectory(),FILENAME);switch (v.getId()) {case R.id.bt1:// 使用SDcard寫操作if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {try {FileOutputStream fos = new FileOutputStream(file);fos.write(et1.getText().toString().getBytes());fos.close();Toast.makeText(MainActivity.this, "寫入文件成功",Toast.LENGTH_LONG).show();} catch (Exception e) {Toast.makeText(MainActivity.this, "寫入文件失敗",Toast.LENGTH_SHORT).show();}} else {// 此時(shí)SDcard不存在或者不能進(jìn)行讀寫操作的Toast.makeText(MainActivity.this,"此時(shí)SDcard不存在或者不能進(jìn)行讀寫操作", Toast.LENGTH_SHORT).show();}break;case R.id.bt2:// 使用SDcard讀操作if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {try {FileInputStream inputStream = new FileInputStream(file);byte[] b = new byte[inputStream.available()];inputStream.read(b);et2.setText(new String(b));Toast.makeText(MainActivity.this, "讀取文件成功",Toast.LENGTH_LONG).show();} catch (Exception e) {Toast.makeText(MainActivity.this, "讀取失敗",Toast.LENGTH_SHORT).show();}} else {// 此時(shí)SDcard不存在或者不能進(jìn)行讀寫操作的Toast.makeText(MainActivity.this,"此時(shí)SDcard不存在或者不能進(jìn)行讀寫操作", Toast.LENGTH_SHORT).show();}break;}}}@Overridepublic boolean onCreateOptionsMenu(Menu menu) {// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.menu_main, menu);return true;}@Overridepublic boolean onOptionsItemSelected(MenuItem item) {// Handle action bar item clicks here. The action bar will// automatically handle clicks on the Home/Up button, so long// as you specify a parent activity in AndroidManifest.xml.int id = item.getItemId();//noinspection SimplifiableIfStatementif (id == R.id.action_settings) {return true;}return super.onOptionsItemSelected(item);}}