Android第五个功能：文件存储到SDCard上面

核心代码四部分：

1、Layout

2、String值

3、MainActivity

4、给项目添加使用授权

<?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" >    <TextView        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:text="@string/filename"         />        <EditText         android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:id="@+id/filename"        />            <TextView        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:text="@string/filecontent"         />        <EditText         android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:minLines="3"        android:id="@+id/filecontent"        />        <Button         android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="@string/button"        android:id="@+id/button"        /></LinearLayout>

package com.dcj.service;import java.io.ByteArrayOutputStream;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import android.content.Context;import android.os.Environment;public class FileService {private Context context;public FileService(Context applicationContext) {context = applicationContext;}public void saveToSDCard(String filename, String content) throws Exception {File file = new File(Environment.getExternalStorageDirectory(), filename);FileOutputStream outStream = new FileOutputStream(file);outStream.write(content.getBytes());outStream.close();}/** * 保存文件 * @param filename 文件名称 * @param content 文件内容 * @throws Exception  */public void save(String filename, String content) throws Exception {// IO j2se//私有操作模式：创建出来的文件只能被本应用访问，其它应用无法访问该文件，另外采用私有操作创建的文件，写入文件会覆盖原文件内容FileOutputStream outStream = context.openFileOutput(filename, context.MODE_PRIVATE);outStream.write(content.getBytes());outStream.close();}/** * 读取文件内容 * @param filename 文件名称 * @return 文件内容 * @throws Exception */public String read(String filename) throws Exception  {FileInputStream inStream = context.openFileInput(filename);ByteArrayOutputStream outStream = new ByteArrayOutputStream();byte[] buffer = new byte[1024];int len = 0;while ((len = inStream.read(buffer)) != -1) {outStream.write(buffer, 0, len);}byte[] data = outStream.toByteArray();return new String(data);}}

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="com.dcj"    android:versionCode="1"    android:versionName="1.0" >    <uses-sdk android:minSdkVersion="8" />    <application        android:icon="@drawable/ic_launcher"        android:label="@string/app_name" >     <uses-library android:name="android.test.runner" />        <activity            android:name=".MainActivity"            android:label="@string/app_name" >            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>    </application>     <instrumentation        android:name="android.test.InstrumentationTestRunner"        android:targetPackage="com.dcj"         android:label="Test for my App"/>          <!-- 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"/></manifest>

<?xml version="1.0" encoding="utf-8"?><resources>    <string name="hello">Hello World, MainActivity!</string>    <string name="app_name">存储到程序内部</string><string name="filename">文件名称</string><string name="filecontent">文件内容</string><string name="button">保存</string><string name="success">保存完成</string><string name="fail">保存失败</string><string name="sdcarderror">SDCard不存在或者写保护</string></resources>

package com.dcj;import com.dcj.service.FileService;import android.app.Activity;import android.os.Bundle;import android.os.Environment;import android.view.View;import android.widget.Button;import android.widget.EditText;import android.widget.Toast;import android.widget.SimpleAdapter.ViewBinder;public class MainActivity extends Activity {    /** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        Button button = (Button)this.findViewById(R.id.button);        button.setOnClickListener(new ButtonClickListener());    }        private final class ButtonClickListener implements View.OnClickListener {    public void onClick(View v) {    EditText filenameText = (EditText) findViewById(R.id.filename);    EditText contentText = (EditText) findViewById(R.id.filecontent);    String filename = filenameText.getText().toString();    String content = contentText.getText().toString();        FileService service = new FileService(getApplicationContext());    try {//service.save(filename, content);    //换成保存到SDCard上面    //判断SDCard是否存在，并且可以读写    if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {    service.saveToSDCard(filename, content);    Toast.makeText(getApplicationContext(), R.string.success, 1).show();    }else{    Toast.makeText(getApplicationContext(), R.string.sdcarderror, 1).show();    }} catch (Exception e) {Toast.makeText(getApplicationContext(), R.string.fail, 1).show();e.printStackTrace();}}    }}

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