Android sd存储总结

Android项目上难免要使用sd卡存储，前段时间用过之后，现在想起来总结一下，顺便以后方便查阅。也写一个小demo。

源码地址：http://download.csdn.net/detail/qq_16064871/8548857

下面开始贴代码，代码上有注释。

一、DataManage类

package com.example.storagemanagedemo;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import android.os.Environment;
import android.util.Log;

public class DataManage {

	// 打开txt文件
	public String OpenTxtFile(String strPathFileName) {
		String strTxtData = "";
		// 获取sd卡存储路径根目录
		File pathFile = Environment.getExternalStorageDirectory();
		// 判断sd卡是否存在
		boolean sdCardExist = Environment.getExternalStorageState().equals(
				android.os.Environment.MEDIA_MOUNTED);
		if (sdCardExist) {
			String strpathFileName = pathFile.toString() + strPathFileName;
			// 判断是否存在这个路径是否存在这个文件
			File absolutPathFileName = new File(strpathFileName);
			if (!absolutPathFileName.exists()) {

			} else {
				strTxtData = ReadTxtDataSDFile(strpathFileName);
			}
		}
		return strTxtData;
	}

	// 保存txt格式文件
	public boolean SaveTxtFile(String strPath, String strFileName,
			String strSaveTxtData) {
		// 判断sd卡是否存在
		boolean sdCardExist = Environment.getExternalStorageState().equals(
				android.os.Environment.MEDIA_MOUNTED);
		if (sdCardExist) {
			// 获取sd卡存储路径根目录
			File pathFile = Environment.getExternalStorageDirectory();

			// 按照SD卡指定的路径创建文件夹
			File absolutPathFile = new File(pathFile.toString() + strPath);
			if (!absolutPathFile.exists()) {
				absolutPathFile.mkdirs();
			}

			// 在指定的文件夹中创建文件
			String strPathFileName = pathFile.toString() + strPath
					+ strFileName;
			File nameFile = new File(strPathFileName);
			if (!nameFile.exists()) {
				try {
					nameFile.createNewFile();
				} catch (IOException e) {
					e.printStackTrace();
					Log.i("Show", e.toString());
				}
			}

			// 调用函数向文件写入数据
			try {
				WiteTxtDataSDFile(strPathFileName, strSaveTxtData);
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}

		return false;
	}

	private String ReadTxtDataSDFile(String strpathFileName) {
		String strTxtData = "";
		try {
			FileInputStream fileInputStream = new FileInputStream(
					strpathFileName);
			int length = fileInputStream.available();
			byte[] buffer = new byte[length];
			fileInputStream.read(buffer);
			strTxtData = new String(buffer);
			fileInputStream.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return strTxtData;
	}

	// 向文件写入数据
	private void WiteTxtDataSDFile(String strPathFileName, String strSaveTxtData)
			throws IOException {
		File writefile = new File(strPathFileName);
		FileOutputStream fileOutputStream = new FileOutputStream(writefile);
		byte[] buffer = strSaveTxtData.getBytes();
		try {
			fileOutputStream.write(buffer);
			fileOutputStream.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

}

二、MainActivity类

package com.example.storagemanagedemo;

import java.io.File;

import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
import android.app.Activity;

public class MainActivity extends Activity {

	private DataManage mDataManage = new DataManage();
	private TextView showTextView;
	private TextView storageTextView;
	private EditText inputEditText;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);

		showTextView = (TextView) findViewById(R.id.textView3);
		storageTextView = (TextView) findViewById(R.id.textView1);
		inputEditText = (EditText) findViewById(R.id.editText1);
		File pathFile = Environment.getExternalStorageDirectory();
		String strpath = "存储位置以及文件名:" + pathFile.toString() + "/txt/result.txt";
		storageTextView.setText(strpath);
	}

	// 按键保存文件
	public void SavePraseData(View v) {
		mDataManage.SaveTxtFile("/txt", "/result.txt", inputEditText.getText()
				.toString());
	}

	// 按键打开文件
	public void OpenPraseData(View v) {
		String strShowDataString = "";
		strShowDataString = mDataManage.OpenTxtFile("/txt/result.txt");
		showTextView.setText(strShowDataString);
	}

}

三、xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <ScrollView
        android:id="@+id/scrollView_text"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical" >

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content" >

                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="输入数据:" />

                <EditText
                    android:id="@+id/editText1"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_weight="1"
                    android:ems="10" >

                    <requestFocus />
                </EditText>
            </LinearLayout>

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="60dp" >

                <TextView
                    android:id="@+id/textView2"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="打开数据:" />

                <TextView
                    android:id="@+id/textView3"
                    android:layout_width="match_parent"
                    android:layout_height="50dp"
                    android:text="TextView" />
            </LinearLayout>

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content" >

                <TextView
                    android:id="@+id/textView1"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="存储位置以及文件名:" />
            </LinearLayout>

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="50dp"
                android:layout_marginTop="5dp" >

                <Button
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginLeft="5dip"
                    android:onClick="SavePraseData"
                    android:text="写入sd卡" />

                <Button
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginLeft="5dip"
                    android:onClick="OpenPraseData"
                    android:text="打开文件" />
            </LinearLayout>
        </LinearLayout>
    </ScrollView>

</LinearLayout>

四、记得在AndroidManifest加入权限。

   <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />

就这些了，一定记得要加入权限。新手不断成长中，欢迎交流。

项目资源下载:http://download.csdn.net/detail/qq_16064871/8548857

转载请注明出处: http://blog.csdn.net/qq_16064871