Android 开发笔记___SD卡基本操作

 1 package com.example.alimjan.hello_world;
 2 
 3 /**
 4  * Created by alimjan on 7/5/2017.
 5  */
 6 
 7         import android.annotation.TargetApi;
 8         import android.content.Context;
 9         import android.content.Intent;
10         import android.os.Build;
11         import android.os.Build.VERSION;
12         import android.os.Bundle;
13         import android.os.Environment;
14         import android.support.v7.app.AppCompatActivity;
15         import android.widget.TextView;
16 
17 public class class__4_3_1 extends AppCompatActivity {
18 
19     private TextView tv_file_basic;
20 
21     @Override
22     protected void onCreate(Bundle savedInstanceState) {
23         super.onCreate(savedInstanceState);
24         setContentView(R.layout.code_4_3_1);
25         tv_file_basic = (TextView) findViewById(R.id.tv_file_basic);
26         getEnvironmentInfo();
27     }
28 
29     @TargetApi(Build.VERSION_CODES.KITKAT)
30     private void getEnvironmentInfo() {
31         String desc = "系统环境（含SD卡）的信息如下：";
32         desc = String.format("%s
　根目录路径：%s", desc,
33                 Environment.getRootDirectory().getAbsolutePath());
34         desc = String.format("%s
　数据目录路径：%s", desc,
35                 Environment.getDataDirectory().getAbsolutePath());
36         desc = String.format("%s
　下载缓存目录路径：%s", desc,
37                 Environment.getDownloadCacheDirectory().getAbsolutePath());
38         desc = String.format("%s
　外部存储(即SD卡)目录路径：%s", desc,
39                 Environment.getExternalStorageDirectory().getAbsolutePath());
40         desc = String.format("%s
　外部存储(即SD卡)状态：%s", desc,
41                 Environment.getExternalStorageState());
42         desc = String.format("%s
　SD卡的相机目录路径：%s", desc,
43                 Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM));
44         //DIRECTORY_DOCUMENTS是Android4.4.2（SDK19）及以上版本才有的常量
45         //如果不做SDK版本判断，那么在低版本Android(例如4.2.2)上运行会报错
46         //java.lang.NoSuchFieldError: android.os.Environment.DIRECTORY_DOCUMENTS
47         if (VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
48             desc = String.format("%s
　SD卡的文档目录路径：%s", desc,
49                     Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOCUMENTS));
50         }
51         desc = String.format("%s
　SD卡的下载目录路径：%s", desc,
52                 Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS));
53         desc = String.format("%s
　SD卡的图片目录路径：%s", desc,
54                 Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES));
55         desc = String.format("%s
　SD卡的视频目录路径：%s", desc,
56                 Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MOVIES));
57         desc = String.format("%s
　SD卡的音乐目录路径：%s", desc,
58                 Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MUSIC));
59         tv_file_basic.setText(desc);
60     }
61 
62     public static void startHome(Context mcontext){
63         Intent intent = new Intent(mcontext,class__4_3_1.class);
64         mcontext.startActivity(intent);
65     }
66 
67 }

 1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     android:layout_width="match_parent"
 3     android:layout_height="match_parent"
 4     android:focusable="true"
 5     android:focusableInTouchMode="true"
 6     android:orientation="vertical"
 7     android:padding="10dp" >
 8 
 9     <TextView
10         android:id="@+id/tv_file_basic"
11         android:layout_width="match_parent"
12         android:layout_height="wrap_content"
13         android:textColor="@color/black"
14         android:textSize="17sp" />
15 
16 </LinearLayout>