<pre name="code" class="html"><!-- 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"/>
//判断sd卡是否存在
private boolean ExistSDCard() {
if (android.os.Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED)) {
return true;
} else
return false;
}
private void initView(){
img=(ImageView)findViewById(R.id.img);
Handler handler=new Handler(); //新建一个Handler对象
handler.post(a); } //更新UI 用到Handler和Runnable结合
Runnable a =new Runnable(){
@Overrid
private void run(){
Bitmap bitmap=BitmapFactory.decodeFile("/mnt/sdcard/a.jpg/");
img.setImageBitmap(bitmap);
}
};
<pre name="code" class="java"> private String filePath=Environment.getExternalStorageDirectory() + "/"+"a.jpg";
File file=new File(filePath);
if(file.exist()){...} //判断是否存在文件