为了让用户删除他们不再需要的文件，我有一个列表视图，它显示位于 SD 卡上的目录中的文件列表。我现在需要找到一种方法来检索每个文件的路径，以某种方式将其链接到列表视图中的相应项目并让用户删除该文件。我做了一个对话框，当一个项目被长按时会弹出；我现在需要在此人按下“确定”按钮后删除 SD 卡上的文件。这些文件都是在不同的活动中创建的，所以我假设必须通过意图传递一些东西。
ReadFilesFromDirectory.java
public class ReadFilesFromPath extends Activity {
/** Called when the activity is first created. */
List<String> myList;
File file;
ListView listview;
ArrayAdapter<String> adapter;
String value;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.recordinglist);
Intent intent = getIntent();
value = intent.getStringExtra("path"); //if it's a string you stored.
listview = (ListView) findViewById(R.id.recordlist);
myList = new ArrayList<String>();
onitemclick();
File directory = Environment.getExternalStorageDirectory();
file = new File( directory + "/" + "Recordings" );
File list[] = file.listFiles();
for( int i=0; i< list.length; i++)
{
myList.add( list[i].getName() );
}
adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, android.R.id.text1, myList);
listview.setAdapter(adapter); //Set all the file in the list.
longclick();
}
public void longclick() {
listview.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
public boolean onItemLongClick(AdapterView<?> arg0, View v,
int pos, long arg3) {
AlertDialog.Builder adb=new AlertDialog.Builder(ReadFilesFromPath.this); //alert for each time an item is pressed
adb.setTitle("Delete?");
adb.setMessage("Are you sure you want to delete this recording?");
final int positionToRemove = pos;
adb.setNegativeButton("Cancel", null);
adb.setPositiveButton("Ok", new AlertDialog.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
listview.animate().setDuration(500).alpha(0) //animates a smooth deletion animation
.withEndAction(new Runnable() {
@Override
public void run() {
//DELETE THE FILE HERE
Toast.makeText(getApplicationContext(), "Deleted", Toast.LENGTH_SHORT).show();
myList.remove(positionToRemove); //removes the selected item
adapter.notifyDataSetChanged(); //tells the adapter to delete it
listview.setAlpha(1);
}
});
}});
adb.show();
return true;
}
});
}
public void onitemclick() {
listview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, final View view,
int position, long id) {
}
});
}
@Override
public void onBackPressed() {
// TODO Auto-generated method stub
super.onBackPressed();
overridePendingTransition(R.anim.push_right_in, R.anim.push_right_out);
}
}
我将文件的数据保存在这样的不同活动中（类中有更多方法，但它们不影响文件的保存）：
public class MainActivity extends Activity {
MediaRecorder recorder;
File audiofile = null, file, directory;
private static final String TAG = "SoundRecordingActivity";
Button startButton, stopButton, openfiles, recordingbtn, delete, aboutbtn, exitbtn;
TextView welcometext;
SimpleDateFormat df;
String formattedDate, name, value, pathToExternalStorage;
String[] toastMessages;
File appDirectory, filetodelete;
int randomMsgIndex, number;
CheckBox mp4;
ContentValues values;
Uri base, newUri;
Boolean recordingstarted;
List<String> myList;
ListView listview;
ArrayAdapter<String> adapter;
private MenuDrawer mDrawer;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//setContentView(R.layout.activity_main);
mDrawer = MenuDrawer.attach(this, Position.BOTTOM);
mDrawer.setContentView(R.layout.activity_main);
mDrawer.setMenuView(R.layout.leftmenu);
Calendar c = Calendar.getInstance();
df = new SimpleDateFormat("hh:mm:ss");
formattedDate = df.format(c.getTime());
name = "Recording";
listview = (ListView)findViewById(R.id.recordlist);
exitbtn = (Button)findViewById(R.id.exitbtn);
openfiles = (Button)findViewById(R.id.openfilesbtn);
aboutbtn = (Button)findViewById(R.id.aboutbtn);
startButton = (Button) findViewById(R.id.start);
stopButton = (Button) findViewById(R.id.stop);
pathToExternalStorage = Environment.getExternalStorageDirectory().toString();
appDirectory = new File(pathToExternalStorage + "/" + "Recordify");
Typeface myTypeface = Typeface.createFromAsset(getAssets(), "fonts/robothin.ttf");
welcometext = (TextView)findViewById(R.id.welcomeandtimetext);
welcometext.setTypeface(myTypeface);
onclicks();
startandstop();
}
protected void addRecordingToMediaLibrary() {
values = new ContentValues(4);
values.put(MediaStore.Audio.Media.TITLE, name); //"audio" + audiofile.getName()
values.put(MediaStore.Audio.Media.MIME_TYPE, "video/mp4"); //sets the type to be a mp4 video file, despite being audio
values.put(MediaStore.Audio.Media.DATA, audiofile.getAbsolutePath());
ContentResolver contentResolver = getContentResolver();
base = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
newUri = contentResolver.insert(base, values);
sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, newUri));
welcometext.setText("Saved as " + audiofile); //teling users what name of file is called
}