Java tutorial
/* * This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ package cn.tycoon.lighttrans.fileManager; import android.annotation.TargetApi; import android.app.Activity; import android.content.ClipData; import android.content.Intent; import android.net.Uri; import android.os.Build; import android.os.Bundle; import android.support.v4.app.FragmentManager; import android.support.v7.app.AppCompatActivity; import java.util.ArrayList; import java.util.List; import cn.tycoon.lighttrans.R; /** * An abstract base activity that handles all the fluff you don't care about. * <p/> * Usage: To start a child activity you could either use an intent starting the * activity directly, or you could use an implicit intent with GET_CONTENT, if * it * is also defined in your manifest. It is defined to be handled here in case * you * want the user to be able to use other file pickers on the system. * <p/> * That means using an intent with action GET_CONTENT * If you want to be able to select multiple items, include EXTRA_ALLOW_MULTIPLE * (default false). * <p/> * Two non-standard extra arguments are supported as well: EXTRA_ONLY_DIRS * (defaults to false) * allows only directories to be selected. * And EXTRA_START_PATH (default null), which should specify the starting path. * <p/> * The result of the user's action is returned in onActivityResult intent, * access it using getUri. * In case of multiple choices, these can be accessed with getClipData * containing Uri objects. * If running earlier than JellyBean you can access them with * getStringArrayListExtra(EXTRA_PATHS) * * @param <T> */ public abstract class AbstractFilePickerActivity<T> extends AppCompatActivity implements AbstractFilePickerFragment.OnFilePickedListener { public static final String EXTRA_START_PATH = "nononsense.intent" + ".START_PATH"; public static final String EXTRA_MODE = "nononsense.intent.MODE"; public static final String EXTRA_ALLOW_CREATE_DIR = "nononsense.intent" + ".ALLOW_CREATE_DIR"; // For compatibility public static final String EXTRA_ALLOW_MULTIPLE = "android.intent.extra" + ".ALLOW_MULTIPLE"; public static final String EXTRA_PATHS = "nononsense.intent.PATHS"; public static final int MODE_FILE = AbstractFilePickerFragment.MODE_FILE; public static final int MODE_FILE_AND_DIR = AbstractFilePickerFragment.MODE_FILE_AND_DIR; public static final int MODE_DIR = AbstractFilePickerFragment.MODE_DIR; protected static final String TAG = "filepicker_fragment"; protected String startPath = null; protected int mode = AbstractFilePickerFragment.MODE_FILE; protected boolean allowCreateDir = false; protected boolean allowMultiple = false; @Override @SuppressWarnings("unchecked") protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_filepicker); Intent intent = getIntent(); if (intent != null) { startPath = intent.getStringExtra(EXTRA_START_PATH); mode = intent.getIntExtra(EXTRA_MODE, mode); allowCreateDir = intent.getBooleanExtra(EXTRA_ALLOW_CREATE_DIR, allowCreateDir); allowMultiple = intent.getBooleanExtra(EXTRA_ALLOW_MULTIPLE, allowMultiple); } FragmentManager fm = getSupportFragmentManager(); AbstractFilePickerFragment<T> fragment = (AbstractFilePickerFragment<T>) fm.findFragmentByTag(TAG); if (fragment == null) { fragment = getFragment(startPath, mode, allowMultiple, allowCreateDir); } if (fragment != null) { fm.beginTransaction().replace(R.id.fragment, fragment, TAG).commit(); } // Default to cancelled setResult(Activity.RESULT_CANCELED); } protected abstract AbstractFilePickerFragment<T> getFragment(final String startPath, final int mode, final boolean allowMultiple, final boolean allowCreateDir); @Override public void onSaveInstanceState(Bundle b) { super.onSaveInstanceState(b); } @Override public void onFilePicked(final Uri file) { Intent i = new Intent(); i.setData(file); setResult(Activity.RESULT_OK, i); finish(); } @TargetApi(Build.VERSION_CODES.JELLY_BEAN) @Override public void onFilesPicked(final List<Uri> files) { Intent i = new Intent(); i.putExtra(EXTRA_ALLOW_MULTIPLE, true); if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) { ClipData clip = null; for (Uri file : files) { if (clip == null) { clip = new ClipData("Paths", new String[] {}, new ClipData.Item(file)); } else { clip.addItem(new ClipData.Item(file)); } } i.setClipData(clip); } else { ArrayList<String> paths = new ArrayList<>(); for (Uri file : files) { paths.add(file.toString()); } i.putStringArrayListExtra(EXTRA_PATHS, paths); } setResult(Activity.RESULT_OK, i); finish(); } @Override public void onCancelled() { setResult(Activity.RESULT_CANCELED); finish(); } @Override public void onBackPressed() { super.onBackPressed(); } }