Java tutorial
/* * Copyright (C) 2016 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); you may not * use this file except in compliance with the License. You may obtain a copy of * the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations under * the License. */ package com.android.talkback.menurules; import com.google.android.marvin.talkback.TalkBackService; import android.app.AlertDialog; import android.content.Context; import android.content.DialogInterface; import android.content.DialogInterface.OnDismissListener; import android.os.Build; import android.os.Bundle; import android.support.v4.os.BuildCompat; import android.support.v4.view.accessibility.AccessibilityNodeInfoCompat; import android.support.v4.view.accessibility.AccessibilityNodeInfoCompat.RangeInfoCompat; import android.view.KeyEvent; import android.view.LayoutInflater; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.view.View.OnClickListener; import android.view.View.OnFocusChangeListener; import android.view.WindowManager; import android.view.accessibility.AccessibilityNodeInfo; import android.view.accessibility.AccessibilityNodeInfo.AccessibilityAction; import android.view.inputmethod.EditorInfo; import android.widget.Button; import android.widget.EditText; import android.widget.TextView; import android.widget.TextView.OnEditorActionListener; import com.android.talkback.R; import com.android.talkback.contextmenu.ContextMenuItem; import com.android.talkback.contextmenu.ContextMenuItemBuilder; import com.android.utils.AccessibilityNodeInfoUtils; import com.android.utils.PerformActionUtils; import java.util.LinkedList; import java.util.List; /** * Provides a LCM item to manually enter a percentage value for seek controls. * This functionality is only available on Android N and later. */ public class RuleSeekBar implements NodeMenuRule { @Override public boolean accept(TalkBackService service, AccessibilityNodeInfoCompat node) { if (!BuildCompat.isAtLeastN()) { return false; } return AccessibilityNodeInfoUtils.supportsAction(node, AccessibilityNodeInfo.AccessibilityAction.ACTION_SET_PROGRESS.getId()); } @Override public List<ContextMenuItem> getMenuItemsForNode(TalkBackService service, ContextMenuItemBuilder menuItemBuilder, AccessibilityNodeInfoCompat node) { List<ContextMenuItem> items = new LinkedList<>(); if (node != null) { final ContextMenuItem setLevel = menuItemBuilder.createMenuItem(service, Menu.NONE, R.id.seekbar_breakout_set_level, Menu.NONE, service.getString(R.string.title_seek_bar_edit)); setLevel.setOnMenuItemClickListener(new SeekBarDialogManager(service, node)); setLevel.setSkipRefocusEvents(true); items.add(setLevel); } return items; } @Override public CharSequence getUserFriendlyMenuName(Context context) { return context.getString(R.string.title_seek_bar_controls); } @Override public boolean canCollapseMenu() { return true; } private static int realToPercent(float real, float min, float max) { return (int) (100.0f * (real - min) / (max - min)); } private static float percentToReal(int percent, float min, float max) { return min + (percent / 100.0f) * (max - min); } // Separate package-private method so we can test the logic. static void setProgress(AccessibilityNodeInfoCompat node, int progress) { RangeInfoCompat rangeInfo = node.getRangeInfo(); if (rangeInfo != null && progress >= 0 && progress <= 100) { Bundle args = new Bundle(); args.putFloat(AccessibilityNodeInfo.ACTION_ARGUMENT_PROGRESS_VALUE, percentToReal(progress, rangeInfo.getMin(), rangeInfo.getMax())); PerformActionUtils.performAction(node, AccessibilityAction.ACTION_SET_PROGRESS.getId(), args); } } // Deals with opening the dialog from the menu item and controlling the dialog lifecycle. private static class SeekBarDialogManager implements MenuItem.OnMenuItemClickListener, OnDismissListener { private static final int INVALID_VALUE = -1; private final TalkBackService mService; private AccessibilityNodeInfoCompat mSeekBar; // Note: not final so we can null it out. private int mOldValue = INVALID_VALUE; private int mValue = INVALID_VALUE; private View mRootView; private AlertDialog mDialog; public SeekBarDialogManager(TalkBackService service, AccessibilityNodeInfoCompat seekBar) { mService = service; mSeekBar = AccessibilityNodeInfoCompat.obtain(seekBar); } @Override public boolean onMenuItemClick(MenuItem item) { // Verify that node is OK and get the current seek control level first. final RangeInfoCompat rangeInfo = mSeekBar.getRangeInfo(); if (rangeInfo == null) { return false; } mOldValue = realToPercent(rangeInfo.getCurrent(), rangeInfo.getMin(), rangeInfo.getMax()); mService.saveFocusedNode(); LayoutInflater inflater = LayoutInflater.from(mService); mRootView = inflater.inflate(R.layout.seekbar_level_dialog, null); final AlertDialog.Builder builder = new AlertDialog.Builder(mService).setView(mRootView) .setTitle(mService.getString(R.string.title_seek_bar_edit)) .setPositiveButton(android.R.string.ok, null).setNegativeButton(android.R.string.cancel, null) .setCancelable(true).setOnDismissListener(this); mDialog = builder.create(); if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP_MR1) { mDialog.getWindow().setType(WindowManager.LayoutParams.TYPE_ACCESSIBILITY_OVERLAY); } else { mDialog.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ERROR); } mDialog.show(); mService.getRingerModeAndScreenMonitor().registerDialog(mDialog); // We'd like to keep focus off of the text field until the user activates it. final Button okButton = mDialog.getButton(DialogInterface.BUTTON_POSITIVE); okButton.setFocusableInTouchMode(true); okButton.requestFocus(); // Fill in the text field and restore normal input focus behavior when it gets focus. final EditText percentage = (EditText) mRootView.findViewById(R.id.seek_bar_level); percentage.setText(Integer.toString(mOldValue)); percentage.setOnFocusChangeListener(new OnFocusChangeListener() { @Override public void onFocusChange(View v, boolean hasFocus) { if (hasFocus) { okButton.setFocusableInTouchMode(false); } } }); percentage.setOnEditorActionListener(new OnEditorActionListener() { @Override public boolean onEditorAction(TextView v, int actionId, KeyEvent event) { if (actionId == EditorInfo.IME_ACTION_DONE) { submitDialog(); return true; } return false; } }); // Use our own custom listener to prevent the dialog from closing if there's an error. okButton.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { submitDialog(); } }); return true; } @Override public void onDismiss(DialogInterface dialog) { if (mSeekBar == null) { return; } // This will only set the value if the user clicked "OK" because only "OK" will // change the mValue field to not be INVALID_VALUE. if (mValue != INVALID_VALUE && mValue != mOldValue) { setProgress(mSeekBar, mValue); } mService.resetFocusedNode(); mService.getRingerModeAndScreenMonitor().unregisterDialog(dialog); mSeekBar.recycle(); mSeekBar = null; } private void submitDialog() { if (mRootView == null || mDialog == null) { return; } final EditText percentage = (EditText) mRootView.findViewById(R.id.seek_bar_level); try { int percentValue = Integer.parseInt(percentage.getText().toString()); if (percentValue < 0 || percentValue > 100) { throw new IndexOutOfBoundsException(); } // Need to delay setting value until the dialog is dismissed. mValue = percentValue; mDialog.dismiss(); } catch (NumberFormatException | IndexOutOfBoundsException ex) { // Set the error text popup. CharSequence instructions = mService.getString(R.string.value_seek_bar_dialog_instructions); percentage.setError(instructions); } } } }