/*
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* Copyright (C) 2014 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.android.camera.widget;
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import android.content.Context;
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import android.graphics.Canvas;
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import android.util.AttributeSet;
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import android.view.View;
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import android.widget.TextView;
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/**
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* This class defines a generic cling that provides on-screen instructions. A convenient
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* method is provided here to automatically adjust the position of the cling to
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* always be consistent with the reference view. The use of the convenient method
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* is optional.
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*/
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public class Cling extends TextView {
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private View mReferenceView = null;
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private final int[] mLocation = new int[2];
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private final OnLayoutChangeListener mLayoutChangeListener =
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new OnLayoutChangeListener() {
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@Override
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public void onLayoutChange(View v, int left, int top, int right, int bottom,
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int oldLeft, int oldTop, int oldRight, int oldBottom) {
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mDelayDrawingUntilNextLayout = false;
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// Reference view has changed layout.
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adjustPosition();
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}
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};
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private boolean mDelayDrawingUntilNextLayout = false;
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public Cling(Context context, AttributeSet attrs) {
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super(context, attrs);
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}
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public Cling(Context context) {
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super(context);
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}
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/**
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* Layout on top of a reference view.
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*/
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public void setReferenceView(View v) {
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if (v == null) {
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if (mReferenceView != null) {
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// Clear up existing listeners
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mReferenceView.removeOnLayoutChangeListener(mLayoutChangeListener);
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mReferenceView = null;
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}
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return;
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}
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mReferenceView = v;
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mReferenceView.addOnLayoutChangeListener(mLayoutChangeListener);
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if (mReferenceView.getVisibility() == GONE) {
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mDelayDrawingUntilNextLayout = true;
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} else {
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adjustPosition();
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}
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}
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/**
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* Adjust the translation of the cling to stay on top of the reference view.
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*/
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public void adjustPosition() {
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if (mReferenceView == null) {
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return;
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}
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mReferenceView.getLocationInWindow(mLocation);
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int refCenterX = mLocation[0] + mReferenceView.getWidth() / 2;
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int refTopY = mLocation[1];
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// Align center with the reference view and move on top
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int left = refCenterX - getWidth() / 2;
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int top = refTopY - getHeight();
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getLocationInWindow(mLocation);
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int currentLeft = mLocation[0] - (int) getTranslationX();
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int currentTop = mLocation[1] - (int) getTranslationY();
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setTranslationX(left - currentLeft);
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setTranslationY(top - currentTop);
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}
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@Override
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public void draw(Canvas canvas) {
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if (mDelayDrawingUntilNextLayout) {
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return;
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}
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super.draw(canvas);
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}
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}
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