The file containing the source code shown below is located in the corresponding directory in <sdk>/samples/android-<version>/...
/*
* Copyright (C) 2008-2009 The Android开源工程
*
* 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.example.android.softkeyboard;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;
import java.util.ArrayList;
import java.util.List;
public class CandidateView extends View {
private static final int OUT_OF_BOUNDS = -1;
private SoftKeyboard mService;
private List<String> mSuggestions;
private int mSelectedIndex;
private int mTouchX = OUT_OF_BOUNDS;
private Drawable mSelectionHighlight;
private boolean mTypedWordValid;
private Rect mBgPadding;
private static final int MAX_SUGGESTIONS = 32;
private static final int SCROLL_PIXELS = 20;
private int[] mWordWidth = new int[MAX_SUGGESTIONS];
private int[] mWordX = new int[MAX_SUGGESTIONS];
private static final int X_GAP = 10;
private static final List<String> EMPTY_LIST = new ArrayList<String>();
private int mColorNormal;
private int mColorRecommended;
private int mColorOther;
private int mVerticalPadding;
private Paint mPaint;
private boolean mScrolled;
private int mTargetScrollX;
private int mTotalWidth;
private GestureDetector mGestureDetector;
/**
* Construct a CandidateView for showing suggested words for completion.
* @param context
* @param attrs
*/
public CandidateView(Context context) {
super(context);
mSelectionHighlight = context.getResources().getDrawable(
android.R.drawable.list_selector_background);
mSelectionHighlight.setState(new int[] {
android.R.attr.state_enabled,
android.R.attr.state_focused,
android.R.attr.state_window_focused,
android.R.attr.state_pressed
});
Resources r = context.getResources();
setBackgroundColor(r.getColor(R.color.candidate_background));
mColorNormal = r.getColor(R.color.candidate_normal);
mColorRecommended = r.getColor(R.color.candidate_recommended);
mColorOther = r.getColor(R.color.candidate_other);
mVerticalPadding = r.getDimensionPixelSize(R.dimen.candidate_vertical_padding);
mPaint = new Paint();
mPaint.setColor(mColorNormal);
mPaint.setAntiAlias(true);
mPaint.setTextSize(r.getDimensionPixelSize(R.dimen.candidate_font_height));
mPaint.setStrokeWidth(0);
mGestureDetector = new GestureDetector(new GestureDetector.SimpleOnGestureListener() {
@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2,
float distanceX, float distanceY) {
mScrolled = true;
int sx = getScrollX();
sx += distanceX;
if (sx < 0) {
sx = 0;
}
if (sx + getWidth() > mTotalWidth) {
sx -= distanceX;
}
mTargetScrollX = sx;
scrollTo(sx, getScrollY());
invalidate();
return true;
}
});
setHorizontalFadingEdgeEnabled(true);
setWillNotDraw(false);
setHorizontalScrollBarEnabled(false);
setVerticalScrollBarEnabled(false);
}
/**
* A connection back to the service to communicate with the text field
* @param listener
*/
public void setService(SoftKeyboard listener) {
mService = listener;
}
@Override
public int computeHorizontalScrollRange() {
return mTotalWidth;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int measuredWidth = resolveSize(50, widthMeasureSpec);
// Get the desired height of the icon menu view (last row of items does
// not have a divider below)
Rect padding = new Rect();
mSelectionHighlight.getPadding(padding);
final int desiredHeight = ((int)mPaint.getTextSize()) + mVerticalPadding
+ padding.top + padding.bottom;
// Maximum possible width and desired height
setMeasuredDimension(measuredWidth,
resolveSize(desiredHeight, heightMeasureSpec));
}
/**
* If the canvas is null, then only touch calculations are performed to pick the target
* candidate.
*/
@Override
protected void onDraw(Canvas canvas) {
if (canvas != null) {
super.onDraw(canvas);
}
mTotalWidth = 0;
if (mSuggestions == null) return;
if (mBgPadding == null) {
mBgPadding = new Rect(0, 0, 0, 0);
if (getBackground() != null) {
getBackground().getPadding(mBgPadding);
}
}
int x = 0;
final int count = mSuggestions.size();
final int height = getHeight();
final Rect bgPadding = mBgPadding;
final Paint paint = mPaint;
final int touchX = mTouchX;
final int scrollX = getScrollX();
final boolean scrolled = mScrolled;
final boolean typedWordValid = mTypedWordValid;
final int y = (int) (((height - mPaint.getTextSize()) / 2) - mPaint.ascent());
for (int i = 0; i < count; i++) {
String suggestion = mSuggestions.get(i);
float textWidth = paint.measureText(suggestion);
final int wordWidth = (int) textWidth + X_GAP * 2;
mWordX[i] = x;
mWordWidth[i] = wordWidth;
paint.setColor(mColorNormal);
if (touchX + scrollX >= x && touchX + scrollX < x + wordWidth && !scrolled) {
if (canvas != null) {
canvas.translate(x, 0);
mSelectionHighlight.setBounds(0, bgPadding.top, wordWidth, height);
mSelectionHighlight.draw(canvas);
canvas.translate(-x, 0);
}
mSelectedIndex = i;
}
if (canvas != null) {
if ((i == 1 && !typedWordValid) || (i == 0 && typedWordValid)) {
paint.setFakeBoldText(true);
paint.setColor(mColorRecommended);
} else if (i != 0) {
paint.setColor(mColorOther);
}
canvas.drawText(suggestion, x + X_GAP, y, paint);
paint.setColor(mColorOther);
canvas.drawLine(x + wordWidth + 0.5f, bgPadding.top,
x + wordWidth + 0.5f, height + 1, paint);
paint.setFakeBoldText(false);
}
x += wordWidth;
}
mTotalWidth = x;
if (mTargetScrollX != getScrollX()) {
scrollToTarget();
}
}
private void scrollToTarget() {
int sx = getScrollX();
if (mTargetScrollX > sx) {
sx += SCROLL_PIXELS;
if (sx >= mTargetScrollX) {
sx = mTargetScrollX;
requestLayout();
}
} else {
sx -= SCROLL_PIXELS;
if (sx <= mTargetScrollX) {
sx = mTargetScrollX;
requestLayout();
}
}
scrollTo(sx, getScrollY());
invalidate();
}
public void setSuggestions(List<String> suggestions, boolean completions,
boolean typedWordValid) {
clear();
if (suggestions != null) {
mSuggestions = new ArrayList<String>(suggestions);
}
mTypedWordValid = typedWordValid;
scrollTo(0, 0);
mTargetScrollX = 0;
// Compute the total width
onDraw(null);
invalidate();
requestLayout();
}
public void clear() {
mSuggestions = EMPTY_LIST;
mTouchX = OUT_OF_BOUNDS;
mSelectedIndex = -1;
invalidate();
}
@Override
public boolean onTouchEvent(MotionEvent me) {
if (mGestureDetector.onTouchEvent(me)) {
return true;
}
int action = me.getAction();
int x = (int) me.getX();
int y = (int) me.getY();
mTouchX = x;
switch (action) {
case MotionEvent.ACTION_DOWN:
mScrolled = false;
invalidate();
break;
case MotionEvent.ACTION_MOVE:
if (y <= 0) {
// Fling up!?
if (mSelectedIndex >= 0) {
mService.pickSuggestionManually(mSelectedIndex);
mSelectedIndex = -1;
}
}
invalidate();
break;
case MotionEvent.ACTION_UP:
if (!mScrolled) {
if (mSelectedIndex >= 0) {
mService.pickSuggestionManually(mSelectedIndex);
}
}
mSelectedIndex = -1;
removeHighlight();
requestLayout();
break;
}
return true;
}
/**
* For flick through from keyboard, call this method with the x coordinate of the flick
* gesture.
* @param x
*/
public void takeSuggestionAt(float x) {
mTouchX = (int) x;
// To detect candidate
onDraw(null);
if (mSelectedIndex >= 0) {
mService.pickSuggestionManually(mSelectedIndex);
}
invalidate();
}
private void removeHighlight() {
mTouchX = OUT_OF_BOUNDS;
invalidate();
}
}