/*
* Copyright (C) 2006 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 android.text.method;
import android.util.Log;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.text.*;
import android.widget.TextView;
import android.view.View;
public class
ScrollingMovementMethod
implements MovementMethod
{
/**
* Scrolls the text to the left if possible.
*/
protected boolean left(TextView widget, Spannable buffer) {
Layout layout = widget.getLayout();
int scrolly = widget.getScrollY();
int scr = widget.getScrollX();
int em = Math.round(layout.getPaint().getFontSpacing());
int padding = widget.getTotalPaddingTop() +
widget.getTotalPaddingBottom();
int top = layout.getLineForVertical(scrolly);
int bottom = layout.getLineForVertical(scrolly + widget.getHeight() -
padding);
int left = Integer.MAX_VALUE;
for (int i = top; i <= bottom; i++) {
left = (int) Math.min(left, layout.getLineLeft(i));
}
if (scr > left) {
int s = Math.max(scr - em, left);
widget.scrollTo(s, widget.getScrollY());
return true;
}
return false;
}
/**
* Scrolls the text to the right if possible.
*/
protected boolean right(TextView widget, Spannable buffer) {
Layout layout = widget.getLayout();
int scrolly = widget.getScrollY();
int scr = widget.getScrollX();
int em = Math.round(layout.getPaint().getFontSpacing());
int padding = widget.getTotalPaddingTop() +
widget.getTotalPaddingBottom();
int top = layout.getLineForVertical(scrolly);
int bottom = layout.getLineForVertical(scrolly + widget.getHeight() -
padding);
int right = 0;
for (int i = top; i <= bottom; i++) {
right = (int) Math.max(right, layout.getLineRight(i));
}
padding = widget.getTotalPaddingLeft() + widget.getTotalPaddingRight();
if (scr < right - (widget.getWidth() - padding)) {
int s = Math.min(scr + em, right - (widget.getWidth() - padding));
widget.scrollTo(s, widget.getScrollY());
return true;
}
return false;
}
/**
* Scrolls the text up if possible.
*/
protected boolean up(TextView widget, Spannable buffer) {
Layout layout = widget.getLayout();
int areatop = widget.getScrollY();
int line = layout.getLineForVertical(areatop);
int linetop = layout.getLineTop(line);
// If the top line is partially visible, bring it all the way
// into view; otherwise, bring the previous line into view.
if (areatop == linetop)
line--;
if (line >= 0) {
Touch.scrollTo(widget, layout,
widget.getScrollX(), layout.getLineTop(line));
return true;
}
return false;
}
/**
* Scrolls the text down if possible.
*/
protected boolean down(TextView widget, Spannable buffer) {
Layout layout = widget.getLayout();
int padding = widget.getTotalPaddingTop() +
widget.getTotalPaddingBottom();
int areabot = widget.getScrollY() + widget.getHeight() - padding;
int line = layout.getLineForVertical(areabot);
if (layout.getLineTop(line+1) < areabot + 1) {
// Less than a pixel of this line is out of view,
// so we must have tried to make it entirely in view
// and now want the next line to be in view instead.
line++;
}
if (line <= layout.getLineCount() - 1) {
widget.scrollTo(widget.getScrollX(), layout.getLineTop(line+1) -
(widget.getHeight() - padding));
Touch.scrollTo(widget, layout,
widget.getScrollX(), widget.getScrollY());
return true;
}
return false;
}
public boolean onKeyDown(TextView widget, Spannable buffer, int keyCode, KeyEvent event) {
return executeDown(widget, buffer, keyCode);
}
private boolean executeDown(TextView widget, Spannable buffer, int keyCode) {
boolean handled = false;
switch (keyCode) {
case KeyEvent.KEYCODE_DPAD_LEFT:
handled |= left(widget, buffer);
break;
case KeyEvent.KEYCODE_DPAD_RIGHT:
handled |= right(widget, buffer);
break;
case KeyEvent.KEYCODE_DPAD_UP:
handled |= up(widget, buffer);
break;
case KeyEvent.KEYCODE_DPAD_DOWN:
handled |= down(widget, buffer);
break;
}
return handled;
}
public boolean onKeyUp(TextView widget, Spannable buffer, int keyCode, KeyEvent event) {
return false;
}
public boolean onKeyOther(TextView view, Spannable text, KeyEvent event) {
int code = event.getKeyCode();
if (code != KeyEvent.KEYCODE_UNKNOWN
&& event.getAction() == KeyEvent.ACTION_MULTIPLE) {
int repeat = event.getRepeatCount();
boolean first = true;
boolean handled = false;
while ((--repeat) > 0) {
if (first && executeDown(view, text, code)) {
handled = true;
MetaKeyKeyListener.adjustMetaAfterKeypress(text);
MetaKeyKeyListener.resetLockedMeta(text);
}
first = false;
}
return handled;
}
return false;
}
public boolean onTrackballEvent(TextView widget, Spannable text,
MotionEvent event) {
return false;
}
public boolean onTouchEvent(TextView widget, Spannable buffer,
MotionEvent event) {
return Touch.onTouchEvent(widget, buffer, event);
}
public void initialize(TextView widget, Spannable text) { }
public boolean canSelectArbitrarily() {
return false;
}
public void onTakeFocus(TextView widget, Spannable text, int dir) {
Layout layout = widget.getLayout();
if (layout != null && (dir & View.FOCUS_FORWARD) != 0) {
widget.scrollTo(widget.getScrollX(),
layout.getLineTop(0));
}
if (layout != null && (dir & View.FOCUS_BACKWARD) != 0) {
int padding = widget.getTotalPaddingTop() +
widget.getTotalPaddingBottom();
int line = layout.getLineCount() - 1;
widget.scrollTo(widget.getScrollX(),
layout.getLineTop(line+1) -
(widget.getHeight() - padding));
}
}
public static MovementMethod getInstance() {
if (sInstance == null)
sInstance = new ScrollingMovementMethod();
return sInstance;
}
private static ScrollingMovementMethod sInstance;
}