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/*
* Copyright (C) 2010 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.gallery3d.photoeditor;
import android.content.Context;
import android.os.Handler;
import android.os.Message;
import android.util.AttributeSet;
import android.view.View;
import android.widget.RelativeLayout;
import com.android.gallery3d.R;
/**
* Action bar that contains buttons such as undo, redo, save, etc. and listens to stack changes for
* enabling/disabling buttons.
*/
public class ActionBar extends RelativeLayout implements FilterStack.StackListener {
/**
* Listener of action button clicked.
*/
public interface ActionBarListener {
void onUndo();
void onRedo();
void onSave();
}
private static final int ENABLE_BUTTON = 1;
private static final float ENABLED_ALPHA = 1;
private static final float DISABLED_ALPHA = 0.47f;
private final Handler handler;
private View undo;
private View redo;
private View save;
public ActionBar(Context context, AttributeSet attrs) {
super(context, attrs);
handler = new Handler() {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case ENABLE_BUTTON:
boolean canUndo = (msg.arg1 > 0);
boolean canRedo = (msg.arg2 > 0);
enableButton(undo, canUndo);
enableButton(redo, canRedo);
enableButton(save, canUndo);
break;
}
}
};
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
super.onLayout(changed, l, t, r, b);
// Show action-bar title only when there's still room for it; otherwise, hide it.
int width = 0;
for (int i = 0; i < getChildCount(); i++) {
width += getChildAt(i).getWidth();
}
findViewById(R.id.action_bar_title).setVisibility(((width > r - l)) ? INVISIBLE: VISIBLE);
}
/**
* Initializes with a non-null ActionBarListener.
*/
public void initialize(final ActionBarListener listener) {
undo = findViewById(R.id.undo_button);
undo.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
if (isEnabled()) {
listener.onUndo();
}
}
});
redo = findViewById(R.id.redo_button);
redo.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
if (isEnabled()) {
listener.onRedo();
}
}
});
save = findViewById(R.id.save_button);
save.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
if (isEnabled()) {
listener.onSave();
}
}
});
resetButtons();
}
public void resetButtons() {
// Disable buttons immediately instead of waiting for ENABLE_BUTTON messages which may
// happen some time later after stack changes.
enableButton(undo, false);
enableButton(redo, false);
enableButton(save, false);
}
public void disableSave() {
enableButton(save, false);
}
private void enableButton(View button, boolean enabled) {
button.setEnabled(enabled);
button.setAlpha(enabled ? ENABLED_ALPHA : DISABLED_ALPHA);
}
@Override
public void onStackChanged(boolean canUndo, boolean canRedo) {
// Listens to stack changes that may come from the worker thread; send messages to enable
// buttons only in the UI thread.
handler.sendMessage(handler.obtainMessage(ENABLE_BUTTON, canUndo ? 1 : 0, canRedo ? 1 : 0));
}
}
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