/*
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* Copyright (C) 2006 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 android.widget;
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import android.content.Context;
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import android.util.AttributeSet;
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import android.view.LayoutInflater;
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import android.view.MotionEvent;
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import android.view.PointerIcon;
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import android.widget.RemoteViews.RemoteView;
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/**
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* A user interface element the user can tap or click to perform an action.
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*
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* <p>To display a button in an activity, add a button to the activity's layout XML file:</p>
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*
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* <pre>
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* <Button
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* android:id="@+id/button_id"
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* android:layout_height="wrap_content"
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* android:layout_width="wrap_content"
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* android:text="@string/self_destruct" /></pre>
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*
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* <p>To specify an action when the button is pressed, set a click
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* listener on the button object in the corresponding activity code:</p>
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*
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* <pre>
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* public class MyActivity extends Activity {
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* protected void onCreate(Bundle savedInstanceState) {
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* super.onCreate(savedInstanceState);
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*
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* setContentView(R.layout.content_layout_id);
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*
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* final Button button = findViewById(R.id.button_id);
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* button.setOnClickListener(new View.OnClickListener() {
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* public void onClick(View v) {
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* // Code here executes on main thread after user presses button
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* }
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* });
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* }
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* }</pre>
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*
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* <p>The above snippet creates an instance of {@link android.view.View.OnClickListener} and wires
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* the listener to the button using
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* {@link #setOnClickListener setOnClickListener(View.OnClickListener)}.
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* As a result, the system executes the code you write in {@code onClick(View)} after the
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* user presses the button.</p>
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*
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* <p class="note">The system executes the code in {@code onClick} on the
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* <a href="{@docRoot}guide/components/processes-and-threads.html#Threads">main thread</a>.
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* This means your onClick code must execute quickly to avoid delaying your app's response
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* to further user actions. See
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* <a href="{@docRoot}training/articles/perf-anr.html">Keeping Your App Responsive</a>
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* for more details.</p>
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*
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* <p>Every button is styled using the system's default button background, which is often
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* different from one version of the platform to another. If you are not satisfied with the
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* default button style, you can customize it. For more details and code samples, see the
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* <a href="{@docRoot}guide/topics/ui/controls/button.html#Style">Styling Your Button</a>
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* guide.</p>
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*
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* <p>For all XML style attributes available on Button see
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* {@link android.R.styleable#Button Button Attributes},
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* {@link android.R.styleable#TextView TextView Attributes},
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* {@link android.R.styleable#View View Attributes}. See the
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* <a href="{@docRoot}guide/topics/ui/themes.html#ApplyingStyles">Styles and Themes</a>
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* guide to learn how to implement and organize overrides to style-related attributes.</p>
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*/
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@RemoteView
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public class Button extends TextView {
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/**
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* Simple constructor to use when creating a button from code.
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*
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* @param context The Context the Button is running in, through which it can
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* access the current theme, resources, etc.
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*
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* @see #Button(Context, AttributeSet)
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*/
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public Button(Context context) {
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this(context, null);
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}
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/**
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* {@link LayoutInflater} calls this constructor when inflating a Button from XML.
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* The attributes defined by the current theme's
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* {@link android.R.attr#buttonStyle android:buttonStyle}
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* override base view attributes.
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*
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* You typically do not call this constructor to create your own button instance in code.
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* However, you must override this constructor when
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* <a href="{@docRoot}training/custom-views/index.html">creating custom views</a>.
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*
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* @param context The Context the view is running in, through which it can
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* access the current theme, resources, etc.
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* @param attrs The attributes of the XML Button tag being used to inflate the view.
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*
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* @see #Button(Context, AttributeSet, int)
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* @see android.view.View#View(Context, AttributeSet)
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*/
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public Button(Context context, AttributeSet attrs) {
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this(context, attrs, com.android.internal.R.attr.buttonStyle);
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}
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/**
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* This constructor allows a Button subclass to use its own class-specific base style from a
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* theme attribute when inflating. The attributes defined by the current theme's
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* {@code defStyleAttr} override base view attributes.
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*
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* <p>For Button's base view attributes see
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* {@link android.R.styleable#Button Button Attributes},
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* {@link android.R.styleable#TextView TextView Attributes},
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* {@link android.R.styleable#View View Attributes}.
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*
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* @param context The Context the Button is running in, through which it can
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* access the current theme, resources, etc.
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* @param attrs The attributes of the XML Button tag that is inflating the view.
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* @param defStyleAttr The resource identifier of an attribute in the current theme
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* whose value is the the resource id of a style. The specified style’s
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* attribute values serve as default values for the button. Set this parameter
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* to 0 to avoid use of default values.
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* @see #Button(Context, AttributeSet, int, int)
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* @see android.view.View#View(Context, AttributeSet, int)
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*/
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public Button(Context context, AttributeSet attrs, int defStyleAttr) {
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this(context, attrs, defStyleAttr, 0);
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}
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/**
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* This constructor allows a Button subclass to use its own class-specific base style from
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* either a theme attribute or style resource when inflating. To see how the final value of a
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* particular attribute is resolved based on your inputs to this constructor, see
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* {@link android.view.View#View(Context, AttributeSet, int, int)}.
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*
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* @param context The Context the Button is running in, through which it can
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* access the current theme, resources, etc.
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* @param attrs The attributes of the XML Button tag that is inflating the view.
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* @param defStyleAttr The resource identifier of an attribute in the current theme
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* whose value is the the resource id of a style. The specified style’s
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* attribute values serve as default values for the button. Set this parameter
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* to 0 to avoid use of default values.
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* @param defStyleRes The identifier of a style resource that
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* supplies default values for the button, used only if
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* defStyleAttr is 0 or cannot be found in the theme.
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* Set this parameter to 0 to avoid use of default values.
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*
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* @see #Button(Context, AttributeSet, int)
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* @see android.view.View#View(Context, AttributeSet, int, int)
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*/
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public Button(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
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super(context, attrs, defStyleAttr, defStyleRes);
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}
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@Override
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public CharSequence getAccessibilityClassName() {
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return Button.class.getName();
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}
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@Override
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public PointerIcon onResolvePointerIcon(MotionEvent event, int pointerIndex) {
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if (getPointerIcon() == null && isClickable() && isEnabled()) {
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return PointerIcon.getSystemIcon(getContext(), PointerIcon.TYPE_HAND);
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}
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return super.onResolvePointerIcon(event, pointerIndex);
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}
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}
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