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