content: /*
   * 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>
   * &lt;Button
   *     android:id="@+id/button_id"
   *     android:layout_height="wrap_content"
   *     android:layout_width="wrap_content"
   *     android:text="@string/self_destruct" /&gt;</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);
      }
  }
  